QV Andromedae

QV Andromedae (abbreviated to QV And, also known as HR 369 in the Bright Star Catalogue) is an Alpha2 Canum Venaticorum variable in the constellation Andromeda. Its maximum apparent visual magnitude is 6.6, so it can be seen by the naked eye under very favourable conditions. The brightness varies slightly following a periodic cycle of approximately 5.23 days.[3]

QV Andromedae
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 01h 16m 24.4904s[1]
Declination +48° 04′ 56.00453″[1]
Apparent magnitude (V) 6.608 (variable) [2]
Characteristics
Spectral type B9IIIpSi[3]
Apparent magnitude (U) 6.23[4]
Apparent magnitude (B) 6.559[2]
Apparent magnitude (V) 6.608[2]
Apparent magnitude (G) 6.5628[1]
Apparent magnitude (J) 6.554[5]
Apparent magnitude (H) 6.638[5]
Apparent magnitude (K) 6.657[5]
U−B color index -0.35[6]
B−V color index -0.04335[2]
Variable type ACV
Astrometry
Radial velocity (Rv)−13.6±3[7] km/s
Proper motion (μ) RA: 9.696±0.121[1] mas/yr
Dec.: 2.699±0.166[1] mas/yr
Parallax (π)4.4041 ± 0.0914[1] mas
Distance740 ± 20 ly
(227 ± 5 pc)
Details
Mass4.4[8] M☉
Luminosity266.63[9] L☉
Surface gravity (log g)3.541±0.039[8] cgs
Temperature12384±150[8] K
Rotational velocity (v sin i)49±15[8] km/s
Other designations
2MASS J01162450+4804561, BD+47 357, FK5 2085, HD 7546, HIP 5939, HR 369, SAO 37067, TYC 3268-835-1
Database references
SIMBADdata

The stellar classification of this star is B9IIIpSi,[3] where the pSi suffix indicates that the star shows peculiar chemical composition with stronger than usual silicon lines. This type of star is known as an Ap star, with the chemical peculiarities caused by strong magnetic fields and slow rotation leading to chemical stratification in the atmosphere.[6] The star is rotating at a projected rotational velocity of 49 km/s,[8] with up to 0.05 magnitude variation of brightness during one rotation cycle. This leads to the classification of the star as an Alpha2 Canum Venaticorum variable.[3]

The variability of QV Andromedae was first identified in 1975,[10] and confirmed from Hipparcos photometry.[11] It was assigned the variable star designation QV Andromedae in the 73rd namelist of variable stars in 1997.[12]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
  3. QV And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2018-10-17.
  4. "QV And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 17, 2018.
  5. Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; et al. (June 2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues (2246): II/246. Bibcode:2003yCat.2246....0C.
  6. Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics. 498 (3): 961–966. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788.
  7. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  8. Huang, W.; Gies, D. R.; McSwain, M. V. (2010). "A Stellar Rotation Census of B Stars: From ZAMS to TAMS". The Astrophysical Journal. 722 (1): 605–619. arXiv:1008.1761. Bibcode:2010ApJ...722..605H. doi:10.1088/0004-637X/722/1/605. S2CID 118532653.
  9. 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 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. S2CID 118665352.
  10. Winzer, John Ernest (1974). "The Photometric Variability of the Peculiar a Stars". Bibcode:1974PhDT........61W. Cite journal requires |journal= (help)
  11. Adelman, Saul J. (1998). "On the HIPPARCOS photometry of chemically peculiar B, A, and F stars". Astronomy and Astrophysics Supplement Series. 132: 93–97. Bibcode:1998A&AS..132...93A. doi:10.1051/aas:1998361.
  12. Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Perova, N. B. (1985). "The 67th Name-List of Variable Stars". Information Bulletin on Variable Stars. 2681: 1. Bibcode:1985IBVS.2681....1K.
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