| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 08h 03m 31.08225s |
| Declination | +27° 47′ 39.6243″ |
| Apparent magnitude (V) | 4.98 |
| Characteristics | |
| Spectral type | K2 III |
| U−B color index | +1.09 |
| B−V color index | +1.14 |
| Astrometry | |
| Radial velocity (Rv) | −3.83±0.17 km/s |
| Proper motion (μ) | RA: −25.52 mas/yr Dec.: -31.89 mas/yr |
| Parallax (π) | 12.73 ± 0.90 mas |
| Distance | 260 ± 20 ly (79 ± 6 pc) |
| Absolute magnitude (MV) | 0.461 |
| Orbit | |
| Period (P) | 2,437.8d |
| Eccentricity (e) | 0.06 |
| Periastron epoch (T) | 2442894.5 ± 10.0 JD |
| Argument of periastron (ω) (secondary) | 264° |
| Semi-amplitude (K1) (primary) | 5.2 km/s |
| Details | |
| Mass | 1.83 M☉ |
| Radius | 14 R☉ |
| Luminosity | 79 L☉ |
| Surface gravity (log g) | 2.5 cgs |
| Temperature | 4,560±5 K |
| Metallicity [Fe/H] | 0.03 dex |
| Rotational velocity (v sin i) | 3.8 km/s |
| Age | 1.92 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Chi Geminorum (χ Gem) is a binary star system in the constellation Gemini, near the eastern border with Cancer. It can be viewed with the naked eye on a dark night, having an apparent visual magnitude of 4.98. Based upon an annual parallax shift of 12.73 mas, it is located roughly 260 light years from the Sun.
The two components of this system form a spectroscopic binary with an orbital period of 2,437.8 days and an eccentricity of 0.06. The primary component is a K-type giant star with a stellar classification of K2 III. This is a candidate mild Barium star with the slight overabundance most likely acquired through accretion from what is now a white dwarf companion. The primary has an estimated 1.83 times the mass of the Sun and has expanded to 14 times the Sun's radius. The effective temperature of the outer atmosphere is 4,560 K, from whence it radiates 79 times the solar luminosity. It has a leisurely projected rotational velocity of 3.8 km/s and is around two billion years old.
References
- ^ 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- ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ a b c d e f 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 e 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.
- ^ 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 Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- ^ "* chi Gem". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-09.
{{cite web}}: CS1 maint: postscript (link) - ^ Yang, Guo-Chao; et al. (January 2016), "Chemical abundance analysis of 19 barium stars", Research in Astronomy and Astrophysics, 16 (1): 019, arXiv:1602.08704, Bibcode:2016RAA....16...19Y, doi:10.1088/1674-4527/16/1/019, S2CID 14474857, 19.