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In ancient times, only the
Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
and
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
, a few
star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
s, and the most easily visible
planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...
s had names. Over the last few hundred years, the number of identified
astronomical object An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...
s has risen from hundreds to over a billion, and more are discovered every year.
Astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
s need to be able to assign systematic designations to unambiguously identify all of these objects, and at the same time give names to the most interesting objects, and where relevant, features of those objects. The
International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
(IAU) is the recognized authority in
astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...
for assigning designations to celestial bodies such as stars, planets, and
minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
s, including any surface features on them. In response to the need for unambiguous names for astronomical objects, it has created a number of systematic naming systems for objects of various sorts.


Stars

There are no more than a few thousand stars that appear sufficiently bright in Earth's sky to be visible to the
naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...
. This represents the number of stars available to be named by ancient cultures. The upper boundary to what is physiologically possible to be seen with the unaided eye is an apparent
magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...
of 6, or about ten thousand stars. With the advent of the increased light-gathering abilities of the telescope, many more stars became visible, far too many to all be given names. The earliest naming system which is still popular is the
Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...
using the name of
constellations A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellations were likely defin ...
to identify the stars within them. The IAU is the only internationally recognized authority for assigning astronomical designations to
celestial object An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe. In astronomy, the terms ''object'' and ''body'' are of ...
s and surface features on them. The purpose of this is to ensure that names assigned are unambiguous. There have been many historical
star catalogue A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the year ...
s, and new star catalogues are set up on a regular basis as new sky surveys are performed. All designations of objects in recent star catalogues start with an "initialism", which is kept globally unique by the IAU. Different star catalogues then have different naming conventions for what goes after the initialism, but modern catalogs tend to follow a set of generic rules for the data formats used. The IAU does not recognize the commercial practice of selling fictitious star names by commercial star-naming companies.


Proper names

There are about 300 to 350 stars with traditional or historical proper names. They tend to be the
brightest stars This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a ''V''-band filter in the UBV photometric system. Stars ...
in the sky and are often the most prominent ones of the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
. Examples are
Betelgeuse Betelgeuse is a red supergiant star in the constellation of Orion (constellation), Orion. It is usually the List of brightest stars, tenth-brightest star in the night sky and, after Rigel, the second brightest in its constellation. It i ...
,
Rigel Rigel is a blue supergiant star in the constellation of Orion. It has the Bayer designation β Orionis, which is Latinized to Beta Orionis and abbreviated Beta Ori or β Ori. Rigel is the brightest and most massive componentand ...
and
Vega Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, and ...
. Most such names are derived from the
Arabic language Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...
''(see List of Arabic star names § History of Arabic star names)''. Stars may have multiple proper names, as many different cultures named them independently.
Polaris Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris (Latinisation of names, Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an ...
, for example, has also been known by the names ''Alruccabah'', ''Angel Stern, Cynosura'', the ''Lodestar'', ''Mismar'', ''Navigatoria'', ''Phoenice'', the ''Pole Star'', the ''Star of Arcady'', ''Tramontana'' and ''Yilduz'' at various times and places by different cultures in human history. In 2016, the
IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
organized a
Working Group on Star Names The International Astronomical Union (IAU) established a Working Group on Star Names (WGSN) in May 2016 to catalog and standardize proper names for stars for the international astronomical community. It operates under Division C – Education ...
(WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN (on 30 June and 20 July 2016) together with names of stars adopted by the IAU Executive Committee Working Group on Public Naming of Planets and Planetary Satellites during the 2015 NameExoWorlds campaign and recognized by the WGSN. Further batches of names were approved on 21 August 2016, 12 September 2016 and 5 October 2016. These were listed in a table included in the WGSN's second bulletin issued in October 2016. The next additions were done on 1 February, 30 June, 5 September and 19 November 2017, and on 6 June 2018. All are included on the current List of IAU-approved Star Names. The star nearest to Earth is typically referred to simply as "the Sun" or its equivalent in the language being used (for instance, if two astronomers were speaking French, they would call it ''le Soleil''). However, it is usually called by its
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
name, Sol, in science fiction.


Named after people

There are about two dozen stars such as
Barnard's Star Barnard's Star is a small red dwarf star in the constellation of Ophiuchus. At a distance of from Earth, it is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and is the c ...
and
Kapteyn's Star Kapteyn's Star is a class M1 red subdwarf about 12.83 light-years from Earth in the southern constellation Pictor; it is the closest halo star to the Solar System. With an apparent magnitude of nearly 9, it is visible through binocul ...
that have historic names and which were named in honor after
astronomer An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
s. As a result of the NameExoWorlds campaign in December 2015 the IAU approved the names Cervantes (honoring the writer
Miguel de Cervantes Miguel de Cervantes Saavedra ( ; ; 29 September 1547 (assumed) – 22 April 1616 Old Style and New Style dates, NS) was a Spanish writer widely regarded as the greatest writer in the Spanish language and one of the world's pre-eminent novelist ...
) and Copernicus (honoring the astronomer
Nicolaus Copernicus Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...
) for the stars
Mu Arae Mu Arae is a single star with a planetary system in the constellation of Ara. Its name is a Bayer designation that is Latinized from μ Arae, and abbreviated Mu Ara or μ Ara. This star is officially named Cervantes, pronounced or , ...
and 55 Cancri A, respectively. In July 2016, the IAU WGSN approved the name ''Cor Caroli'' (
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
for 'heart of Charles') for the star Alpha Canum Venaticorum, so named in honour of
King Charles I of England Charles I (19 November 1600 – 30 January 1649) was King of England, Scotland, and Ireland from 27 March 1625 until his execution in 1649. Charles was born into the House of Stuart as the second son of King James VI of Scotland, but after h ...
by Sir
Charles Scarborough Sir Charles Scarborough or Scarburgh Member of Parliament, MP Fellow of the Royal Society, FRS Fellow of the Royal College of Physicians, FRCP (29 December 1615 – 26 February 1694) was an English physician and mathematician.Robert L. Martensen ...
, his physician. In 2019, IAU held the
NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) were various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, notably exoplanets. The accepted names would later be cons ...
campaign.


Catalogues

With the advent of the increased light-gathering abilities of the telescope, many more stars became visible, far too many to all be given names. Instead, they have designations assigned to them by a variety of different
star catalogue A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the year ...
s. Older catalogues either assigned an arbitrary number to each object, or used a simple systematic naming scheme based on the constellation the star lies in, like the older
Ptolemy Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...
's Almagest in Greek from
150 150 may refer to: * 150 (number), a natural number * AD 150, a year in the 2nd century AD * 150 BC, a year in the 2nd century BC * 150 Regiment RLC * Combined Task Force 150 * 150 Nuwa, a main-belt asteroid * Chevrolet 150, an economy or fleet car ...
and
Al-Sufi ʿAbd al-Raḥmān al-Ṣūfī (; 7 December 90325 May 986) was a Persian astronomer. His work '' '' ("''The Book of Fixed Stars''"), written in 964, included both textual descriptions and illustrations. The Persian polymath Al-Biruni wrote th ...
's
Book of Fixed Stars ''The Book of Fixed Stars'' ( ', literally ''The Book of the Shapes of Stars'') is an Astronomy, astronomical text written by Abd al-Rahman al-Sufi (Azophi) around 964. Following Graeco-Arabic translation movement, the translation movement in the ...
in Arabic from 964. The variety of sky catalogues in use means that most bright stars have multiple designations. In 1540, the Italian astronomer
Piccolomini The House of Piccolomini (pronounced ) is the name of an Italian noble family, Patricians of Siena, who were prominent from the beginning of the 13th century until the 18th century. The family achieved the recognized titles of Pope of the Catho ...
released the book ''De le Stelle Fisse'' (On the Fixed Stars) which include star maps of 47 constellations where he numbered the stars in magnitude order using latin letters.


Bayer designation

The
Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...
s of about 1,500 brightest stars were first published in 1603. In this list, a star is identified by a lower-case letter of the Greek alphabet, followed by the Latin name of its parent constellation. The Bayer designation uses the possessive form of a constellation's name, which in almost every case ends in ''is'', ''i'' or ''ae''; ''um'' if the constellation's name is plural ''(see genitive case for constellations)''. In addition, a three-letter abbreviation is often used . Examples include Alpha Andromedae (''α And'') in the constellation of Andromeda, Alpha Centauri (''α Cen''), in the constellation Centaurus, Alpha Crucis (''α Cru'') and Beta Crucis (''β Cru''), the two brightest stars in the constellation Crux, the Southern Cross, Epsilon Carinae (''ε Car'') in Carina, Lambda Scorpii (''λ Sco'') in Scorpius and Sigma Sagittarii (''σ Sgr'') in Sagittarius. After all twenty-four Greek letters have been assigned, upper and lower case Latin letters are used, such as for A Centauri (''A Cen''), D Centauri (''D Cen''), G Scorpii (''G Sco''),
P Cygni P Cygni (34 Cygni) is a variable star in the constellation Cygnus. The designation "P" was originally assigned by Johann Bayer in '' Uranometria'' as a nova. Located about 5,300 light-years (1,560 parsecs) from Earth, it is a hypergian ...
(''P Cyg''), b Sagittarii (''b Sgr''), d Centauri (''d Cen'') and s Carinae (''s Car''). As the resolving power of telescopes increased, numerous objects that were thought to be a single object were found to be optical
star system A star system or stellar system is a small number of stars that orbit each other, bound by gravity, gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally calle ...
s that were too closely spaced in the sky to be discriminated by the human eye. This led to a third iteration, where numeric superscripts were added to distinguish those previously unresolved stars. Examples include Theta Sagittarii (''θ Sgr'') later distinguished as Theta¹ Sagittarii (''θ¹ Sgr'') and Theta² Sagittarii (''θ² Sgr''), each being their own (physical) star system with two and three stars, respectively.


Flamsteed designation

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the 88 modern constellations, modern constellations visible from southern England. They are named after John Flamsteed, au ...
s consist of a number and the Latin genitive of the constellation the star lies in. Examples include
51 Pegasi 51 Pegasi (abbreviated 51 Peg), formally named Helvetios , is a Sun-like star located from Earth in the constellation of Pegasus. It was the first main-sequence star found to have an exoplanet (designated 51 Pegasi b, officially named ...
and
61 Cygni 61 Cygni is a binary star system in the constellation Cygnus (constellation), Cygnus, consisting of a pair of K-type main-sequence star, K-type dwarf stars that orbit each other in a period of about 659 years. Of apparent magnitu ...
. About 2,500 stars are catalogued. They are commonly used when no Bayer designation exists, or when the Bayer designation uses numeric superscripts such as in Rho¹ Cancri. In this case, the simpler Flamsteed designation,
55 Cancri 55 Cancri is a binary star system located 41 light-years away from the Sun in the zodiac constellation of Cancer. It has the Bayer designation Rho1 Cancri (ρ1 Cancri); ''55 Cancri'' is the Flamsteed designation (abbrev ...
, is often preferred.


Modern catalogues

Most modern catalogues are generated by computers, using high-resolution, high-sensitivity telescopes, and as a result describe very large numbers of objects. For example, the Guide Star Catalog II has entries on over 998 million distinct astronomical objects. Objects in these catalogs are typically located with very high resolution, and assign designations to these objects based on their position in the sky. An example of such a designation is ''SDSSp J153259.96−003944.1'', where the initialism ''SDSSp'' indicates that the designation is from the "
Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...
preliminary objects", and the other characters indicate
celestial coordinates In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points available to a situated observer (e. ...
(
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...
'J',
right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...
153259.96,
declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...
−00°39′44.1″).


Variable stars

Variable stars are assigned designations in a variable star scheme that is based on a variation of the
Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...
format, with an identifying label preceding the
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
genitive of the name of the
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
in which the star lies. Such designations mark them as variable stars. Examples include
R Cygni R Cygni is a variable star of the Mira type in the constellation Cygnus, less than 4' from θ Cygni. This is a red giant star on the asymptotic giant branch located around 2,200 light years away. It is an S-type star ranging betwee ...
, RR Lyrae, and V1331 Cygni. The
International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
delegates the task to the
Sternberg Astronomical Institute The Sternberg Astronomical Institute, or GAISh, is a research institution in Moscow, Russia, a division of Moscow State University. In Russian it is named or , respectively. The institute is named after astronomer Pavel Karlovich Shternberg. It wa ...
in Moscow, Russia.


Compact stars


Pulsars

Pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...
s such as
PSR J0737-3039 PSR may refer to: Organizations * Pacific School of Religion, Berkeley, California, US * Palestinian Center for Policy and Survey Research * Payment Systems Regulator in the United Kingdom * Physicians for Social Responsibility, US Political p ...
, are designated with a "PSR" prefix, that stands for ''Pulsating Source of Radio''. The prefix is followed by the pulsar's
right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...
and degrees of
declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...
. The right ascension is also prefixed with a "J" ( Julian epoch) or a "B" ( Besselian Epochs) used prior to 1993, as in
PSR B1257+12 PSR B1257+12, alternatively designated PSR J1300+1240, is a millisecond pulsar, from the Sun, in the constellation Virgo, rotating at about 161 times per second (faster than the blade of a blender). It is also named Lich, after a powerf ...
.


Black holes

Black holes have no consistent naming conventions.
Supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...
s receive the designation of the galaxy whose core they reside in. Examples are NGC 4261,
NGC 4151 NGC 4151 is an intermediate spiral galaxy, intermediate spiral Seyfert galaxy with weak inner ring structure located from Earth in the constellation Canes Venatici. The galaxy was first mentioned by William Herschel on March 17, 1787; it was on ...
and M31, which derive their designation from the ''
New General Catalogue The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxy, galaxies, star cluste ...
'' and the list of ''
Messier objects The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ' (''Catalogue of Nebulae and Star Clusters''). Because Messier was interested only in finding comets, he created a list of thos ...
''. Other black holes, such as
Cygnus X-1 Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus and was the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the ...
– a highly likely
stellar black hole A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a star. They have masses ranging from about 5 to several tens of solar masses. They are the remnants of supernova explosions, which may be ...
, are cataloged by their constellation and the order in which they were discovered. A large number of black holes are designated by their position in the sky and prefixed with the instrument or survey that discovered them. Examples are (where SDSS stands for
Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...
), and RX J1131−1231, observed by the
Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources ...
.


Supernovae

Supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...
discoveries are reported to the IAU's ''
Central Bureau for Astronomical Telegrams The Central Bureau for Astronomical Telegrams (CBAT) is an official international clearing house for information relating to transient astronomical events. The CBAT collects and distributes information on comets, natural satellites, novae, mete ...
'' and are automatically given a provisional designation based on the co-ordinates of the discovery. Historically, when supernovae are identified as belonging to a "type", CBAT has also published circulars with assigned year–letter designations, and discovery details. A supernova's permanent designation is formed by the standard prefix "SN", the year of discovery, and a suffix composed of one to three letters of the Latin alphabet. The first 26 supernovae of the year receive a capital letter from ''A'' to ''Z''. Subsequent supernovae of that year are designated with pairs of lower-case letters from "aa" to "az", and then continuing with "ba" until "zz". Then come "aaa", "aab", and so on (this first occurred in 2015-2016). For example, the prominent SN 1987A, was the first one to be observed in 1987, while
SN 2023ixf __NOTOC__ SN 2023ixf was a Type II-L (core collapse) supernova located 21 million light years away from Earth in the Pinwheel Galaxy in the constellation of Ursa Major. It was one of the brightest core collapse supernova to have occurred in the ...
was one of the brightest ever observed in recent times. Several thousand supernovae have been reported since 1885. In recent years, several supernova discovery projects have retained their more distant supernova discoveries for in-house follow-up, and not reported them to CBAT. Starting in 2015, CBAT has scaled back its efforts to publish assigned designations of typed supernovae: By September 2014, CBAT had published names and details of 100 supernovae discovered in that year. By September 2015, CBAT had only published names of 20 supernovae discovered in that year. The
Astronomer's Telegram ''The Astronomer's Telegram'' (''ATel'') is an internet-based short-notice publication service for quickly disseminating information on new astronomical observations. Examples include Gamma ray bursts, gamma-ray bursts, gravitational microlensin ...
provides some surrogate services independent from CBAT. Four historical supernovae are known simply by the year they occurred: SN 1006 (the brightest stellar event ever recorded), SN 1054 (of which the remnant is the
Crab Nebula The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus (constellation), Taurus. The common name comes from a drawing that somewhat resembled a crab with arm ...
and the
Crab Pulsar The Crab Pulsar (PSR B0531+21 or Baade's Star) is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054.
), SN 1572 (''Tycho's Nova''), and SN 1604 (''Kepler's Star''). Since 1885, the letter-suffixes are explicitly assigned, regardless whether only one supernova is detected during the entire year (although this has not occurred since 1947). Driven by advances in technology and increases in observation time in the early 21st century, hundreds of supernovae were reported every year to the IAU, with more than 500 catalogued in 2007. Since then, the number of newly discovered supernovae has increased to thousands per year, for example almost 16,000 supernovae observations were reported in 2019, more than 2,000 of which were named by CBAT.


Novae


Constellations

The sky was divided into
constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...
s by historic astronomers, according to perceived patterns in the sky. At first, only the shapes of the patterns were defined, and the names and numbers of constellations varied from one star map to another. Despite being scientifically meaningless, they do provide useful reference points in the sky for human beings, including astronomers. In 1930, the boundaries of these constellations were fixed by
Eugène Joseph Delporte Eugène Joseph Delporte (10 January 1882 – 19 October 1955) was a Belgian astronomer born in Genappe. He discovered a total of sixty-six asteroids. Notable discoveries include 1221 Amor (which lent its name to the Amor asteroids) and ...
and adopted by the IAU, so that now every point on the
celestial sphere In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, ...
belongs to a particular constellation.


Galaxies

Like stars, most
galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...
do not have names. There are a few exceptions such as the
Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a Galaxy#Isophotal diameter, D25 isop ...
, the
Whirlpool Galaxy The Whirlpool Galaxy, also known as Messier 51a (M51a) or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classifie ...
, and others, but most simply have a catalog number. In the 19th century, the exact nature of galaxies was not yet understood, and the early catalogs simply grouped together
open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...
s,
globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...
s,
nebula A nebula (; or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regions, such as in the Pillars of Creation in ...
s, and galaxies: the
Messier catalog The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ' (''Catalogue of Nebulae and Star Clusters''). Because Messier was interested only in finding comets, he created a list of thos ...
has 110 in total. The Andromeda Galaxy is Messier object 31, or M31; the Whirlpool Galaxy is
M51 M51 or M-51 may refer to: * M-51 (Michigan highway), a state highway in Michigan * M51 highway (Russia) * M51 (Cape Town), a Metropolitan Route in Cape Town, South Africa * M51 Skysweeper, an anti-aircraft gun * M51 MACI mine * M51 SLBM, a Frenc ...
. The
New General Catalogue The ''New General Catalogue of Nebulae and Clusters of Stars'' (abbreviated NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888. The NGC contains 7,840 objects, including galaxy, galaxies, star cluste ...
(NGC, J. L. E. Dreyer 1888) was much larger and contained nearly 8,000 objects, still mixing galaxies with nebulas and star clusters.


Planets

The brightest
planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...
s in the sky have been named from ancient times. The scientific names are taken from the names given by the Romans: Mercury,
Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...
,
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
,
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
, and
Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...
. Our own planet is usually named in English as
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
, or the equivalent in the language being spoken (for instance, two astronomers speaking
French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...
would call it ''la Terre''). However, it is only recently in human history that it has been thought of as a planet. Earth, when viewed as a planet, is sometimes also called by its Latin scientific conventional name ''
Terra Terra may often refer to: * Terra (mythology), primeval Roman goddess * An alternate name for planet Earth, as well as the Latin name for the planet Terra may also refer to: Geography Astronomy * Terra (satellite), a multi-national NASA scient ...
'', this name is especially prevalent in science fiction where the adjective "terran" is also used in the way which "Lunar" or "Jovian" is for Earth's moon or Jupiter. The Latin convention derives from the use of that language as an international scientific language by the first modern astronomers like Copernicus, Kepler, Galileo, Newton and others and was used for a long time. This is why the later discovered bodies were also named accordingly. Two more bodies that were discovered later, and considered planets when discovered, are still generally considered planets now: *
Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...
, discovered by
William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...
in 1781 *
Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...
, discovered by
Johann Gottfried Galle Johann Gottfried Galle (9 June 1812 – 10 July 1910) was a German astronomer from Radis, Germany, at the Berlin Observatory who, on 23 September 1846, with the assistance of student Heinrich Louis d'Arrest, was the first person to view the p ...
in 1846 (based on prediction by
Urbain Le Verrier Urbain Jean Joseph Le Verrier (; 11 March 1811 – 23 September 1877) was a French astronomer and mathematician who specialized in celestial mechanics and is best known for predicting the existence and position of Neptune using only mathematics. ...
) These were given names from Greek or Roman myth, to match the ancient planet names—but only after some controversy. For example, Sir William Herschel discovered Uranus in 1781, and originally called it ''Georgium Sidus'' (George's Star) in honour of King
George III of the United Kingdom George III (George William Frederick; 4 June 173829 January 1820) was King of Great Britain and Ireland from 25 October 1760 until his death in 1820. The Acts of Union 1800 unified Great Britain and Ireland into the United Kingdom of Great ...
. French astronomers began calling it Herschel before German
Johann Bode Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career Bo ...
proposed the name Uranus, after the Greek god. The name "Uranus" did not come into common usage until around 1850. Starting in 1801,
asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
s were discovered between Mars and Jupiter. The first few ( Ceres,
Pallas Pallas may refer to: Astronomy * 2 Pallas asteroid ** Pallas family, a group of asteroids that includes 2 Pallas * Pallas (crater), a crater on Earth's moon Mythology * Pallas (Giant), a son of Uranus and Gaia, killed and flayed by Athena * Pa ...
,
Juno Juno commonly refers to: *Juno (mythology), the Roman goddess of marriage and queen of the gods * ''Juno'' (film), the 2007 film Juno may also refer to: Arts, entertainment and media Fictional characters *Juno, a character in the book ''Juno of ...
, Vesta) were initially considered planets. As more and more were discovered, they were soon stripped of their planetary status. On the other hand,
Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...
was considered to be a planet at the time of its discovery in 1930, as it was found beyond Neptune. Following this pattern, several hypothetical bodies were given names: Vulcan for a planet within the orbit of Mercury; Phaeton for a planet between Mars and Jupiter that was believed to be the precursor of the asteroids;
Themis In Greek mythology and religion, Themis (; ) is the goddess and personification of justice, divine order, law, and custom. She is one of the twelve Titan children of Gaia and Uranus, and the second wife of Zeus. She is associated with oracles a ...
for a moon of Saturn; and
Persephone In ancient Greek mythology and Ancient Greek religion, religion, Persephone ( ; , classical pronunciation: ), also called Kore ( ; ) or Cora, is the daughter of Zeus and Demeter. She became the queen of the Greek underworld, underworld afte ...
, and several other names, for a trans-Plutonian planet. Derived from
Classical mythology Classical mythology, also known as Greco-Roman mythology or Greek and Roman mythology, is the collective body and study of myths from the ancient Greeks and ancient Romans. Mythology, along with philosophy and political thought, is one of the m ...
, these names are only considered standard in
Western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...
discussion of the planets. Astronomers in societies that have other traditional names for the planets may use those names in scientific discourse. For instance, IAU does not disapprove of astronomers discussing Jupiter in
Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...
using the traditional Arabic name for the planet, ''Al-Mushtarīy''. Some sixty years after the discovery of Pluto, a large number of large
trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (AU). ...
s began to be discovered. Under the criteria of classifying these
Kuiper belt The Kuiper belt ( ) is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times ...
objects (KBOs), it became dubious whether Pluto would have been considered a planet had it been discovered in the 1990s. Its mass is now known to be much smaller than once thought and, with the discovery of Eris, it is simply one of the two largest known trans-Neptunian objects. In 2006, Pluto was therefore reclassified into a different class of astronomical bodies known as
dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...
s, along with Eris and others.


Exoplanets

Currently, according to the IAU, there is no agreed upon system for designating
exoplanet An exoplanet or extrasolar planet is a planet outside the Solar System. The first confirmed detection of an exoplanet was in 1992 around a pulsar, and the first detection around a main-sequence star was in 1995. A different planet, first det ...
s (planets orbiting other stars). The process of naming them is organized by the IAU Executive Committee Working Group Public Naming of Planets and Planetary Satellites. The scientific nomenclature for the designations usually consists of a proper noun or abbreviation that often corresponds to the star's name, followed by a lowercase letter (starting with 'b'), like
51 Pegasi b 51 Pegasi b, officially named Dimidium (), is an extrasolar planet approximately away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the Sun-like 51 Pegasi, and marked a breakthr ...
. The lowercase lettering style is drawn from the IAU's long-established rules for naming binary and multiple star systems. A primary star, which is brighter and typically bigger than its companion stars, is designated by a capitalized A. Its companions are labelled B, C, and so on. For example,
Sirius Sirius is the brightest star in the night sky. Its name is derived from the Greek word (Latin script: ), meaning 'glowing' or 'scorching'. The star is designated  Canis Majoris, Latinized to Alpha Canis Majoris, and abbr ...
, the brightest star in the sky, is actually a double star, consisting of the naked-eye visible Sirius A and its dim white-dwarf companion
Sirius B Sirius is the brightest star in the night sky. Its name is derived from the Greek word (Latin script: ), meaning 'glowing' or 'scorching'. The star is designated  Canis Majoris, Latinized to Alpha Canis Majoris, and abbre ...
. The first exoplanet tentatively identified around the second brightest star in the triple star system
Alpha Centauri Alpha Centauri (, α Cen, or Alpha Cen) is a star system in the southern constellation of Centaurus (constellation), Centaurus. It consists of three stars: Rigil Kentaurus (), Toliman (), and Proxima Centauri (). Proxima Centauri ...
is accordingly called Alpha Centauri Bb. If an exoplanet orbits both of the stars in a binary system, its name can be, for example, Kepler-34(AB) b.


Natural satellites

Earth's natural satellite is simply known as the
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
, or the equivalent in the language being spoken (for instance, two astronomers speaking
French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...
would call it ''la Lune''). English-language science fiction often adopts the Latin name "Luna" while using the English "Moon" as a term for natural satellites in general in order to better distinguish the wider concept from any specific example. Natural satellites of other planets are generally named after mythological figures related to their parent body's namesake, such as Phobos and
Deimos Deimos, a Greek word for ''dread'', may refer to: In general * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites Fictional characters * Deimos (comi ...
, the twin sons of
Ares Ares (; , ''Árēs'' ) is the List of Greek deities, Greek god of war god, war and courage. He is one of the Twelve Olympians, and the son of Zeus and Hera. The Greeks were ambivalent towards him. He embodies the physical valor necessary for ...
(Mars), or the
Galilean moons The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede (moon), Ganymede, Callisto (moon), Callisto, Io (moon), Io, and Europa (moon), Europa. They are the most apparent m ...
of Io,
Europa Europa may refer to: Places * Europa (Roman province), a province within the Diocese of Thrace * Europa (Seville Metro), Seville, Spain; a station on the Seville Metro * Europa City, Paris, France; a planned development * Europa Cliffs, Alexan ...
, Ganymede, and
Callisto CALLISTO (''Cooperative Action Leading to Launcher Innovation in Stage Toss-back Operations'') is a reusable VTVL Prototype, demonstrator propelled by a small 40 kN Japanese LOX-LH2 rocket engine. It is being developed jointly by the CNES, French ...
, four consorts of
Zeus Zeus (, ) is the chief deity of the List of Greek deities, Greek pantheon. He is a sky father, sky and thunder god in ancient Greek religion and Greek mythology, mythology, who rules as king of the gods on Mount Olympus. Zeus is the child ...
(Jupiter). Satellites of Uranus are instead named after characters from works by
William Shakespeare William Shakespeare ( 23 April 1564 – 23 April 1616) was an English playwright, poet and actor. He is widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's nation ...
or
Alexander Pope Alexander Pope (21 May 1688 Old Style and New Style dates, O.S. – 30 May 1744) was an English poet, translator, and satirist of the Age of Enlightenment, Enlightenment era who is considered one of the most prominent English poets of the early ...
, such as
Umbriel Umbriel () is the third-largest moon of Uranus. It was discovered on October 24, 1851, by William Lassell at the same time as neighboring moon Ariel. It was named after a character in Alexander Pope's 1712 poem '' The Rape of the Lock''. Umb ...
or Titania. When
natural satellite A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are colloquially referred to as moons, a deriv ...
s are first discovered, they are given provisional designations such as "
S/2010 J 2 Jupiter LII, originally known as , is a natural satellite of Jupiter. It was discovered by Christian Veillet in 2010. It received its permanent number in March 2015. CBET "4075: 20150307: Satellites of Jupiter", March 7, 2015. It takes 1.69 yea ...
" (the 2nd new satellite of Jupiter discovered in 2010) or " S/2003 S 1" (the 1st new satellite of Saturn discovered in 2003). The initial "S/" stands for "satellite", and distinguishes from such prefixes as "D/", "C/", and "P/", used for
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s. The designation "R/" is used for planetary rings. These designations are sometimes written like "S/2003 S1", dropping the second space. The letter following the category and year identifies the planet (Jupiter, Saturn, Uranus, Neptune; although no occurrence of the other planets is expected, Mars and Mercury are disambiguated through the use of Hermes for the latter).
Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of Trans-Neptunian object, bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Su ...
was designated by P prior to its recategorization as a
dwarf planet A dwarf planet is a small planetary-mass object that is in direct orbit around the Sun, massive enough to be hydrostatic equilibrium, gravitationally rounded, but insufficient to achieve clearing the neighbourhood, orbital dominance like the ...
. When the object is found around a minor planet, the identifier used is the latter's number in parentheses. Thus, Dactyl, the moon of
243 Ida 243 Ida is an asteroid in the Koronis family of the asteroid belt. It was discovered on 29 September 1884 by Austrian astronomer Johann Palisa at Vienna Observatory and named after Ida (nurse of Zeus), a nymph from Greek mythology. Later telesc ...
, was at first designated " S/1993 (243) 1". Once confirmed and named, it became (243) Ida I Dactyl. Similarly, the fourth satellite of Pluto, Kerberos, discovered after Pluto was categorized as a dwarf planet and assigned a minor planet number, was designated S/2011 (134340) 1 rather than S/2011 P 1, though the ''
New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...
'' team, who disagreed with the dwarf planet classification, used the latter. * H = Mercury (Hermes) * V =
Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...
* E =
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
* M =
Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
* J =
Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...
* S =
Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...
* U =
Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...
* N =
Neptune Neptune is the eighth and farthest known planet from the Sun. It is the List of Solar System objects by size, fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet. It is 17 t ...
After a few months or years, when a newly discovered satellite's existence has been confirmed and its orbit computed, a permanent name is chosen, which replaces the "S/" provisional designation. However, in the past, some satellites remained unnamed for surprisingly long periods after their discovery. See
Naming of moons The naming of moons has been the responsibility of the International Astronomical Union's committee for Planetary System Nomenclature since 1973. That committee is known today as the Planetary nomenclature, Working Group for Planetary System Nomenc ...
for a history of how some of the major satellites got their current names. The Roman numbering system arose with the very first discovery of natural satellites other than Earth's:
Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...
referred to the
Galilean moons The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter. They are, in descending-size order, Ganymede (moon), Ganymede, Callisto (moon), Callisto, Io (moon), Io, and Europa (moon), Europa. They are the most apparent m ...
as I through IV (counting from Jupiter outward), in part to spite his rival
Simon Marius Simon Marius ( Latinized form of Simon Mayr; 10 January 1573 – 5 January 1625) was a German astronomer. He was born in Gunzenhausen, near Nuremberg, but spent most of his life in the city of Ansbach. He is best known for being among the first ...
, who had proposed the names now adopted, after his own proposal to name the bodies after members of the
Medici family The House of Medici ( , ; ) was an Italian banking family and political dynasty that first consolidated power in the Republic of Florence under Cosimo de' Medici and his grandson Lorenzo "the Magnificent" during the first half of the 15th ...
failed to win currency. Similar numbering schemes naturally arose with the discovery of moons around Saturn and Mars. Although the numbers initially designated the moons in orbital sequence, new discoveries soon failed to conform with this scheme (e.g. "Jupiter V" is Amalthea, which orbits closer to Jupiter than does Io). The unstated convention then became, at the close of the 19th century, that the numbers more or less reflected the order of discovery, except for prior historical exceptions (see the
Timeline of discovery of Solar System planets and their moons The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery (multiple dates occur when the moments o ...
).


Geological and geographical features

In addition to naming planets and satellites themselves, the individual geological and geographical features such as craters, mountains, and volcanoes, on those planets and satellites also need to be named. In the early days, only a very limited number of features could be seen on other Solar System bodies other than the
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
. Craters on the
Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
could be observed with even some of the earliest telescopes, and 19th-century telescopes could make out some features on Mars. Jupiter had its famous
Great Red Spot The Great Red Spot is a persistent high-pressure area, high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm that is the largest in the Solar System. It is the most recognizable feature on Jupiter, owing to its red-o ...
, also visible through early telescopes. In 1919, the IAU was formed, and it appointed a committee to regularize the chaotic lunar and Martian nomenclatures then current. Much of the work was done by
Mary Adela Blagg Mary Adela Blagg (17 May 1858 – 14 April 1944) was an English astronomer and was elected a fellow of the Royal Astronomical Society in 1916. She is noted for her work on selenography and variable stars. Early life and education Blagg ...
, and the report ''Named Lunar Formations'' by Blagg and Muller (1935), was the first systematic listing of lunar nomenclature. Later, "The System of Lunar Craters, quadrants I, II, III, IV" was published, under the direction of
Gerard P. Kuiper Gerard Peter Kuiper ( ; born Gerrit Pieter Kuiper, ; 7 December 1905 – 23 December 1973) was a Dutch-American astronomer, planetary scientist, selenographer, author and professor. The Kuiper belt is named after him. Kuiper is consi ...
. These works were adopted by the IAU and became the recognized sources for lunar nomenclature. The Martian nomenclature was clarified in 1958, when a committee of the IAU recommended for adoption the names of 128
albedo feature In planetary geology, an albedo feature is a large area on the surface of a planet (or other Solar System body) which shows a contrast in brightness or darkness (albedo) with adjacent areas. Historically, albedo features were the first (and usu ...
s (bright, dark, or colored) observed through ground-based telescopes (IAU, 1960). These names were based on a system of nomenclature developed in the late 19th century by the Italian astronomer Giovanni V. Schiaparelli (1879) and expanded in the early 20th century by Eugene M. Antoniadi (1929), a Greek-born astronomer working at
Meudon Meudon () is a French Communes of France, commune located in the Hauts-de-Seine Departments of France, department in the Île-de-France Regions of France, region, on the left bank of the Seine. It is located from the Kilometre Zero, center of P ...
, France. However, the age of
space probe Uncrewed spacecraft or robotic spacecraft are spacecraft without people on board. Uncrewed spacecraft may have varying levels of autonomy from human input, such as remote control, or remote guidance. They may also be autonomous, in which th ...
s brought high-resolution images of various Solar System bodies, and it became necessary to propose naming standards for the features seen on them.


Minor planets

Initially, the names given to
minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
s followed the same pattern as the other planets: names from Greek or Roman myths, with a preference for female names. With the discovery in 1898 of the first body found to cross the orbit of Mars, a different choice was deemed appropriate, and
433 Eros 433 Eros is a stony asteroid of the Amor group, and the first discovered, and second-largest near-Earth object. It has an elongated shape and a volume-equivalent diameter of approximately . Visited by the NEAR Shoemaker space probe in 1998, ...
was chosen. This started a pattern of female names for
main-belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...
bodies and male names for those with unusual orbits. As more and more discoveries were made over the years, this system was eventually recognized as being inadequate and a new one was devised. Currently, the responsibility for naming minor planets lies with the ''Working Group Small Bodies Nomenclature'' (WGSBN, originally the ''Committee Small Bodies Nomenclature'', CSBN, and before that the ''Minor Planet Names Committee'', MPNC), which is composed of 15 members, 11 of whom are voting members, while the other four are representatives for the
Working Group for Planetary System Nomenclature The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
, the
Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Funct ...
, as well as the
IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
President and General Secretary. Minor planets observed over at least two nights and which cannot be identified with an existing celestial object, are initially assigned provisional designations (containing the year and the sequential order of discovery within that year) by the Minor Planet Center. When enough observations of the same object are obtained to calculate a reliable orbit, a sequential number is assigned by the Minor Planet Center to the
minor-planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...
. After the designation is assigned, the discoverer is given an opportunity to propose a name, which, if accepted by the IAU, replaces the provisional designation. Thus for instance, was given the name Ixion and is now called 28978 Ixion. The name becomes official after its publication in the ''WGSBN Bulletin'' with a brief citation explaining its significance. This may be a few years after the initial sighting, or in the case of "lost" asteroids, it may take several decades before they are spotted again and finally assigned a designation. If a minor planet remains unnamed ten years after it has been given a designation, the right to name it is given also to identifiers of the various apparitions of the object, to discoverers at apparitions other than the official one, to those whose observations contributed extensively to the orbit determination, or to representatives of the observatory at which the official discovery was made. The WGSBN has the right to act on its own in naming a minor planet, which often happens when the number assigned to the body is an integral number of thousands. In recent years, automated search efforts such as
LINEAR In mathematics, the term ''linear'' is used in two distinct senses for two different properties: * linearity of a '' function'' (or '' mapping''); * linearity of a '' polynomial''. An example of a linear function is the function defined by f(x) ...
or
LONEOS Lowell Observatory Near-Earth-Object Search (LONEOS) was a project designed to discover asteroids and comets that orbit near the Earth. The project, funded by NASA, was directed by astronomer Ted Bowell of Lowell Observatory in Flagstaff, Ariz ...
have discovered so many thousands of new asteroids that the WGSBN has officially limited naming to a maximum of two names per discoverer every two months. Thus, the overwhelming majority of asteroids currently discovered are not assigned formal names. Under IAU rules, names must be pronounceable, preferably one word (such as
5535 Annefrank 5535 Annefrank ( ), provisional designation , is a stony Florian asteroid and suspected contact binary from the inner asteroid belt, approximately 4.5 kilometers in diameter. It was used as a target to practice the flyby technique that the '' S ...
), although exceptions are possible (such as 9007 James Bond), and since 1982, names are limited to a maximum of 16 characters, including spaces and hyphens. (This rule was violated once for the comet-asteroid
4015 Wilson–Harrington 4015 Wilson–Harrington is an active asteroid known both as comet 107P/Wilson–Harrington and as asteroid 4015 Wilson–Harrington. It passed from Earth on 20 July 2022 and then passed perihelion (closest approach to the Sun) on 24 August 2 ...
, whose name has 17 characters; this is because it had already been named as a comet before being rediscovered as an asteroid.) Letters with
diacritic A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word ''diacrit ...
s are accepted, although in English the diacritical marks are usually omitted in everyday usage.
4090 Říšehvězd 4090 Říšehvězd, provisional designation , is a stony asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered by Czech astronomer Antonín Mrkos at Kleť Observatory on 2 September 1986 ...
is an asteroid with the most diacritics (four). Military and political leaders are unsuitable unless they have been dead for at least 100 years. Names of pet animals are discouraged, but there are some from the past. Names of people, companies or products known only for success in business are not accepted, nor are citations that resemble advertising. Whimsical names can be used for relatively ordinary asteroids (such as 26858 Misterrogers or
274301 Wikipedia 274301 Wikipedia, provisional designation , is a Vestian asteroid orbiting in the inner region of the asteroid belt, approximately in diameter. It was discovered on 25 August 2008 by astronomers at the Andrushivka Astronomical Observatory in ...
), but those belonging to certain dynamical groups are expected to follow more strictly defined naming schemes. *
Near-Earth object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
s (such as
1862 Apollo 1862 Apollo is a stony asteroid, approximately 1.5 kilometers in diameter, classified as a near-Earth object (NEO). It was discovered by German astronomer Karl Reinmuth at Heidelberg Observatory on 24 April 1932, but lost and not recovered unti ...
) receive mythological names, except those associated with creation or the underworld, while distant
Amor asteroid The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor . The orbital perihelion of these objects is close to, but greater than, the orbital aphelion of Earth (i.e., the objects do not cross Earth's orbit ...
(with
perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...
larger than 1.15  au) may receive non-mythical names. *
Jupiter trojan The Jupiter trojans, commonly called trojan asteroids or simply trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each Trojan (celestial body), trojan Libration point orbit, librat ...
s (objects in a 1:1
orbital resonance In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relation ...
with Jupiter) are named for characters of the legendary
Trojan War The Trojan War was a legendary conflict in Greek mythology that took place around the twelfth or thirteenth century BC. The war was waged by the Achaeans (Homer), Achaeans (Ancient Greece, Greeks) against the city of Troy after Paris (mytho ...
. Asteroids at
Lagrangian point In celestial mechanics, the Lagrange points (; also Lagrangian points or libration points) are points of equilibrium (mechanics), equilibrium for small-mass objects under the gravity, gravitational influence of two massive orbit, orbiting b ...
are named after Greek characters (such as 588 Achilles), whilst asteroids at are named after Trojans (such as
884 Priamus 884 Priamus is a large Jupiter trojan from the Trojan camp, approximately in diameter. It was discovered on 22 September 1917, by German astronomer Max Wolf at Heidelberg Observatory in southern Germany. The dark D-type asteroid is one of the ...
). Small Jupiter trojans with absolute magnitudes fainter than 12 (in the ''V'' band) can be named for
Olympic Olympic or Olympics may refer to Sports Competitions * Olympic Games, international multi-sport event held since 1896 ** Summer Olympic Games ** Winter Olympic Games * Ancient Olympic Games, ancient multi-sport event held in Olympia, Greece bet ...
athletes. *
Centaurs A centaur ( ; ; ), occasionally hippocentaur, also called Ixionidae (), is a creature from Greek mythology with the upper body of a human and the lower body and legs of a horse that was said to live in the mountains of Thessaly. In one version o ...
(such as
2060 Chiron 2060 Chiron is a ringed small Solar System body in the outer Solar System, orbiting the Sun between Saturn and Uranus. Discovered in 1977 by Charles Kowal, it was the first-identified member of a new class of objects now known as centaurs— ...
) crossing or approaching the orbit of a
giant planet A giant planet, sometimes referred to as a jovian planet (''Jove'' being another name for the Roman god Jupiter (mythology), Jupiter), is a diverse type of planet much larger than Earth. Giant planets are usually primarily composed of low-boiling ...
, but not in a stabilizing resonance are named for the creatures, part horse and part man, from Greek mythology. *
Neptune trojan Neptune trojans are bodies that orbit the Sun near one of the stable Lagrangian points of Neptune, similar to the trojans of other planets. They therefore have approximately the same orbital period as Neptune and follow roughly the same orbita ...
s (objects in a 1:1 orbital resonance with Neptune, such as
385571 Otrera 385571 Otrera, provisional designation , is a Neptune trojan leading Neptune's orbit in the outer Solar System. It was discovered by American astronomers Scott Sheppard and Chad Trujillo at Las Campanas Observatory on 16 October 2004. It measur ...
) are named for
Amazons The Amazons (Ancient Greek: ', singular '; in Latin ', ') were a people in Greek mythology, portrayed in a number of ancient epic poems and legends, such as the Labours of Hercules, Labours of Heracles, the ''Argonautica'' and the ''Iliad''. ...
, with no differentiation between objects in and . *
Plutino In astronomy, the plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the la ...
s (such as
90482 Orcus Orcus (minor-planet designation: 90482 Orcus) is a dwarf planet located in the Kuiper belt, with one large moon, Vanth. It has an estimated diameter of , comparable to the Inner Solar System dwarf planet Ceres. The surface of Orcus is relativ ...
) are named after mythological figures associated with the
underworld The underworld, also known as the netherworld or hell, is the supernatural world of the dead in various religious traditions and myths, located below the world of the living. Chthonic is the technical adjective for things of the underworld. ...
. * Other
trans-Neptunian object A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has an orbital semi-major axis of 30.1 astronomical units (AU). ...
s (such as
50000 Quaoar Quaoar ( minor-planet designation: 50000 Quaoar) is a ringed dwarf planet in the Kuiper Belt, a ring of many icy planetesimals beyond Neptune. It has an elongated ellipsoidal shape with an average diameter of , about half the size of the d ...
), including
classical Kuiper belt object A classical Kuiper belt object, also called a cubewano ( "QB1-o"), is a low-eccentricity Kuiper belt object (KBO) that orbits beyond Neptune and is not controlled by an orbital resonance with Neptune. Cubewanos have orbits with semi-major axe ...
s, are given mythological or mythic names (not necessarily from Greek or Roman mythology), particularly those associated with creation.


Comets

The names given to
comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...
s have followed several different conventions over the past two centuries. Before any systematic naming convention was adopted, comets were named in a variety of ways. The first one to be named was "
Halley's Comet Halley's Comet is the only known List of periodic comets, short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30) occurring after ...
" (now officially known as Comet Halley), named after
Edmond Halley Edmond (or Edmund) Halley (; – ) was an English astronomer, mathematician and physicist. He was the second Astronomer Royal in Britain, succeeding John Flamsteed in 1720. From an observatory he constructed on Saint Helena in 1676–77, Hal ...
, who had calculated its orbit. Similarly, the second known periodic comet,
Comet Encke Comet Encke , or Encke's Comet (official designation: 2P/Encke), is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PanSTARRS has ...
(formally designated 2P/Encke), was named after the astronomer, Johann Franz Encke, who had calculated its orbit rather than the original discoverer of the comet, Pierre Méchain. Other comets that bore the possessive include "Biela's Comet" (
3D/Biela Biela's Comet or Comet Biela (official designation: 3D/Biela) was a periodic Jupiter-family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela. It was subsequently observed ...
) and "Miss Herschel's Comet" ( 35P/Herschel–Rigollet, or Comet Herschel–Rigollet). Most bright (non-periodic) comets were referred to as 'The Great Comet Of...' the year in which they appeared. In the early 20th century, the convention of naming comets after their discoverers became common, and this remains today. A comet is named after its first independent discoverers, up to a maximum of three names, separated by hyphens. The IAU prefers to credit at most two discoverers, and it credits more than three discoverers only when "in rare cases where named lost comets are identified with a rediscovery that has already received a new name." In recent years, many comets have been discovered by instruments operated by large teams of astronomers, and in this case, comets may be named for the instrument (for example,
Comet IRAS–Araki–Alcock A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and ...
(C/1983 H1) was discovered independently by the
IRAS The Infrared Astronomical Satellite (Dutch language, Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a astronomical survey, survey of the entire night sky at infrared wavelengths. Launched on 25 Janu ...
satellite and amateur astronomers
Genichi Araki This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 num ...
and
George Alcock George Eric Deacon Alcock, MBE (28 August 1912, in Peterborough, Northamptonshire – 15 December 2000) was an English amateur astronomer. He was one of the most successful visual discoverers of novae and comets. George’s interest in astro ...
). Comet 105P/Singer Brewster, discovered by Stephen Singer-Brewster, should by rights have been named "105P/Singer-Brewster", but this could be misinterpreted as a joint discovery by two astronomers named Singer and Brewster, respectively, so the hyphen was replaced by a space. Go t
the journal search in the Astrophysics Data System
pick "Journal of the Association of Lunar and Planetary Observers", volume "33", page "26". It's not in the list of abstracts, you have to check the page thumbnails.
The spaces, apostrophes and other characters in discoverer names are preserved in comet names, like
32P/Comas Solà 32P/Comas Solà is a periodic comet with a current orbital period of 9.7 years around the Sun. Observational history ''32P/Comas Solà'' was discovered November 5, 1926, by Josep Comas Solà. As part of his work on asteroids for the Fabra Obs ...
,
6P/d'Arrest 6P/d'Arrest (also known as d'Arrest's Comet or Comet d'Arrest) is a List of periodic comets, periodic Jupiter-family comet, Jupiter-family comet in the Solar System, orbiting between Mars and Jupiter. It passed from the Earth on August 12, 1976 ...
, 53P/Van Biesbroeck,
Comet van den Bergh (1974g) A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and ...
, 66P/du Toit, or 57P/du Toit–Neujmin–Delporte. Until 1994, the systematic naming of comets (the "Old Style") involved first giving them a provisional designation of the year of their discovery followed by a lower case letter indicating its order of discovery in that year (e.g. the first Comet Bennett is 1969i, the 9th comet discovered in 1969). In 1987, more than 26 comets were discovered, so the alphabet was used again with a "1" subscript, very much like what is still done with asteroids (an example is Comet Skorichenko–George, 1989e1). The record year was 1989, which went as high as 1989h1. Once an orbit had been established, the comet was given a permanent designation in order of time of
perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...
passage, consisting of the year followed by a
Roman numeral Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Numbers are written with combinations of letters from the Latin alphabet, ea ...
. For example, Comet Bennett (1969i) became 1970 II. Increasing numbers of comet discoveries made this procedure difficult to operate, and in 2003 the IAU's Committee on Small Body Nomenclature approved a new naming system,IAU Comet-naming Guidelines
, Committee on Small Body Nomenclature of Division III of the IAU
and in its 1994 General Assembly the IAU approved a new designation system that entered into force in 1995 January 1. Comets are now designated by the year of their discovery followed by a letter indicating the half-month of the discovery (A denotes the first half of January, B denotes the second half of January, C denotes the first half of February, D denotes the second half of February, and so on) and a number indicating the order of discovery. To exemplify, the fourth comet discovered in the second half of February 2006 would be designated 2006 D4. "I" and "Z" are not used when describing the half of a particular month the comet was discovered. Prefixes are also added to indicate the nature of the comet, with P/ indicating a periodic comet, C/ indicating a non-periodic comet, X/ indicating a comet for which no reliable orbit could be calculated (typically comets described in historical chronicles), D/ indicating a comet that has broken up or been lost, and A/ indicating an object at first thought to be a comet but later reclassified as an asteroid (C/2017 U1 became A/2017 U1, then finally 1I/ʻOumuamua). Objects on hyperbolic orbits that do not show cometary activity also receive an A/ designation (example: A/2018 C2, which became
C/2018 C2 (Lemmon) C/2018 C2 (Lemmon) is a hyperbolic comet (previously classified as A/2018 C2, a hyperbolic asteroid). It was first observed on 5 February 2018 by the Mount Lemmon Survey conducted at the Mount Lemmon Observatory near Tucson, Arizona, in the Unit ...
when cometary activity was detected). Periodic comets also have a number indicating the order of their discovery. Thus Bennett's Comet has the systematic designation C/1969 Y1. Halley's Comet, the first comet to be identified as periodic, has the systematic name 1P/1682 Q1.
Comet Hale–Bopp Comet Hale–Bopp (formally designated C/1995 O1) is a long-period comet that was one of the most widely observed of the 20th century and one of the brightest seen for many decades. Alan Hale (astronomer), Alan Hale and Thomas Bopp disc ...
's systematic name is C/1995 O1. The famous
Comet Shoemaker–Levy 9 Comet Shoemaker–Levy 9 ( formally designated D/1993 F2) was a comet that broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. ...
was the ninth periodic comet jointly discovered by
Carolyn Shoemaker Carolyn Jean Spellmann Shoemaker (June 24, 1929 – August 13, 2021) was an American astronomer and a co-discoverer of Comet Shoemaker–Levy 9, Comet Shoemaker–Levy 9. She discovered 32 comets (then a record for the most by an individu ...
,
Eugene Shoemaker Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997) was an American geologist. He co-discovered Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was telev ...
, and David Levy (the Shoemaker–Levy team has also discovered four non-periodic comets interspersed with the periodic ones), but its systematic name is D/1993 F2 (it was discovered in 1993 and the prefix "D/" is applied, because it was observed to crash into Jupiter). Some comets were first spotted as minor planets, and received a temporary designation accordingly before cometary activity was later discovered. This is the reason for such comets as ( Catalina 2) or (
Spacewatch The Spacewatch Project is an astronomical survey that specializes in the study of minor planets, including various types of asteroids and comets at University of Arizona telescopes on Kitt Peak near Tucson, Arizona. The Spacewatch Project has be ...
LINEAR In mathematics, the term ''linear'' is used in two distinct senses for two different properties: * linearity of a '' function'' (or '' mapping''); * linearity of a '' polynomial''. An example of a linear function is the function defined by f(x) ...
). The MPECs and HTML version of IAUCs, because of their telegraphic style, "flatten out" the subscripts, but the PDF version of IAUCsCompare th
HTML
an
PDF
versions of IAUC 8797: in the PDF version the designation P/ is written with a subscript.
and some other sources such as the Yamamoto Circulars and the Kometnyj Tsirkular use them.


See also

*
List of adjectivals and demonyms of astronomical bodies The adjectival forms of the names of astronomical bodies are not always easily predictable. Attested adjectival forms of the larger bodies are listed below, along with the two small Martian moons; in some cases they are accompanied by their demony ...
*
List of astronomical objects named after people This is a list of astronomical objects named after people. While topological features on Solar System bodies — such as craters, mountains, and valleys — are often named after famous or historical individuals, many stars and deep-sky objects a ...
*
List of basic astronomy topics The following Outline (list), outline is provided as an overview of and topical guide to astronomy: Astronomy – studies the universe beyond Earth, including its physical cosmology, formation and development, and the evolution, physics, chemis ...
*
List of brightest stars This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2.50 in visible light, measured using a ''V''-band filter in the UBV photometric system. St ...
*
List of minor planets The following is a list of minor planets in ascending numerical order. Minor planets are Small Solar System bodies, small bodies in the Solar System: asteroids, Distant minor planet, distant objects, and dwarf planets, but not comets. As of 2022 ...
(includes asteroids) *
NameExoWorlds NameExoWorlds (also known as IAU NameExoWorlds) were various projects managed by the International Astronomical Union (I.A.U.) to encourage names to be submitted for astronomical objects, notably exoplanets. The accepted names would later be cons ...
*
Planetary nomenclature Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. Since the invention of the ...
*
Proper names (astronomy) In ancient times, only the Sun and Moon, a few stars, and the most easily visible planets had names. Over the last few hundred years, the number of identified astronomical objects has risen from hundreds to over a billion, and more are discovered ...
*
Provisional designation in astronomy Provisional designation in astronomy is the astronomical naming conventions, naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation onc ...


Footnotes


References

*


External links


Cometary designation system
from ''Minor Planet Circulars'' 23803-4
Working Group Small Body Nomenclature

Dictionary of nomenclature of astronomical objects



IAU on Naming Astronomical Objects






from the Minor Planet Center
Who named the planets and who decides what to name them?
{{DEFAULTSORT:Astronomical Naming Conventions Astronomical nomenclature