Iota Geminorum

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ι Geminorum
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Gemini
Right ascension 07h 25m 43.59532s[1]
Declination +27° 47′ 53.0929″[1]
Apparent magnitude (V) 3.791[2]
Spectral type G9 III[3]
U−B color index +0.88[2]
B−V color index +1.01[2]
Radial velocity (Rv) 7.26±0.16[4] km/s
Proper motion (μ) RA: −122.66[1] mas/yr
Dec.: −84.03[1] mas/yr
Parallax (π) 27.10 ± 0.20[1] mas
Distance 120.4 ± 0.9 ly
(36.9 ± 0.3 pc)
Absolute magnitude (MV) +0.859[5]
Mass 1.89[6] M
Radius 10 R
Luminosity 48 L
Surface gravity (log g) 2.8 cgs
Temperature 4,753 K
Metallicity [Fe/H] −0.17 dex
Rotational velocity (v sin i) 0.0 km/s
Age 4.16±2.54[5] Gyr
Other designations
ι Ori, 60 Geminorum, BD+28° 1385, FK5 282, HD 58207, HIP 36046, HR 2821, SAO 79374.[7]
Database references

Iota Geminorum (ι Gem, ι Geminorum) is a solitary[8] fourth-magnitude star in the constellation Gemini. In the sky, it forms an isosceles triangle with Castor and Pollux, and is located less than a degree from the 5th magnitude stars 64 and 65 Geminorum.[9] It is called by the proper name Propus, meaning "forefoot" in Latin.

In Chinese, 五諸侯 (Wu Zhū Hóu), meaning Five Feudal Kings, refers to an asterism consisting of ι Geminorum, θ Geminorum, τ Geminorum, υ Geminorum and φ Geminorum.[10] Consequently, ι Geminorum itself is known as 五諸侯三 (Wu Zhū Hóu sān, English: the Third Star of Five Feudal Kings.).[11]


Based upon an annual parallax shift of 27.10 mass,[1] Iota Geminorum lies some 120.4 light years from the Sun. This is an evolved red clump[12] giant star with a stellar classification of G9 III.[3] It is most likely a member of the galactic thin disk population.[5] The star has 1.89[6] times the mass of the Sun, but has expanded to 10 times the solar radius. It shines with 48[4] times the Sun's luminosity from its outer atmosphere at an effective temperature of 4,753 K.[4]


In certain tribes along the shores of the Arabian sea that speak languages influenced heavily by Mesopotamia, Iota Geminorum appears in oral traditions as Saritcha. It symbolizes companionship, clearly influenced by either Greek or Babylonian mythology. In one of the Lurs epic, the princess promises her beloved eternal love and companionship under Saritcha's watchful and approving gaze.[citation needed]

See also[edit]

Iota Geminorum in fiction


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752Freely accessible, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667. 
  3. ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333. 
  4. ^ a b c d Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209. 
  5. ^ a b c Soubiran, C.; et al. (March 2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics, 480 (1): 91–101, Bibcode:2008A&A...480...91S, arXiv:0712.1370Freely accessible, doi:10.1051/0004-6361:20078788. 
  6. ^ a b Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, Bibcode:2015AJ....150...88L, arXiv:1507.01466Freely accessible, doi:10.1088/0004-6256/150/3/88, 88. 
  7. ^ "iot Gem -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-04. 
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x. 
  9. ^ O'Meara, Steve (2007), Herschel 400 Observing Guide, Cambridge University Press, p. 76, ISBN 0521858933. 
  10. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  11. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine., Hong Kong Space Museum. Accessed on line November 23, 2010.
  12. ^ Puzeras, E.; et al. (October 2010), "High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements", Monthly Notices of the Royal Astronomical Society, 408 (2): 1225–1232, Bibcode:2010MNRAS.408.1225P, arXiv:1006.3857Freely accessible, doi:10.1111/j.1365-2966.2010.17195.x.