Iota Draconis b, formally named Hypatia (pronounced or ), is an

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 ...

orbiting the K-type

giant star A giant star has a substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature. They lie above the main sequence (luminosity class V in the Yerkes spectral classification) on the Hertzsp ...

Iota Draconis Iota Draconis (ι Draconis, abbreviated Iota Dra, ι Dra), also named Edasich , is a star in the northern circumpolar constellation of Draco. A visually unremarkable star of apparent magnitude 3.3, in 2002 it was discovered to have a ...

about 101.2

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 (31

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (AU), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, and ...

s, or nearly km) from Earth in the constellation

Draco DRACO (double-stranded RNA activated caspase oligomerizer) is a group of experimental antiviral drugs formerly under development at the Massachusetts Institute of Technology. In cell culture, DRACO was reported to have broad-spectrum efficacy aga ...

. The exoplanet was found by using the

radial velocity method Doppler spectroscopy (also known as the radial-velocity method, or colloquially, the wobble method) is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in th ...

, from radial-velocity measurements via observation of

Doppler shift The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. The ''Doppler effect'' is named after the physicist Christian Doppler, who described t ...

s in the

spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ...

of the planet's parent star.

Physical characteristics

Mass

Iota Draconis b is a "super-Jupiter", a planet that has mass larger than that of the gas giants

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 ...

. It has an estimated

minimum mass In astronomy, minimum mass is the lower-bound calculated mass of observed objects such as planets, stars, binary systems, nebulae, and black holes. Minimum mass is a widely cited statistic for extrasolar planets detected by the radial velocit ...

of around 11.82 . In 2021,

astrometric Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way. History ...

observations revealed the true mass of Iota Draconis b to be 16.4 .

Host star

The planet orbits a ( K-type)

named Edasich (designated

). The star has exhausted the

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

supply in its core and is currently fusing helium. The star has a mass of 1.82 and a radius of around 12 . It has a surface temperature of 4545 K and is around 800 million years old based on its evolution. Although much younger than the Sun, the higher mass of this star correlates to a faster evolution, leading to the host star having already departed from the main sequence. When on the main sequence, Edasich was probably a Class A star with surface temperature between 7,400 and 10,000K. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K. The star's

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), ...

, a measure of how bright it appears from Earth, is 3.31. Therefore, Edasich can be seen with the naked eye.

Orbit

Iota Draconis b orbits its star with nearly 55 times the Sun's luminosity (55 ) every 511 days at an average distance of 1.275 AU (compared to

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 ...

' orbital distance from the Sun, which is 1.52 AU) It has a very

eccentric Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off- center, in geometry * Eccentricity (graph theory) of a ...

orbit, with an eccentricity of 0.7124.

Discovery

Discovered in 2002 during a

radial velocity The radial velocity or line-of-sight velocity of a target with respect to an observer is the rate of change of the vector displacement between the two points. It is formulated as the vector projection of the target-observer relative velocity ...

study of K-class giant stars, its eccentric orbit aided its detection, as giant stars have pulsations which can mimic the presence of a planet.

Name

Following its discovery the planet was designated Iota Draconis b. In July 2014, 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 ...

launched

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 ...

, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced that the winning name for this planet was Hypatia. The winning name was submitted by Hypatia, a

student society A student society, student association, university society, student club, university club, or student organization is a society or an organization, operated by students at a university, college, or other educational institution, whose membership t ...

of the Physics Faculty of the

Universidad Complutense de Madrid The Complutense University of Madrid (, UCM; ) is a public research university located in Madrid. Founded in Alcalá in 1293 (before relocating to Madrid in 1836), it is one of the oldest operating universities in the world, and one of Spain's ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

Hypatia Hypatia (born 350–370 – March 415 AD) was a Neoplatonist philosopher, astronomer, and mathematician who lived in Alexandria, Egypt (Roman province), Egypt: at that time a major city of the Eastern Roman Empire. In Alexandria, Hypatia was ...

was a famous Greek astronomer, mathematician, and philosopher.

References

External links

''SolStation'': Edasich/Iota Draconis
{{DEFAULTSORT:Iota Draconis b Draco (constellation) Giant planets Exoplanets discovered in 2002 Exoplanets detected by radial velocity Exoplanets detected by astrometry Exoplanets with proper names