10 Lacertae

10 Lacertae (10 Lac) is a star in the constellation Lacerta. With an apparent magnitude of 4.9, it is located around 550 parsecs (1,800 ly) distant in the small Lacerta OB1 association. It is a hot blue main-sequence star of spectral type O9V, a massive star that is currently fusing its core hydrogen. It is a suspected Beta Cephei variable star.

10 Lacertae

Location of 10 Lac (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Lacerta
Right ascension	22h 39m 15.67804s[1]
Declination	+39° 03′ 00.9724″[1]
Apparent magnitude (V)	4.880[2]
Characteristics
Spectral type	O9V[3]
U−B color index	−1.010[2]
B−V color index	−0.210[2]
Variable type	β Cep?[4]
Astrometry
Radial velocity (Rv)	−10.10[5] km/s
Proper motion (μ)	RA: −1.274 mas/yr[1] Dec.: −5.605 mas/yr[1]
Parallax (π)	2.192 ± 0.131 mas[1]
Distance	1,800±103 ly (552±32 pc)[6]
Absolute magnitude (MV)	−4.17±0.12[6]
Details[6]
Mass	21.6±0.5 M☉
Radius	7.4±0.5 R☉
Luminosity	69,200+8,440 −7,520 L☉
Surface gravity (log g)	4.04±0.05 cgs
Temperature	34,550±300 K
Rotational velocity (v sin i)	14±1 km/s
Age	3.55+0.72 −0.60[6] Myr
Other designations
10 Lac, HR 8622, BD+38°4826, HD 214680, SAO 72575, HIP 111841, NSV 25932, WDS J22393+3903
Database references
SIMBAD	data

It was one of the first O-type stars (along with S Monocerotis) to be defined as an anchor point for the MKK spectral classification; since the early twentieth century it has served as such a point. Specifically, the star is representative of O9V stars, meaning relatively cool O-type stars on the main-sequence.^[7]

It is the star with the smallest angular diameter measured by the CHARA array, at 0.11±0.02 milliarcseconds.^[8]

10 Lacertae has an 8th magnitude companion about one arc-minute away.^[9]

References

1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
2. Oja, T. (September 1993). "UBV photometry of stars whose positions are accurately known. VII". Astronomy and Astrophysics Supplement Series. 100 (3): 591–592. Bibcode:1993A&AS..100..591O. ISSN 0365-0138.
3. Sota, A.; Maíz Apellániz, J.; Walborn, N. R.; Alfaro, E. J.; Barbá, R. H.; Morrell, N. I.; Gamen, R. C.; Arias, J. I. (2011). "The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-violet at R ~ 2500". The Astrophysical Journal Supplement. 193 (3): 24. arXiv:1101.4002. Bibcode:2011ApJS..193...24S. doi:10.1088/0067-0049/193/2/24. S2CID 119248206.
4. Samus, N. N.; Durlevich, O. V. (January 2009). "VizieR On-line Data Catalog: General Catalogue of Variable Stars". VizieR On-line Data Catalog. 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. Aschenbrenner, P.; Przybilla, N.; Butler, K. (2023-03-01). "Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method". Astronomy and Astrophysics. 671: A36. arXiv:2301.09462. Bibcode:2023A&A...671A..36A. doi:10.1051/0004-6361/202244906. ISSN 0004-6361.
7. Garrison, R. F. (1994). "A Hierarchy of Standards for the MK Process". Astronomical Society of the Pacific. 60: 3. Bibcode:1994ASPC...60....3G.
8. Gordon, Kathryn D.; Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel; Ireland, Michael; Hillier, D. John (December 2018). "Angular Sizes and Effective Temperatures of O-type Stars from Optical Interferometry with the CHARA Array". The Astrophysical Journal. 869 (1): 37. arXiv:1812.05511. Bibcode:2018ApJ...869...37G. doi:10.3847/1538-4357/aaec04. ISSN 0004-637X.
9. Dommanget, J.; Nys, O. (1994). "Catalogue of the Components of Double and Multiple stars (CCDM). First edition". Communications de l'Observatoire Royal de Belgique. 115. Bibcode:1994CoORB.115.....D.