Alpha Lacertae

α Lacertae

α Lacertae in optical light
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lacerta
Right ascension 22h 31m 17.50131s[1]
Declination +50° 16′ 56.9682″[1]
Apparent magnitude (V) 3.76[2]
Characteristics
Spectral type A1 V[3]
U−B color index 0.00[4]
B−V color index 0.031±0.003[2]
R−I color index −0.03[4]
Astrometry
Radial velocity (Rv)−4.5±0.9[5] km/s
Proper motion (μ) RA: 137.51[1] mas/yr
Dec.: 17.01[1] mas/yr
Parallax (π)31.79 ± 0.12 mas[1]
Distance102.6 ± 0.4 ly
(31.5 ± 0.1 pc)
Absolute magnitude (MV)1.27[2]
Details[6]
Mass2.194 M☉
Radius2.1432±0.0737 R☉
Luminosity27.6750±0.2138 L☉
Surface gravity (log g)4.27±0.14[7] cgs
Temperature9,050±157 K
Rotational velocity (v sin i)128[7] km/s
Age400 Myr
Other designations
α Lac, Alpha Lacertae, Alpha Lac, 7 Lac, BD+49°3875, FK5 848, GC 31471, HD 213558, HIP 111169, HR 8585, SAO 34542, ADS 16021 A, CCDM J22313+5017A, WDS J22139+3943[8]
Database references
SIMBADdata

Alpha Lacertae, Latinised from α Lacertae, is a single[9] white-hued star in the constellation of Lacerta,[8] located 103[1] light-years from the Sun. It is the brightest star in Lacerta with an apparent visual magnitude of 3.76.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −4.5 km/s.[5]

This is an ordinary A-type main-sequence star with a stellar classification of A1 V,[3] which indicates it is generating energy through hydrogen fusion at its core. It is around 400[6] million years old with a relatively high rate of spin, showing a projected rotational velocity of 128 km/s.[7] The star has 2.2 times the mass of the Sun and 2.1 times the Sun's radius. It is radiating 28 times the Sun's luminosity from its photosphere at an effective temperature of 9,050 K.[6]

Alpha Lacertae has a visual companion, CCDM J22313+5017B, of spectral type A and apparent visual magnitude 11.8, approximately 36 arcseconds away.[10] The companion is optical, a chance line-of-sight coincidence.[4]

  1. ^ a b c d e f Cite error: The named reference VanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference bsc1 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference apj771_1_40 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference david2015 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference derosa2014 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference wds was invoked but never defined (see the help page).