Astronomy:12 Aurigae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 16m 27.08298s[1] |
| Declination | +46° 24′ 57.8118″[1] |
| Apparent magnitude (V) | 6.988[2] |
| Characteristics | |
| Spectral type | B2 Ve[3] |
| Astrometry | |
| Proper motion (μ) | RA: −3.321[1] mas/yr Dec.: −1.2106[1] mas/yr |
| Parallax (π) | 1.5264 ± 0.0303[1] mas |
| Distance | 2,140 ± 40 ly (660 ± 10 pc) |
| Details | |
| Mass | 3.0[4] M☉ |
| Radius | 18[5] R☉ |
| Luminosity | 635[5] L☉ |
| Surface gravity (log g) | 2.47[4] cgs |
| Temperature | 8,688[6] K |
| Metallicity | −0.94[4] |
| Rotational velocity (v sin i) | 100±41[7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
12 Aurigae is a Be star in the northern constellation Auriga. It lies below the normal limit for visibility to the naked eye, having an apparent visual magnitude of 6.988.[2] It lacks a designation from the Hipparcos catalogue. It is located just under half a degree north of Capella.[8]
Assigned spectral classes for 12 Aurigae vary greatly from B2 to B5 and the luminosity class from V (main sequence) to Ia (luminous supergiant). Its spectrum shows prominent emission lines, but the spectrum is complicated by the appearance of sharp shell components to some of the spectral lines.[9] The colour of the star as shown by the B-V and U-B colour indices is not consistent with an early B spectral class,[10] leading to many estimates of its effective temperature that are much lower than expected for a B-class star.[6][4] The expected temperature for a B5 spectral type would be 15,400 K,[11] but most sources assign a temperature of around 8,000 K.[6][4] Other properties also vary between different sources, for example the bolometric luminosity derived from the distance and temperature is 25 L☉,[6] while it is 635 L☉ when derived by fitting the spectral energy distribution.[5] A calculation of the stellar properties assuming the maximum possible interstellar extinction in the direction of 12 Aurigae results in a temperature of 14,336 K and a luminosity of 8,092 L☉, although it is strongly noted that the likely extinction is much lower.[5]
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 Paunzen, E. (2015). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy & Astrophysics 580: A23. doi:10.1051/0004-6361/201526413. Bibcode: 2015A&A...580A..23P.
- ↑ Burbidge, G. R.; Burbidge, E. Margaret (September 1953). "The Balmer Decrement in Some Be Stars". Astrophysical Journal 118: 252. doi:10.1086/145747. Bibcode: 1953ApJ...118..252B.
- ↑ 4.0 4.1 4.2 4.3 4.4 Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardevol, J.; Casamiquela, L.; Figueras, F.; Jimenez-Arranz, O. et al. (2022). "VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)". Vizier Online Data Catalog. Bibcode: 2022yCat.1354....0A.
- ↑ 5.0 5.1 5.2 5.3 McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770–791. doi:10.1093/mnras/stx1433. ISSN 0035-8711. Bibcode: 2017MNRAS.471..770M.
- ↑ 6.0 6.1 6.2 6.3 Stassun, Keivan G. et al. (September 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal 156 (3): 102. doi:10.3847/1538-3881/aad050. ISSN 0004-6256. Bibcode: 2018AJ....156..102S.
- ↑ Halbedel, Elaine M. (September 1996). "Rotational Velocity Determinations for 164 Be and B Stars". Publications of the Astronomical Society of the Pacific 108: 833. doi:10.1086/133804. Bibcode: 1996PASP..108..833H.
- ↑ 8.0 8.1 "12 Aur". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=12+Aur.
- ↑ Halbedel, Elaine M. (September 1996). "Rotational Velocity Determinations for 164 Be and B Stars". Publications of the Astronomical Society of the Pacific 108: 833. doi:10.1086/133804. Bibcode: 1996PASP..108..833H.
- ↑ Hamdy, M. A.; Elazm, M. S. A.; Saad, S. M. (1991). "Spectral reclassification of some be stars using ΔQ method". Astrophysics and Space Science 186 (1): 161. doi:10.1007/BF00644632. Bibcode: 1991Ap&SS.186..161H.
- ↑ Wright, Candace O. et al. (2003). "The Tycho-2 Spectral Type Catalog". The Astronomical Journal 125 (1): 359. doi:10.1086/345511. Bibcode: 2003AJ....125..359W.
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