Beta Lacertae
G-type giant star in the constellation Lacerta
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Beta Lacertae (Beta Lac, β Lacertae, β Lac) is the fourth-brightest star in the constellation of Lacerta. Based upon an annual parallax shift of 19.19 mas,[1] it is 170 light-years distant from Earth. At that distance, the visual magnitude is diminished by an extinction factor of 0.17 due to interstellar dust.[6]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lacerta |
| Right ascension | 22h 23m 33.624s[1] |
| Declination | +52° 13′ 44.56″[1] |
| Apparent magnitude (V) | 4.43[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | G8 III[4] |
| U−B color index | +0.77[5] |
| B−V color index | +1.02[5] |
| V−R color index | 0.6[2] |
| R−I color index | +0.57[5] |
| Astrometry | |
| Radial velocity (Rv) | −10.4 ± 0.9[2] km/s |
| Proper motion (μ) | RA: −13.25±0.13[1] mas/yr Dec.: −186.77±0.13[1] mas/yr |
| Parallax (π) | 19.19±0.16 mas[1] |
| Distance | 170 ± 1 ly (52.1 ± 0.4 pc) |
| Absolute magnitude (MV) | +0.67[6] |
| Details[6] | |
| Mass | 0.97±0.21[4] M☉ |
| Radius | 10.96±0.23[4] R☉ |
| Luminosity | 57.7±3.0[4] L☉ |
| Surface gravity (log g) | 2.43 cgs |
| Temperature | 4803±75[4] K |
| Metallicity [Fe/H] | −0.33 dex |
| Rotational velocity (v sin i) | < 17[5] km/s |
| Age | 6.76±3.59[4] Gyr |
| Other designations | |
| β Lac, Beta Lacertae, Beta Lac, 3 Lacertae, 3 Lac, BD+51 3358, FK5 844, GC 31310, HD 212496, HIP 110538, HR 8538, NLTT 53741, PPM 40598, SAO 34395[2] | |
| Database references | |
| SIMBAD | data |
This is an evolved G-type giant with an apparent visual magnitude of approximately 4.43.[2] It is a red clump[3] star and the primary component of a suspected binary system, with the pair having an angular separation of 0.2 arcsecond.[7]
Naming
In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of β Lacertae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae and ψ Andromedae. Consequently, the Chinese name for β Lacertae itself is 螣蛇十 (Téng Shé shí, English: the Tenth Star of Flying Serpent).[8]