AR Lacertae
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lacerta |
| AR Lacertae | |
| Right ascension | 22h 08m 40.81821s |
| Declination | +45° 44′ 32.1079″ |
| Apparent magnitude (V) | 6.080 Min1 6.770 Min2 6.430 |
| WDJ220838.73+454434.04 | |
| Right ascension | 22h 08m 38.73351s |
| Declination | +45° 44′ 34.0416″ |
| Characteristics | |
| Evolutionary stage | Subgiants |
| Spectral type | K0IVe + G2IV + DA(?) |
| B−V color index | 0.567±0.008 |
| Variable type | Algol/RS CVn |
| Astrometry | |
| Radial velocity (Rv) | −33.84±0.26 km/s |
| Proper motion (μ) | RA: −52.310±0.021 mas/yr Dec.: +46.931±0.020 mas/yr |
| Parallax (π) | 23.5246±0.0228 mas |
| Distance | 138.6 ± 0.1 ly (42.51 ± 0.04 pc) |
| Absolute bolometric magnitude (Mbol) | 2.75±0.066 |
| WDJ220838.73+454434.04 | |
| Proper motion (μ) | RA: −52.851±0.062 mas/yr Dec.: +55.138±0.047 mas/yr |
| Parallax (π) | 23.5967±0.0529 mas |
| Distance | 138.2 ± 0.3 ly (42.38 ± 0.10 pc) |
| Orbit | |
| Period (P) | 1.98395±0.00002 d |
| Semi-major axis (a) | 8.869±0.015 R☉ |
| Eccentricity (e) | 0.00 (adopted) |
| Inclination (i) | 90° (adopted)° |
| Longitude of the node (Ω) | 6.9207±0.0128° |
| Periastron epoch (T) | 2451745.5794 ± 0.0002 HJD |
| Details | |
| Cooler (K0) component | |
| Mass | 1.21±0.077 M☉ |
| Radius | 2.61±0.009 R☉ |
| Luminosity (bolometric) | 3.55 L☉ |
| Surface gravity (log g) | 3.69±0.035 cgs |
| Temperature | 5,100 K |
| Rotational velocity (v sin i) | 73 km/s |
| Hotter (G5) component | |
| Mass | 1.17±0.035 M☉ |
| Radius | 1.51±0.005 R☉ |
| Luminosity (bolometric) | 2.09 L☉ |
| Temperature | 5,826 K |
| Rotational velocity (v sin i) | 46 km/s |
| WDJ220838.73+454434.04 | |
| Mass | 0.6+0.04 −0.09 M☉ |
| Radius | 0.0125+0.0014 −0.0012 R☉ |
| Age | 5.75+4.97 −2.38 Gyr |
| Other designations | |
| AR Lac, BD+45°3813, GC 30985, HD 210334, HIP 109303, HR 8448, SAO 51684, WDS J22087+4545AB | |
| Database references | |
| SIMBAD | Main system |
| WDJ220838.73+454434.04 | |
AR Lacertae is a frequently-studied triple star system in the northern constellation of Lacerta, abbreviated AR Lac. This variable star system is the prototype for "detached systems of the AR Lacertae type". It is dimly visible to the naked eye with a combined peak apparent visual magnitude of 6.08. Based on parallax measurements, AR Lac is located at a distance of 138.6 light years from the Sun. It is drifting closer with a heliocentric radial velocity of −34 km/s.