Iota Geminorum (ι Geminorum, ι Gem) is a solitary[9] 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.[10]
| 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 | |
| Mass | 1.89[6] M☉ |
| Radius | 9.48±0.12[7] R☉ |
| Luminosity | 53.7±2.8[7] L☉ |
| Surface gravity (log g) | 2.8[4] cgs |
| Temperature | 5,072±68[7] K |
| Metallicity [Fe/H] | −0.17[4] dex |
| Rotational velocity (v sin i) | 0.0[4] km/s |
| Age | 4.16±2.54[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Nomenclature
editIn 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.[11] Consequently, ι Geminorum itself is known as 五諸侯三 (Wu Zhū Hóu sān, English: the Third Star of Five Feudal Kings.).[12] It has been called by the proper name Propus, meaning "forefoot" in Latin, but this name is now assigned to η Geminorum.[13]
Properties
editBased 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[14] 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 9.5 times the solar radius. It shines with 54 times the Sun's luminosity from its outer atmosphere at an effective temperature of 5,072 K.[7]
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.
- ^ a b c d Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Van Belle, Gerard T. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1): 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b, S2CID 119427037.
- ^ "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.
- ^ "研究資源 - 亮星中英對照表" [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.