10 Lacertae
Star in the constellation Lacerta
From Wikipedia, the free encyclopedia
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.
 | |
| 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±100 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 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 as of 2018[update], at 0.11±0.02 milliarcseconds.[8]
10 Lacertae has an 8th magnitude companion about one arc-minute away.[9]