Kappa Geminorum (κ Geminorum, κ Gem) is a binary star system in the northern zodiac constellation of Gemini. It is visible to the naked eye with an apparent visual magnitude of 3.568.[2] Based upon an annual parallax shift of 23.07 mas,[1] the system is located about 141 light years distant from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 07h 44m 26.85357s[1] |
| Declination | 24° 23′ 52.7872″[1] |
| Apparent magnitude (V) | 3.568[2] 8.2[3] |
| Characteristics | |
| Spectral type | G9 III[4] |
| U−B color index | 0.700[2] |
| B−V color index | 0.941[2] |
| Astrometry | |
| Radial velocity (Rv) | 20.6[5] km/s |
| Proper motion (μ) | RA: −23.39[1] mas/yr Dec.: −54.57[1] mas/yr |
| Parallax (π) | 23.07 ± 0.22 mas[1] |
| Distance | 141 ± 1 ly (43.3 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.35[6] |
| Details | |
| Mass | 2.07[7] M☉ |
| Radius | 11.00±0.16[8] R☉ |
| Luminosity | 69.3±3.7[8] L☉ |
| Surface gravity (log g) | 2.8[9] cgs |
| Temperature | 5,020±68[8] K |
| Metallicity [Fe/H] | −0.16[9] dex |
| Rotational velocity (v sin i) | 3.3[9] km/s |
| Age | 2.07[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
In Chinese astronomy, Kappa Geminorum is called 積薪, Pinyin: Jīxīn, meaning Pile of Firewood, because this star is marking itself and stand alone in Pile of Firewood asterism, Well mansion (see : Chinese constellation).[11] 積薪 (Jīxīn) westernized into Tseih Tsing, but the name Tseih Tsing was designated for χ Gem and μ Cnc by R.H. Allen, with the meaning is "piled-up fuel"[12] In Japanese, 隆博星 (Takahiro-boshi), meaning "Esteemed Nobility Star," refers to the Japanese description of κ Geminorum.
This is a probable astrometric binary[3] system with the components having an angular separation of 7.2 arcseconds along a position angle of 241°, as of 2014.[13] The primary is an evolved G-type giant star with a stellar classification of G9 III.[4] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[14] It has double the mass of the Sun,[7] but has expanded to 11 times the solar radius. The star radiates around 69 times the Sun's luminosity from its outer atmosphere at an effective temperature of 5,020 K.[8] It shows a leisurely spin with a projected rotational velocity of 3.3 km/s, and is around two billion years old.[7] The secondary component is a magnitude 8.2 star.[3]
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 d 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 c Eggleton, P. P.; Tokovinin, A. A. (September 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.
- ^ a b Abt, Helmut A. (2008). "Visual Multiples. IX. MK Spectral Types". The Astrophysical Journal Supplement Series. 176 (1): 216–217. Bibcode:2008ApJS..176..216A. doi:10.1086/525529.
- ^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
- ^ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
- ^ a b c d Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
- ^ 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.
- ^ a b c 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.
- ^ "kap Gem -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-05.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日
- ^ Allen, Richard Hinckley, Star Names — Their Lore and Meaning: Gemini.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, archived from the original on 2019-06-25, retrieved 2012-02-04.
External links
edit- Kaler, James B. (November 2, 2011), "Kappa Geminorum", Stars, University of Illinois, retrieved 2016-12-06.