Iota Geminorum
Iota Geminorum (ι Geminorum, ι Gem) 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]
| 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] |
| Characteristics | |
| Spectral type | G9 III[3] |
| U−B color index | +0.88[2] |
| B−V color index | +1.01[2] |
| Astrometry | |
| 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 mas[1] |
| Distance | 120.4 ± 0.9 ly (36.9 ± 0.3 pc) |
| Absolute magnitude (MV) | +0.859[5] |
| Details[4] | |
| 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 | |
| Database references | |
| SIMBAD | data |
Nomenclature edit
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] It has been called by the proper name Propus, meaning "forefoot" in Latin, but this name is now assigned to η Geminorum.[12]
Properties edit
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[13] 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]
References edit
- ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ 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 (3): 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- ^ 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.
- ^ 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.
- ^ 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, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788, S2CID 16602121.
- ^ a b Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
- ^ "iot Gem". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-04.
{{cite web}}: CS1 maint: postscript (link) - ^ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ O'Meara, Steve (2007), Herschel 400 Observing Guide, Cambridge University Press, p. 76, ISBN 978-0521858939.
- ^ 陳久金 (2005). 中國星座神話 [Chinese horoscope mythology] (in Chinese). 五南圖書出版股份有限公司. ISBN 978-986-7332-25-7.
- ^ [Bright Star Sino-British comparison table] (in Chinese). 香港太空館. Archived from the original on 2011-01-30. Retrieved 2018-01-08.
- ^ "Naming stars". IAU. Retrieved 2018-11-29.
- ^ 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, arXiv:1006.3857, Bibcode:2010MNRAS.408.1225P, doi:10.1111/j.1365-2966.2010.17195.x, S2CID 44228180.