12 Vulpeculae

12 Vulpeculae is a star in the northern constellation of Vulpecula, located approximately 630 light years away based on parallax.[1] It has the variable star designation V395 Vul; 12 Vulpeculae is the Flamsteed designation. This object is visible to the naked eye as a faint, blue-white hued star with a baseline apparent visual magnitude of 4.96.[2] It is moving closer to the Earth with a heliocentric radial velocity of -25 km/s.[5]

12 Vulpeculae
Location of 12 Vulpeculae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Vulpecula
Right ascension  19h 51m 04.10821s[1]
Declination +22° 36′ 36.1732″[1]
Apparent magnitude (V) 4.96[2] (4.78 - 4.97)[3]
Characteristics
Spectral type B2.5V[4]
U−B color index −0.69[2]
B−V color index −0.12[2]
Variable type Be star[3]
Astrometry
Radial velocity (Rv)−24.90[5] km/s
Proper motion (μ) RA: +23.02[1] mas/yr
Dec.: −15.88[1] mas/yr
Parallax (π)5.18 ± 0.25[1] mas
Distance630 ± 30 ly
(193 ± 9 pc)
Absolute magnitude (MV)−1.52[4]
Details
Mass6.8[6] M☉
Luminosity963[4] L☉
Surface gravity (log g)3.36[7] cgs
Temperature18,859[7] K
Metallicity [Fe/H]−0.01[7] dex
Rotational velocity (v sin i)195[8] km/s
Other designations
12 Vul, V395 Vul, BD+22°3833, FK5 3585, GC 27493, HD 187811, HIP 97679, HR 7565, SAO 87813[9]
Database references
SIMBADdata

This is a variable Be star with a stellar classification of B2.5V;[4] its brightness ranges from magnitude 4.78 down to 4.97.[3] As is true with other Be stars, it has a high rate of rotation with a projected rotational velocity of 195 km/s.[8] The star has 6.8[6] times the mass of the Sun and is radiating 963[4] times the Sun's luminosity from its photosphere at an effective temperature of 18,859 K.[7]

References
  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Samus, N. N.; Durlevich, O. V.; 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....1.2025S.
  4. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. Vizier catalog entry
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410: 190. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. Vizier catalog entry
  7. Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014.
  8. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573: 359. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  9. "8 Vul". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-11-19.
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