Astronomy:30 Geminorum
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 43m 59.28697s[1] |
| Declination | +13° 13′ 40.8188″[1] |
| Apparent magnitude (V) | 4.49[2] |
| Characteristics | |
| Spectral type | K0+ III Ca1[3] |
| B−V color index | 1.167±0.006[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.50±0.25[4] km/s |
| Proper motion (μ) | RA: −0.269[1] mas/yr Dec.: −53.503[1] mas/yr |
| Parallax (π) | 10.9027 ± 0.2048[1] mas |
| Distance | 299 ± 6 ly (92 ± 2 pc) |
| Absolute magnitude (MV) | −0.25[2] |
| Details | |
| Mass | 2.29±0.62[5] M☉ |
| Radius | 22.4+0.5 −0.8[1] R☉ |
| Luminosity | 188.9±4.1[1] L☉ |
| Surface gravity (log g) | 2.18±0.11[5] cgs |
| Temperature | 4,518+82 −47[1] K |
| Metallicity [Fe/H] | −0.11±0.05[5] dex |
| Rotational velocity (v sin i) | 2.7[4] km/s |
| Age | 1.20+0.31 −0.25[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
30 Geminorum is a suspected astrometric binary[7] star system in the northern zodiac constellation of Gemini. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.49.[2] The distance to this star, as estimated through the use of parallax, is about 299 light years.[1] It is drifting further away from the Sun with a heliocentric radial velocity of +9.5 km/s.[4]
This is an aging giant star with a stellar classification of K0+ III Ca1,[3] having exhausted the supply of hydrogen at its core and expanded to 22[1] times the Sun's radius. The suffix notation indicates it displays an overabundance of calcium in its spectrum. It is a red clump giant,[8] which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star is about 1.2[5] billion years old with 2.3[5] times the Sun's mass. It is radiating 189[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,518 K.[1]
There is a 13th magnitude visual companion located at an angular separation of 21.20″ along a position angle of 187° from the brighter star, as of 2011.[9]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Keenan, P. C.; McNeil, R. C. (1989), "The Perkins catalog of revised MK types for the cooler stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 4.2 Massarotti, Alessandro et al. (2008), "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Feuillet, Diane K. et al. (2016), "Determining Ages of APOGEE Giants with Known Distances", The Astrophysical Journal 817 (1): 40, doi:10.3847/0004-637X/817/1/40, Bibcode: 2016ApJ...817...40F.
- ↑ "30 Gem". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=30+Gem.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal 539 (2): 732–741, doi:10.1086/309278, Bibcode: 2000ApJ...539..732A.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
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