Iota Draconis

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Template:Short description

Iota Draconis / Edasich
Template:Location mark
Location of ι Draconis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 3.290[2]
Characteristics
Evolutionary stage Red giant branch[3]
Spectral type K2III[4]
U−B Template:Engvar +1.230[2]
B−V Template:Engvar +1.160[2]
Variable type Suspected[5]
Astrometry
Radial velocity (Rv)−10.71[6] km/s
Proper motion (μ) RA: −8.36[1] mas/yr
Dec.: +17.08[1] mas/yr
Parallax (π)32.23±0.10 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)Script error: No such module "val".[7]
Details
MassScript error: No such module "val".[3] Template:Solar mass
RadiusScript error: No such module "val".[3] Template:Solar radius
LuminosityScript error: No such module "val".[3] Template:Solar luminosity
Surface gravity (log g)2.52Script error: No such module "Su".[3] cgs
TemperatureScript error: No such module "val".[8] K
Metallicity [Fe/H]Script error: No such module "val".[3] dex
Rotation434 days[5]
Rotational velocity (v sin i)1.5[5] km/s
Age2.49Script error: No such module "Su".[3] Gyr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Edasich, Eldsich,[9] 12 Draconis, BD+59 1654, FK5 425, FK5 571, HD 137759, HIP 75458, HR 5744, SAO 29520, 2MASS J15245578+5857577[10]
Database references
SIMBADdata

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Iota Draconis (ι Draconis, abbreviated Iota Dra, ι Dra), also named Edasich Template:IPAc-en,[11][12] is a star in the northern circumpolar constellation of Draco. A visually unremarkable star of apparent magnitude 3.3,[2] in 2002 it was discovered to have a planet orbiting it[13] (designated Iota Draconis b, later named Hypatia). From parallax measurements, this star is located at a distance of about Script error: No such module "convert". from the Sun.[1]

Nomenclature

ι Draconis (Latinised to Iota Draconis) is the star's Bayer designation. On discovery the planet was designated Iota Draconis b (or Edasich b).

It bore the traditional name Edasich, derived from the Arabic Script error: No such module "lang".' of Ulugh Beg and the Dresden Globe, or Script error: No such module "lang". 'Male hyena' by Kazwini, with Eldsich being recorded in the Century Cyclopedia.[9] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[15] included a table of the first two batches of names approved by the WGSN; which included Edasich for this star.

In July 2014 the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars.[16] The process involved public nomination and voting for the new names.[17] In December 2015, the IAU announced the winning name was Hypatia for this planet.[18] The winning name was submitted by Hypatia, a student society of the Physics Faculty of the Universidad Complutense de Madrid, Spain. Hypatia was a famous Greek astronomer, mathematician, and philosopher.[19]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Left Wall of Purple Forbidden Enclosure, refers to an asterism consisting of Iota Draconis, Theta Draconis, Eta Draconis, Zeta Draconis, Upsilon Draconis, 73 Draconis, Gamma Draconis and 23 Cassiopeiae.[20] Consequently, the Chinese name for Iota Draconis itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx),[21] representing Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Left Pivot.[22] 左樞 (Zuǒshū) is westernized into Tsao Choo by R.H. Allen with the same meaning [23]

Properties

Iota Draconis is larger and more massive than the Sun, with 1.6 times the mass and nearly 12 times the radius.[3] The spectrum matches a stellar classification of K2 III,[4] indicating this is an evolved star that has exhausted the supply of hydrogen at its core and left the main sequence. It is currently on the red giant branch, fusing hydrogen in a shell around its helium core. With an expanded outer envelope, it is radiating over 50 times the luminosity of the Sun at an effective temperature of 4,504 K.[8] This temperature gives it an orange hue that is a characteristic of K-type stars.[24] It is rotating at a leisurely rate, with a period of around 434 days.[5] It is about 2.5 billion years old.[3]

In the past Iota Draconis has been suspected of variability. However, the star has been found to have a constant luminosity to within about 0.004 magnitudes. Hence, as of 2010, the variability remains unconfirmed.[5] An excess emission of infrared radiation at a wavelength of 70μm suggests the presence of a circumstellar disk of dust; what astronomers term a debris disk.[25]

Edasich is the faintest star of which a color has been reported in pre-telescopic times. It was classified as an orange-red star.[26]

Planetary system

Template:OrbitboxPlanet begin Template:OrbitboxPlanet Template:OrbitboxPlanet Template:OrbitboxPlanet disk

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The planetary companion discovered in 2002 was the first planet known to orbit a giant star.[13] The habitable zone for this star lies in the range of 6.8–13.5 Astronomical Units, placing this planet well inside.[8] The alignment of this planet's orbit may make it directly detectable via the transit method.[5] Another long-period planet or brown dwarf was discovered in 2021, and the true masses of both planets were measured via astrometry.[27]

References

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  1. ↑ a b c d e f Script error: No such module "citation/CS1".
  2. ↑ a b c d Script error: No such module "citation/CS1".
  3. ↑ a b c d e f g h i Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ a b c d e f Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ a b c Script error: No such module "citation/CS1".
  9. ↑ a b Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ a b Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ NameExoWorlds: An IAU Worldwide Contest to Name Exoplanets and their Host Stars. IAU.org. 9 July 2014
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Final Results of NameExoWorlds Public Vote Released, International Astronomical Union, 15 December 2015.
  19. ↑ Script error: No such module "citation/CS1".
  20. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  21. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  22. ↑ Template:In lang English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  23. ↑ Star Name - R.H. Allen p. 210
  24. ↑ Script error: No such module "citation/CS1".
  25. ↑ Script error: No such module "citation/CS1".
  26. ↑ Script error: No such module "Citation/CS1".
  27. ↑ Cite error: Script error: No such module "Namespace detect".Script error: No such module "Namespace detect".

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External links

Template:SkyTemplate:Stars of Draco Template:Authority control

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