V424 Lacertae

V424 Lacertae
	Location of V424 Lacertae (circled)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Lacerta
Right ascension	22h 56m 25.997s
Declination	+49° 44′ 00.716″
Apparent magnitude (V)	+4.94
Characteristics
Spectral type	K5 Ib
U−B color index	+1.95
B−V color index	+1.77
Variable type	Lc
Astrometry
Radial velocity (Rv)	−9.50 km/s
Proper motion (μ)	RA: −0.709 ± 0.298 mas/yr ; Dec.: −2.317 ± 0.294 mas/yr
Parallax (π)	1.5762 ± 0.1858 mas
Distance	approx. 2,100 ly ; (approx. 630 pc)
Absolute magnitude (MV)	−4.27
Details
Mass	6.8 M☉
Radius	274+4; −3 R☉
Luminosity	13,100 - 14,200 L☉
Surface gravity (log g)	+0.50 cgs
Temperature	3,790 K
Other designations
	V424 Lac, BD+48° 3887, HR 8726, HD 216946, BD+48°3887, HIP 113288, SAO 52516
Database references
SIMBAD	data

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

An ultraviolet band light curve light curve for V424 Lacertae, adapted from Messina (2007)^[10]

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.^[11] 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.^[10]

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

^ ^a ^b ^c ^d 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.
^ ^a ^b ^c 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.
^ ^a ^b 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. S2CID 123149047.
^ 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.
^ 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.
^ ^a ^b ^c 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.
^ ^a ^b 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.
^ ^a ^b ^c 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.
^ Norris, Ryan P. (2019). Seeing Stars Like Never Before: A Long-term Interferometric Imaging Survey of Red Supergiants (PDF) (PhD). Georgia State University.
^ ^a ^b 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.
^ 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.