15 Vulpeculae

15 Vulpeculae is a variable star in the northern constellation of Vulpecula, located approximately 236 light years away based on parallax.[1] It has the variable star designation NT Vulpeculae; 15 Vulpeculae is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a typical apparent visual magnitude of 4.66.[2] This object is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.[6]

15 Vulpeculae
Location of 15 Vulpeculae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Vulpecula
Right ascension  20h 01m 06.04846s[1]
Declination +27° 45′ 12.8639″[1]
Apparent magnitude (V) 4.66[2] (4.62 - 4.67)[3]
Characteristics
Spectral type A4IIIm[3] or kA5hA7mA7 (IV–V)[4]
U−B color index +0.15[5]
B−V color index +0.18[5]
Variable type α2 CVn[3]
Astrometry
Radial velocity (Rv)−26.10[6] km/s
Proper motion (μ) RA: +58.17[1] mas/yr
Dec.: +3.84[1] mas/yr
Parallax (π)13.80 ± 0.20[1] mas
Distance236 ± 3 ly
(72 ± 1 pc)
Absolute magnitude (MV)0.36[2]
Details
Luminosity59.76[2] L☉
Surface gravity (log g)3.45[4] cgs
Temperature8,084[7] K
Metallicity [Fe/H]+0.02[2] dex
Rotational velocity (v sin i)15.0[8] km/s
Other designations
15 Vul, NT Vul, BD+27°3587, FK5 1523, GC 27753, HD 189849, HIP 98543, HR 7653, SAO 88071[9]
Database references
SIMBADdata

This is an Am star with a stellar classification of A4 IIIm,[3] matching an evolved A-type giant star. However, Gray & Garrison (1989) found a class of kA5hA7mA7 (IV–V),[4] which matches a blend of subgiant and main sequence luminosity classes with the K-line (kA5) of an A5 star and the hydrogen (hA7) and metal (mA7) absorption lines of an A7 star. It is an Alpha2 Canum Venaticorum-type variable with magnitude ranging from 4.62 down to 4.67 over a period of 14 days.[3] The star is radiating 60[2] times the Sun's luminosity from its photosphere at an effective temperature of 8,084 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. 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
  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. Çay, İpek H.; Teker Yelkenci, Aysegul; Adelman, Saul J. (May 2016). "Elemental Abundance Analyses with DAO Spectrograms. XXXIX. The Am Stars 2 UMa and 15 Vul". Publications of the Astronomical Society of the Pacific. 128 (963): 054201. Bibcode:2016PASP..128e4201C. doi:10.1088/1538-3873/128/963/054201.
  5. Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
  6. 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.
  7. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. Vizier catalog entry
  8. Glebocki, R.; Gnacinski, P. (2005). "VizieR Online Data Catalog: Catalog of Stellar Rotational Velocities (Glebocki+ 2005)". VizieR On-line Data Catalog: III/244. Originally Published in: 2005csss...13..571G; 2005yCat.3244....0G. 3244. Bibcode:2005yCat.3244....0G. Vizier catalog entry
  9. "15 Vul". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-03-15.
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