Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern

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. It is in the direction of the fourth galactic quadrant, between Leo and

Boötes Boötes ( ) is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from , which comes from 'herder, herdsman' or 'plowman' (literally, 'o ...

, and it is visible in both hemispheres. Its name means "Berenice's Hair" in

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 ...

and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a

votive offering A votive offering or votive deposit is one or more objects displayed or deposited, without the intention of recovery or use, in a sacred place for religious purposes. Such items are a feature of modern and ancient societies and are generally ...

. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by

Gerardus Mercator Gerardus Mercator (; 5 March 1512 – 2 December 1594) was a Flemish people, Flemish geographer, cosmographer and Cartography, cartographer. He is most renowned for creating the Mercator 1569 world map, 1569 world map based on a new Mercator pr ...

and

Tycho Brahe Tycho Brahe ( ; ; born Tyge Ottesen Brahe, ; 14 December 154624 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations. He ...

. It is the only modern constellation named after a historic person. The constellation's major stars are

Alpha Alpha (uppercase , lowercase ) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter ''aleph'' , whose name comes from the West Semitic word for ' ...

Beta Beta (, ; uppercase , lowercase , or cursive ; or ) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Ancient Greek, beta represented the voiced bilabial plosive . In Modern Greek, it represe ...

, and Gamma Comae Berenices. They form a half square, along the diagonal of which run Berenice's imaginary tresses, formed by the Coma Star Cluster. The constellation's brightest star is Beta Comae Berenices, a 4.2- magnitude

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

star similar to the Sun. Coma Berenices contains the North Galactic Pole and one of the richest-known galaxy clusters, the Coma Cluster, part of the Coma Supercluster. Galaxy Malin 1, in the constellation, is the first-known giant low-surface-brightness galaxy.

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 ...

SN 1940B was the first scientifically observed (underway) type II supernova. FK Comae Berenices is the prototype of an eponymous class of variable stars. The constellation is the radiant of one

meteor shower A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at ext ...

, Coma Berenicids, which has one of the fastest meteor speeds, up to .

History

Coma Berenices has been recognized as an asterism since the

Hellenistic period In classical antiquity, the Hellenistic period covers the time in Greek history after Classical Greece, between the death of Alexander the Great in 323 BC and the death of Cleopatra VII in 30 BC, which was followed by the ascendancy of the R ...

(or much earlier, according to some authors), and is the only modern constellation named for an historic figure. It was introduced to Western astronomy during the third century BC by Conon of Samos, the court astronomer of Egyptian ruler Ptolemy III Euergetes, to honour Ptolemy's consort, Berenice II. Berenice vowed to sacrifice her long hair as a

if Ptolemy returned safely from battle during the Third Syrian War. Modern scholars are uncertain if Berenice made the sacrifice before or after Ptolemy's return; it was suggested that it happened after Ptolemy's return (around March–June or May 245 BC), when Conon presented the asterism jointly with scholar and poet

Callimachus Callimachus (; ; ) was an ancient Greek poet, scholar, and librarian who was active in Alexandria during the 3rd century BC. A representative of Ancient Greek literature of the Hellenistic period, he wrote over 800 literary works, most of which ...

during a public evening ceremony. In Callimachus' poem, '' Aetia'' (composed around that time), Berenice dedicated her tresses "to all the gods". In Poem 66, the Latin translation by the Roman poet

Catullus Gaius Valerius Catullus (; ), known as Catullus (), was a Latin neoteric poet of the late Roman Republic. His surviving works remain widely read due to their popularity as teaching tools and because of their personal or sexual themes. Life ...

, and in Hyginus' '' De Astronomica'', she dedicated her tresses to

Aphrodite Aphrodite (, ) is an Greek mythology, ancient Greek goddess associated with love, lust, beauty, pleasure, passion, procreation, and as her syncretism, syncretised Roman counterpart , desire, Sexual intercourse, sex, fertility, prosperity, and ...

and placed them in the temple of Arsinoe II (identified after Berenice's death with Aphrodite) at Zephyrium. According to ''De astronomica'', by the next morning the tresses had disappeared. Conon proposed that Aphrodite had placed the tresses in the sky as an acknowledgement of Berenice's sacrifice. Callimachus called the asterism ''plokamos Berenikēs'' or ''bostrukhon Berenikēs'' in Greek, translated into Latin as "Coma Berenices" by Catullus.

Hipparchus Hipparchus (; , ; BC) was a Ancient Greek astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hippar ...

and

Geminus Geminus of Rhodes (), was a Greek astronomer and mathematician, who flourished in the 1st century BC. An astronomy work of his, the ''Introduction to the Phenomena'', still survives; it was intended as an introductory astronomy book for students ...

also recognized it as a distinct constellation.

Eratosthenes Eratosthenes of Cyrene (; ; – ) was an Ancient Greek polymath: a Greek mathematics, mathematician, geographer, poet, astronomer, and music theory, music theorist. He was a man of learning, becoming the chief librarian at the Library of A ...

called it "Berenice's Hair" and " Ariadne's Hair", considering it part of the constellation Leo. Similarly,

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 ...

did not include it among his 48 constellations in the '' Almagest''; considering it part of Leo and calling it ''Plokamos''. Coma Berenices became popular during the 16th century. In 1515, a set of gores by Johannes Schöner labelled the asterism ''Trica'', "hair". In 1536 it appeared on a

celestial globe Celestial globes show the apparent positions of the stars in the sky. They omit the Sun, Moon, and planets because the positions of these bodies vary relative to those of the stars, but the ecliptic, along which the Sun moves, is indicated. ...

by Caspar Vopel, who is credited with the asterism's designation as a constellation. That year, it also appeared on a celestial map by Petrus Apianus as "Crines Berenices". In 1551, Coma Berenices appeared on a

with five Latin and Greek names: Cincinnus, ''caesaries'', ''πλόκαμος'', ''Berenicis crinis'' and Trica. Mercator's reputation as a cartographer ensured the constellation's inclusion on Dutch sky globes beginning in 1589.

, also credited with Coma's designation as a constellation, included it in his 1602 star catalogue. Brahe recorded fourteen stars in the constellation; Johannes Hevelius increased its number to twenty-one, and John Flamsteed to forty-three. Coma Berenices also appeared in Johann Bayer's 1603 '' Uranometria'', and a few other 17th-century celestial maps followed suit. Coma Berenices and the now-obsolete

Antinous Antinous, also called Antinoös, (; ; – ) was a Greek youth from Bithynia, a favourite and lover of the Roman emperor Hadrian. Following his premature death before his 20th birthday, Antinous was deified on Hadrian's orders, being worshippe ...

are considered the first post-Ptolemaic constellations depicted on a celestial globe. With Antinous, Coma Berenices exemplified a trend in astronomy in which globe- and map-makers continued to rely on the ancients for data. This trend ended at the turn of the 16th century with observations of the southern sky and the work of Tycho Brahe. Before the 18th century Coma Berenices was known in English by several names, including "Berenice's Bush" and "Berenice's periwig". The earliest-known English name, "Berenices haire", dates to 1601. By 1702 the constellation was known as Coma Berenices, and appears as such in the 1731 '' Universal Etymological English Dictionary''.

Non-Western astronomy

Coma Berenices was known to the Akkadians as Ḫegala. In

Babylonian astronomy Babylonian astronomy was the study or recording of celestial objects during the early history of Mesopotamia. The numeral system used, sexagesimal, was based on 60, as opposed to ten in the modern decimal system. This system simplified the ca ...

a star, known as ḪÉ.GÁL-''a''-''a'' (translated as "which is before it") or MÚL.ḪÉ.GÁL-''a''-''a'', is tentatively considered part of Coma Berenices. It was also argued that Coma Berenices appears in Egyptian Ramesside star clocks as ''sb3w ꜥš3w'', meaning "many stars". In Arabic astronomy Coma Berenices was known as ''Al-Dafira الضفيرة ("braid"),'' ''Al-Hulba'' ''الهلبة'' and ''Al-Thu'aba الذؤابة'' (both meaning "tuft"), the latter two are translations of the Ptolemaic ''Plokamos'', forming the tuft of the constellation Leo and including most of the Flamsteed-designated stars (particularly 12, 13, 14, 16, 17, 18 and 21 Comae Berenices). Al-Sufi included it in Leo. Ulugh Beg, however, regarded ''Al-Dafira'' as consisting of two stars, 7 and 23 Comae Berenices. R. H. Allen's '' Star Names'' gives the name ''Al Ḍafīrah'' to 15 = Gamma Comae Berenices. The North American Pawnee people depicted Coma Berenices as ten faint stars on a tanned elk-skin star map dated to at least the 17th century. In the South American Kalina mythology, the constellation was known as ''ombatapo'' (face). The constellation was also recognized by several Polynesian peoples. The people of

Tonga Tonga, officially the Kingdom of Tonga, is an island country in Polynesia, part of Oceania. The country has 171 islands, of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. accordin ...

had four names for Coma Berenices: ''Fatana-lua'', ''Fata-olunga'', ''Fata-lalo'' and ''Kapakau-o-Tafahi''. The Boorong people called the constellation ''Tourt-chinboiong-gherra'', and saw it as a small flock of birds drinking rainwater from a puddle in the crotch of a tree. The people of the Pukapuka atoll may have called it ''Te Yiku-o-te-kiole'', although sometimes this name is associated with

Ursa Major Ursa Major, also known as the Great Bear, is a constellation in the Northern Sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear", referring to and contrasting it with nearby Ursa M ...

Characteristics

Coma Berenices is bordered by Boötes to the east, Canes Venatici to the north, Leo to the west and Virgo to the south. Covering 386.5 square degrees and 0.937% of the night sky, it ranks 42nd of the 88 constellations by area. The three-letter abbreviation for the constellation, as adopted by 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 ...

in 1922, is "Com". The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 12 segments (''illustrated in infobox''). In the

equatorial coordinate system The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of astronomical object, celestial objects. It may be implemented in spherical coordinate system, spherical or Cartesian coordinate system, rect ...

, the

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 ...

coordinates of these borders lie between and , and the

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 ...

coordinates are between +13.30° and +33.31°. Coma Berenices is wholly visible to observers north of latitude 56°S. and the constellation's midnight

culmination In observational astronomy, culmination is the passage of a celestial object (such as the Sun, the Moon, a planet, a star, constellation or a deep-sky object) across the observer's local meridian. These events are also known as meridian tran ...

occurs on 2 April.

Features

Although it is not large, Coma Berenices contains one galactic supercluster, two galactic clusters, one star cluster and eight

Messier object 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 th ...

s (including several

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). These objects can be seen with minimal obscuration by dust because the constellation is not in the direction of the

galactic plane The galactic plane is the plane (geometry), plane on which the majority of a disk-shaped galaxy's mass lies. The directions perpendicular to the galactic plane point to the galactic poles. In actual usage, the terms ''galactic plane'' and ''galac ...

. Because of that, there are few

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 (except for the Coma Berenices Cluster, which dominates the northern part of the constellation), diffuse

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 ...

e or

planetary nebula A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to planets. The ...

e. Coma Berenices contains the North Galactic Pole at

and

(epoch

J2000.0 In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to pe ...

Stars

Brightest stars

Coma Berenices is not particularly bright, as none of its stars are brighter than fourth magnitude, although there are 66 stars brighter than or equal to

apparent magnitude Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), ...

6.5. The constellation's brightest star is Beta Comae Berenices (43 Comae Berenices in Flamsteed designation), at magnitude 4.2 and with a high

proper motion Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...

. In Coma Berenices' northeastern region, it is 29.95 ± 0.10

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s from Earth. A solar analog, it is a yellow-hued F-type main-sequence star with a spectral class of F9.5V B. Beta Comae Berenices is around 36% brighter,. See Table 10. and 15% more massive than the Sun, ''Note:'' see VizieR catalogu
J/ApJS/168/297
and with a radius 10% larger. The second-brightest star in Coma Berenices is the 4.3-magnitude, bluish Alpha Comae Berenices (42 Comae Berenices), with the

proper name A proper noun is a noun that identifies a single entity and is used to refer to that entity (''Africa''; ''Jupiter''; ''Sarah''; ''Walmart'') as distinguished from a common noun, which is a noun that refers to a class of entities (''continent, pl ...

Diadem, in the southeastern part of the constellation. Despite its Alpha

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 ...

, the star is dimmer than Beta Comae Berenices, being one of the cases where designation does not correspond to the brightest star. It is a double star, with the spectral classes of F5V and F6V. The star system is 58.1 ± 0.9 light-years from Earth. Gamma Comae Berenices (15 Comae Berenices) is an orange-hued giant star with a magnitude of 4.4 and a spectral class of K1III C. In the southwestern part of the constellation, it is 169 ± 2 light-years from Earth, Estimated to be around 1.79 times as massive as the Sun, it has expanded to around 10 times its radius.HD 108381
Accessed on line October 12, 2010. It is the brightest star in the Coma Star Cluster. With Alpha Comae Berenices and Beta Comae Berenices, Gamma Comae Berenices forms a 45-degree

isosceles triangle In geometry, an isosceles triangle () is a triangle that has two Edge (geometry), sides of equal length and two angles of equal measure. Sometimes it is specified as having ''exactly'' two sides of equal length, and sometimes as having ''at le ...

from which Berenice's imaginary tresses hang.

Star systems

The

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 of Coma Berenices include binary,

double Double, The Double or Dubble may refer to: Mathematics and computing * Multiplication by 2 * Double precision, a floating-point representation of numbers that is typically 64 bits in length * A double number of the form x+yj, where j^2=+1 * A ...

and triple stars. 21 Comae Berenices (sometimes called Kissin, but this name is shared with 23 Comae Berenices) is a close binary with nearly equal components and an orbital period of 26 years. The system is 272 ± 3 light-years away. The Coma Cluster contains at least eight

spectroscopic binaries A binary star or binary star system is a Star system, system of two stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved ...

, and the constellation has seven eclipsing binaries: CC, DD, EK, RW, RZ, SS and UX Comae Berenices. There are over thirty double stars in Coma Berenices, including 24 Comae Berenices with contrasting colors. Its primary is an orange-hued giant star with a magnitude of 5.0, 610 light-years from Earth, and its secondary is a blue-white-hued star with a magnitude of 6.6. Triple stars include 12 Comae Berenices, 17 Comae Berenices, KR Comae Berenices and Struve 1639.

Variable stars

Over 200

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

s are known in Coma Berenices, although many are obscure. Alpha Comae Berenices is a possible Algol variable. FK Comae Berenices, which varies from magnitude 8.14 to 8.33 over a period of 2.4 days, is the prototype for the FK Comae Berenices class of variable stars and the star in which the " flip-flop phenomenon" was discovered. FS Comae Berenices is a semi-regular variable, a red giant with a period of about two months whose magnitude varies between 6.1 and 5.3. R Comae Berenices is a Mira variable with a maximum magnitude of almost 7. There are 123 RR Lyrae variables in the constellation, with many in the M53 cluster. One of these stars, TU Comae Berenices, may have a binary system. The M100 galaxy contains about twenty

Cepheid variable A Cepheid variable () is a type of variable star that pulsates radially, varying in both diameter and temperature. It changes in brightness, with a well-defined stable period (typically 1–100 days) and amplitude. Cepheids are important cosmi ...

s, which were observed by the

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

. Coma Berenices also contains Alpha² Canum Venaticorum variables, such as 13 Comae Berenices and AI Comae Berenices. In 2019 scientists at Aryabhatta Research Institute of Observational Sciences announced the discovery of 28 new variable stars in Coma Berenices' globular cluster NGC 4147.

Supernovae

A number of

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 ...

e have been discovered in Coma Berenices. Four ( SN 1940B, SN 1969H, SN 1987E and SN 1999gs) were in the NGC 4725 galaxy, and another four were discovered in the M99 galaxy (NGC 4254): SN 1967H, SN 1972Q, SN 1986I and SN 2014L. Five were discovered in the M100 galaxy (NGC 4321): SN 1901B, SN 1914A, SN 1959E, SN 1979C and SN 2006X. SN 1940B, discovered on 5 May 1940, was the first observed type II supernova. SN 2005ap, discovered on 3 March 2005, is the second-brightest-known supernova to date with a peak absolute magnitude of about −22.7. Due to its great distance from Earth (4.7 billion light-years), it was not visible to the naked eye and was discovered telescopically. SN 1979C, discovered in 1979, retained its original

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

brightness for 25 years despite fading in visible light.

Other stars

Coma Berenices also contains the

neutron star A neutron star is the gravitationally collapsed Stellar core, core of a massive supergiant star. It results from the supernova explosion of a stellar evolution#Massive star, massive star—combined with gravitational collapse—that compresses ...

RBS 1223 and the

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 ...

PSR B1237+25. RBS 1223 is a member of the Magnificent Seven, a group of young neutron stars. In 1975, the first extra-solar source of extreme ultraviolet, the white dwarf HZ 43, was discovered in Coma Berenices. In 1995, there was a very rare outburst of the WZ Sagittae-type dwarf nova AL Comae Berenices. A June 2003 outburst from GO Comae Berenices, an SU Ursae Majoris-type dwarf nova, was photometrically observed.

Exoplanets

Coma Berenices has seven known

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. One, HD 108874 b, has Earth-like insolation. WASP-56 is a sun-like star of spectral type G6 and apparent magnitude 11.48 with a planet 0.6 the mass of

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 ...

that has a period of 4.6 days.

Star clusters

Coma Star Cluster

The Coma Star Cluster represents Berenice's sacrificed tresses and as a naked eye object has been known since antiquity, appearing in Ptolemy's '' Almagest''. It doesn't have a Messier or NGC designation, but is in the Melotte catalogue of open clusters (designated Melotte 111) and is also catalogued as Collinder 256. It is a large, diffuse

of about 50 stars ranging between magnitudes five and ten, including several of Coma Berenices' stars which are visible to the naked eye. The cluster is spread over a huge region (more than five degrees across) near Gamma Comae Berenices. It has such a large apparent size because it is relatively close, only 280 light-years or 86 parsecs away.

Globular clusters

M53 (NGC 5024) is a

which was discovered independently by Johann Elert Bode in 1775 and Charles Messier in February 1777;

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 ...

was the first to resolve it into stars. The magnitude-7.7 cluster is 56,000 light-years from Earth. Only 1° away is NGC 5053, a globular cluster with a sparser nucleus of stars. Its total luminosity is the equivalent of about 16,000 suns, one of the lowest luminosities of any globular cluster. It was discovered by William Herschel in 1784. NGC 4147 is a somewhat dimmer globular cluster, with a much-smaller apparent size and an apparent magnitude of 10.7.

Galaxies

Coma Supercluster

The Coma Supercluster, itself part of the Coma Filament, contains the

Coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to Nociception, respond normally to Pain, painful stimuli, light, or sound, lacks a normal Circadian rhythm, sleep-wake cycle and does not initiate ...

and Leo Cluster of galaxies. The Coma Cluster ( Abell 1656) is 230 to 300 million light-years away. It is one of the largest-known clusters, with at least 10,000 galaxies (mainly elliptical, with a few spiral galaxies). Due to its distance from Earth, most of the galaxies are visible only through large telescopes. Its brightest members are NGC 4874 and NGC 4889, both with a magnitude of 13; most others are magnitude 15 or dimmer. NGC 4889 is a giant elliptical galaxy with one of the largest-known

black hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

s (21 billion

solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es), and NGC 4921 is the cluster's brightest spiral galaxy. After observing the Coma Cluster, astronomer Fritz Zwicky first postulated the existence of

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

during the 1930s. The massive galaxy Dragonfly 44 discovered in 2015 was found to consist almost entirely of dark matter. Its mass is very similar to that of the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

, but it emits only 1% of the light emitted by the Milky Way. NGC 4676, sometimes called the Mice Galaxies, is a pair of interacting galaxies 300 million light-years from Earth. Its progenitor galaxies were spiral, and astronomers estimate that they had their closest approach about 160 million years ago. That approach triggered large regions of

star formation Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, sta ...

in both galaxies, with long "tails" of dust, stars and gas. The two progenitor galaxies are predicted to interact significantly at least one more time before they merge into a larger, probably- elliptical galaxy.

Virgo Cluster

25 years of stunning definition Messier 100

Coma Berenices contains the northern portion of the Virgo Cluster (also known as the Coma–Virgo Cluster), about 60 million light-years away. The portion includes six Messier galaxies. M85 (NGC 4382), considered elliptical or lenticular, is one of the cluster's brighter members at magnitude nine. M85 is interacting with the spiral galaxy NGC 4394 and the elliptical galaxy MCG-3-32-38. However, it is relatively isolated from the rest of the cluster. M88 (NGC 4501) is a multi-arm spiral galaxy seen at about 30° from edge-on. It has a highly-regular shape with well-developed, symmetrical arms. Among the first galaxies recognized as spiral, it has a

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 ...

in its center. M91 (NGC 4548), a

barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas ...

with a bright, diffuse nucleus, is the faintest object in Messier's catalog at magnitude 10.2. M98 (NGC 4192), a bright, elongated spiral galaxy seen nearly edge-on, appears elliptical because of its unusual angle. The magnitude-10 galaxy has no

redshift In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and e ...

. M99 (NGC 4254) is a

spiral galaxy Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''

seen face-on. Like M98 it is of magnitude-10 and has an unusually long arm on its west side. Four supernovae have been observed in the galaxy. M100 (NGC 4321), a magnitude-nine spiral galaxy seen face-on, is one of the cluster's brightest. Photographs reveal a brilliant core, two prominent spiral arms, an array of secondary arms and several dust lanes.

Other galaxies

M64 (NGC 4826) is known as the Black Eye Galaxy because of the prominent dark dust lane in front of the galaxy's bright nucleus. Also known as the Sleeping Beauty and Evil Eye galaxy, it is about 17.3 million light-years away. Recent studies indicate that the interstellar gas in the galaxy's outer regions rotates in the opposite direction from that in the inner regions, leading astronomers to believe that at least one

satellite galaxy A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and Luminosity, luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents ...

collided with it less than a billion years ago. All other evidence of the smaller galaxy has been assimilated. At the interface between the clockwise- and counterclockwise-rotating regions are many new

e and young stars. NGC 4314 is a face-on

at a distance of 40 million light-years. It is unique for its region of intense star formation, creating a ring around its nucleus which was discovered by the

. The galaxy's prodigious star formation began five million years ago, in a region with a diameter of 1,000 light-years. The core's structure is also unique because the galaxy has spiral arms which feed gas into the bar.

NGC 4414 NGC 4414, also known as the Dusty Spiral Galaxy, is an unbarred spiral galaxy about 62 million light-years away in the constellation Coma Berenices. It was discovered by Germany, German-British astronomer William Herschel on 13 March 1785. NGC ...

is an unbarred spiral flocculent galaxy about 62 million light-years away. It is one of the closest flocculent spiral galaxies. NGC 4565 is an edge-on spiral galaxy which appears superimposed on the Virgo Cluster. NGC 4565 has been nicknamed the Needle Galaxy because when seen in full, it appears as a narrow streak of light. Like many edge-on spiral galaxies, it has a prominent dust lane and a central bulge. NGC 4565 has at least two

satellite galaxies A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and Luminosity, luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents ...

, and one of them is interacting with it. NGC 4651, about the size of the

, has tidal stellar streams gravitationally stripped from a smaller, satellite galaxy. It is about 62 million light-years away. It is located on the outskirts of the cluster, and is also known as the Umbrella Galaxy. Unlike the other spiral galaxies in the cluster, NGC 4651 is rich in neutral hydrogen, which also extends beyond the optical disk. Its

is typical for a galaxy of its type. Spiral galaxy Malin 1 discovered in 1986 is the first-known giant low-surface-brightness galaxy. With UGC 1382, it is also one of the largest low-surface-brightness galaxies. In 2006 a

dwarf galaxy A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is so ...

, also named Coma Berenices, was discovered in the constellation from data obtained by 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 ...

. The galaxy is a faint satellite of the Milky Way. It is one of the faintest satellites of the

- its integrated

luminosity Luminosity is an absolute measure of radiated electromagnetic radiation, electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electroma ...

is about times that of the Sun (absolute visible magnitude of about −4.1), which is lower than many

s. A high mass to light ratio may mean that the satellite has large amounts of

. File:NGC 4789A, a subtle swarm.jpg, Dwarf irregular galaxy NGC 4789A, alt=Diffuse galaxy File:Needle Galaxy 4565.jpeg, alt=Galaxy resembling an angled needle, NGC 4565 (Needle Galaxy) File:Small ngc4651.jpg, alt=Spiral galaxy with streams of light, NGC 4651, with umbrella-shaped stellar streams File:NGC4495 - Iotw2241a.jpg, The

Coma Berenices hosts the galaxy NGC 4495 among myriad other astronomical objects. File: A jellyfish galaxy adrift (potw2321a).jpg, The jellyfish galaxy JW39 hangs serenely in this image from the NASA/ESA Hubble Space Telescope. This galaxy lies over 900 million light-years away in the constellation Coma Berenices.

Quasars

HS 1216+5032 is a bright, gravitationally lensed pair of

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

s. W Comae Berenices (or ON 231), a blazar in the constellation's northwest, was originally designated a variable star and later found to be a BL Lacertae object. As of 2009, it had the most intense

gamma ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...

spectrum of the sixty known gamma-ray blazars.

Gamma-ray bursts

Some

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant Galaxy, galaxies which represent the brightest and most powerful class of explosion in the universe. These extreme Electromagnetic radiation, ele ...

s occurred in Coma Berenices, particularly GRB 050509B on 9 May 2005 and GRB 080607 on 7 June 2008. GRB 050509B, which lasted only 0.03 second, became the first short burst with a detected afterglow.

Meteor shower

The Coma Berenicids meteor shower peaks around 18 January. Despite the shower's low intensity (averaging one or two meteors per hour) its meteors are some of the fastest, with speeds up to .

In culture

Since Callimachus' poem, Coma Berenices has been occasionally featured in culture.

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 ...

alludes to the legend in the ending of '' The Rape of the Lock'', in which the titular hair is placed among the stars. (The poem would go on to provide the names of some of the moons of Uranus.) In 1886, Spanish artist Luis Ricardo Falero created a

mezzotint Mezzotint is a monochrome printmaking process of the intaglio (printmaking), intaglio family. It was the first printing process that yielded half-tones without using line- or dot-based techniques like hatching, cross-hatching or stipple. Mezzo ...

print personifying Coma Berenices alongside Virgo and Leo. In 1892, the Russian poet Afanasy Fet made the constellation the subject of his short poem, composed for the Countess Natalya Sollogub. The Swedish poet Gunnar Ekelöf wrote the lines "Your friend the comet combed his hair with the

Leonids The Leonids ( ) are a prolific annual meteor shower associated with the comet 55P/Tempel–Tuttle, Tempel–Tuttle, and are also known for their spectacular meteor storms that occur about every 33 years. The Leonids get their name from the loca ...

/ Berenice let her hair hang down from the sky" in a 1933 poem. American writer and folksinger Richard Fariña mentions Coma Berenices in his 1966 novel '' Been Down So Long It Looks Like Up To Me'', sardonically writing about content typical to upper-level astronomy coursework at Cornell: "It's the advanced courses give you trouble. Relativity principles, spiral nebula in Coma Berenices, that kind of hassle". The Bolivian poet, Pedro Shimose, makes Coma Berenices the home address of his "Señorita NGC 4565" in his poem "Carta a una estrella que vive en otra constelación" ("Letter to a star who lives in another constellation"), included in his 1967 collection, "Sardonia". " The Irish poet W. B. Yeats, in his poem "Her Dream", refers to "Berenice's burning hair" being "nailed upon the night". Francisco Guerrero, a 20th-century Spanish composer, wrote an orchestral work on the constellation in 1996. In 1999 Irish artist Alice Maher made a series of four oversize drawings, entitled ''Coma Berenices'', of entwining black hair coils.

Notes

References

External links

The Deep Photographic Guide to the Constellations: Coma Berenices

* {{DEFAULTSORT:Coma Berenices Northern constellations Ptolemaic Kingdom in popular culture