Astronomy:6 Geminorum
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini |
| Right ascension | 06h 12m 19.09884s[1] |
| Declination | +22° 54′ 30.6531″[1] |
| Apparent magnitude (V) | 5.74 – 8.10[2] |
| Characteristics | |
| Spectral type | M1-2 Ia-Iab[3] |
| U−B color index | +1.93[4] |
| B−V color index | +1.63[4] |
| Variable type | LC[2] |
| Astrometry | |
| Radial velocity (Rv) | +27.16±0.42[5] km/s |
| Proper motion (μ) | RA: +0.144[1] mas/yr Dec.: −2.085[1] mas/yr |
| Parallax (π) | 0.5642 ± 0.0957[1] mas |
| Distance | approx. 5,800 ly (approx. 1,800 pc) |
| Absolute magnitude (MV) | −6.32[6] |
| Details | |
| Mass | ~20[7] M☉ |
| Radius | 821+60 −27[8] R☉ |
| Luminosity | 86,000[9] L☉ |
| Surface gravity (log g) | 0.0[6] cgs |
| Temperature | 3,789[10] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
6 Geminorum is a variable star in the zodiac constellation of Gemini, located roughly 5,800 light years away from the Sun. It has the variable star designation BU Geminorum; 6 Geminorum is the Flamsteed designation. At its brightest this reddish hued star is barely visible to the naked eye but is readily visible with binoculars, found southeast of M 35, just to the south of WY Geminorum. It is moving further from the Earth with a heliocentric radial velocity of +27 km/s.[5] The star is a member of the Gemini OB1 association.[12]
This is an evolved red supergiant with a stellar classification of M1-2 Ia-Iab.[3] It is a semiregular variable star, ranging from visual magnitude +5.7 down to +7.5 over a period of 325 days. It has been given the sub-classification of Lc, which means "Irregular variable supergiants of late spectral types having amplitudes of about 1 mag. in V.O".[13] The star has expanded to 821[8] times the Sun's radius and is radiating 86,000[9] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,789 K.[10]
A light curve for BU Geminorum, plotted from TESS data[14]
Messier 35, with 6 Gem visible right at the bottom edge of the image
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode: 2009yCat....102025S.
- ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series 71: 245. doi:10.1086/191373. Bibcode: 1989ApJS...71..245K.
- ↑ 4.0 4.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1.
- ↑ 5.0 5.1 Famaey, B. et al. (January 2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics 430 (1): 165–186. doi:10.1051/0004-6361:20041272. Bibcode: 2005A&A...430..165F.
- ↑ 6.0 6.1 Levesque, Emily M. (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal 628 (2): 973–985. doi:10.1086/430901. Bibcode: 2005ApJ...628..973L.
- ↑ "6 GEM". 2012. http://stars.astro.illinois.edu/sow/6gem.html.
- ↑ 8.0 8.1 Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University.
- ↑ 9.0 9.1 Mauron, N; Josselin, E (2011). "The mass-loss rates of red supergiants and the de Jager prescription". Astronomy and Astrophysics 526: A156. doi:10.1051/0004-6361/201013993. Bibcode: 2011A&A...526A.156M.
- ↑ 10.0 10.1 Mármol-Queraltó, E; Cardiel, N; Cenarro, A. J; Vazdekis, A; Gorgas, J; Pedraz, S; Peletier, R. F; Sánchez-Blázquez, P (2008). "A new stellar library in the region of the CO index at 2.3 μm. New index definition and empirical fitting functions". Astronomy and Astrophysics 489 (2): 885–909. doi:10.1051/0004-6361:200810044. Bibcode: 2008A&A...489..885M.
- ↑ "6 Gem". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=6+Gem.
- ↑ Laur, Jaan et al. (February 2017). "Variability survey of brightest stars in selected OB associations". Astronomy & Astrophysics 598: 27. doi:10.1051/0004-6361/201629395. A108. Bibcode: 2017A&A...598A.108L.
- ↑ "Variable Star Type Designations in VSX"]. https://www.aavso.org/vsx/index.php?view=about.vartypes.
- ↑ "ASAS All Star Catalogue". The All Sky Automated Survey. http://www.astrouw.edu.pl/asas/?page=aasc.
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