V424 Lacertae

V424 Lacertae (V424 Lac) is a red supergiant variable star in the constellation Lacerta. It is a member of the Lacerta OB1 stellar association.

V424 Lacertae
Location of V424 Lacertae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lacerta
Right ascension 22h 56m 25.997s[1]
Declination +49° 44′ 00.716″[1]
Apparent magnitude (V) +4.94[2]
Characteristics
Spectral type K5 Ib[3]
U−B color index +1.95[2]
B−V color index +1.77[2]
Variable type Lc[4]
Astrometry
Radial velocity (Rv)−9.50[5] km/s
Proper motion (μ) RA: −0.709 ± 0.298[6] mas/yr
Dec.: −2.317 ± 0.294[6] mas/yr
Parallax (π)1.5762 ± 0.1858[6] mas
Distanceapprox. 2,100 ly
(approx. 630 pc)
Absolute magnitude (MV)−4.27[7]
Details
Mass6.8[8] M☉
Radius274+4
−3[9] R☉
Luminosity13,100 - 14,200[1] L☉
Surface gravity (log g)+0.50[8] cgs
Temperature3,790[1] K
Other designations
V424 Lac, BD+48° 3887, HR 8726, HD 216946, BD+48°3887, HIP 113288, SAO 52516
Database references
SIMBADdata

The MK spectral type of V424 Lac has been determined to be K5,[3] but it has also been classified as M0.[7] It was discovered to be slightly variable using analysis of Hipparcos photometry. The total range is less than a tenth of a magnitude.[10] Multiple short periods are detected, as well as slow variations with a period of 1,100 or 1,601 days. Although listed in the General Catalogue of Variable Stars as a slow irregular variable, it has been considered to be either a semiregular variable or long secondary period variable.[11]

There is an ultraviolet excess from V424 Lacertae, that may be due to an unseen companion, which could also explain the long secondary period. On this assumption, a sub-stellar companion in a 1,382 day 6.2 AU orbit has been suggested.[8]

References
  1. Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  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: 0. Bibcode:2002yCat.2237....0D.
  3. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  4. 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....102025S.
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  6. 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.
  7. Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
  8. Lee, B.-C.; Han, I.; Park, M.-G.; Hatzes, A. P.; Kim, K.-M. (2014). "Low-amplitude and long-period radial velocity variations in giants HD 3574, 63 Cygni, and HD 216946". Astronomy & Astrophysics. 566: A124. arXiv:1405.5955. Bibcode:2014A&A...566A.124L. doi:10.1051/0004-6361/201321863. S2CID 54177778.
  9. Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University.
  10. Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K.
  11. Messina, Sergio (2007). "Evidence for the pulsational origin of the Long Secondary Periods: The red supergiant star V424 Lac (HD 216946)". New Astronomy. 12 (7): 556–561. Bibcode:2007NewA...12..556M. doi:10.1016/j.newast.2007.04.002.
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