| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lacerta | 
| Right ascension | 22h 31m 17.5010s | 
| Declination | +50° 16′ 56.969″ | 
| Apparent magnitude (V) | 3.777 | 
| Characteristics | |
| Spectral type | A1 V | 
| U−B color index | 0.00 | 
| B−V color index | +0.01 | 
| R−I color index | −0.03 | 
| Astrometry | |
| Radial velocity (Rv) | −4.0 ± 2 km/s | 
| Proper motion (μ) | RA: 137.22 mas/yr Dec.: 17.15 mas/yr | 
| Parallax (π) | 31.86 ± 0.54mas | 
| Distance | 102 ± 2 ly (31.4 ± 0.5 pc) | 
| Absolute magnitude (MV) | 1.29 | 
| Details | |
| Mass | 2.194 M☉ | 
| Radius | 2.1432 R☉ | 
| Luminosity | 27.6750±0.2138 L☉ | 
| Luminosity (bolometric) | 27 L☉ | 
| Temperature | 9050±157 K | 
| Rotational velocity (v sin i) | 146 km/s | 
| Age | 400 Myr | 
| Other designations | |
| Database references | |
| SIMBAD | data | 
Alpha Lacertae (Alpha Lac, α Lacertae, α Lac) is an A-type main sequence star in the constellation of Lacerta. It is the brightest star in Lacerta and has an apparent visual magnitude of approximately 3.777.
The star has a visual companion, CCDM J22313+5017B, of spectral type A and apparent visual magnitude 11.8, approximately 36 arcseconds away. The companion is optical, a chance line-of-sight coincidence.
In Chinese, 螣蛇 (Téng Shé), meaning Flying Serpent, refers to an asterism consisting of α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, β Lacertae, 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, α Lacertae itself is known as 螣蛇一 (Téng Shé yī, English: the First Star of Flying Serpent)