12 Aurigae

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12 Aurigae
Observation data
Epoch J2000       Equinox J2000
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  mas [1]
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
12 Aur, BD+46°989, GC 6424, HD 33988, SAO 40183, PPM 47919 [8]
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. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 Paunzen, E. (2015). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy & Astrophysics. 580: A23. arXiv: 1506.04568 . Bibcode:2015A&A...580A..23P. doi:10.1051/0004-6361/201526413. S2CID   73623700.
  3. ↑ Burbidge, G. R.; Burbidge, E. Margaret (September 1953). "The Balmer Decrement in Some Be Stars". Astrophysical Journal. 118: 252. Bibcode:1953ApJ...118..252B. doi: 10.1086/145747 .
  4. 1 2 3 4 5 Anders, F.; Khalatyan, A.; Queiroz, A. B. A.; Chiappini, C.; Ardevol, J.; Casamiquela, L.; Figueras, F.; Jimenez-Arranz, O.; Jordi, C.; Monguio, M.; Romero-Gomez, M.; Altamirano, D.; Antoja, T.; Assaad, R.; Cantat-Gaudin, T.; Castro-Ginard, A.; Enke, H.; Girardi, L.; Guiglion, G.; Khan, S.; Luri, X.; Miglio, A.; Minchev, I.; Ramos, P.; Santiago, B. X.; Steinmetz, M. (2022). "VizieR Online Data Catalog: StarHorse2, Gaia EDR3 photo-astrometric distances (Anders+, 2022)". Vizier Online Data Catalog. Bibcode:2022yCat.1354....0A.
  5. 1 2 3 4 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. arXiv: 1706.02208 . Bibcode:2017MNRAS.471..770M. doi: 10.1093/mnras/stx1433 . eISSN   1365-2966. ISSN   0035-8711.
  6. 1 2 3 4 Stassun, Keivan G.; et al. (September 2018). "The TESS Input Catalog and Candidate Target List". The Astronomical Journal. 156 (3): 102. arXiv: 1706.00495 . Bibcode:2018AJ....156..102S. doi: 10.3847/1538-3881/aad050 . ISSN   0004-6256.
  7. ↑ Halbedel, Elaine M. (September 1996). "Rotational Velocity Determinations for 164 Be and B Stars". Publications of the Astronomical Society of the Pacific. 108: 833. Bibcode:1996PASP..108..833H. doi: 10.1086/133804 .
  8. 1 2 "12 Aur". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-04-04.
  9. ↑ Halbedel, Elaine M. (September 1996). "Rotational Velocity Determinations for 164 Be and B Stars". Publications of the Astronomical Society of the Pacific. 108: 833. Bibcode:1996PASP..108..833H. doi: 10.1086/133804 . S2CID   119944672.
  10. ↑ 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. Bibcode:1991Ap&SS.186..161H. doi:10.1007/BF00644632. S2CID   123509301.
  11. ↑ Wright, Candace O.; et al. (2003). "The Tycho-2 Spectral Type Catalog". The Astronomical Journal. 125 (1): 359. Bibcode:2003AJ....125..359W. doi: 10.1086/345511 . S2CID   122781581.
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