Lambda Lyrae

Lambda Lyrae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 19h 00m 00.82534s[1]
Declination +32° 8′ 43.8418″[1]
Apparent magnitude (V) 4.937[2]
Characteristics
Spectral type K2.5III:Ba0.5[3]
U−B color index +1.609[2]
B−V color index +1.455[2]
Astrometry
Radial velocity (Rv)−17.69±0.02[4] km/s
Proper motion (μ) RA: 6.526[1] mas/yr
Dec.: 9.765[1] mas/yr
Parallax (π)2.4502 ± 0.2016 mas[1]
Distance1,300 ± 100 ly
(410 ± 30 pc)
Absolute magnitude (MV)−3.75+0.65
−0.50[5]
Details
Mass6.3±0.8[6] M☉
Radius104.74±8.84[7] R☉
Luminosity3,561±611[7] L☉
Surface gravity (log g)2.21[5] cgs
Temperature4,361±68[7] K
Metallicity [Fe/H]−0.02[5] dex
Rotational velocity (v sin i)3.2±1.0[5] km/s
Age58.4±22.6[6] Myr
Other designations
λ Lyr, 15 Lyrae, BD+31° 3424, HD 176670, HIP 93279, HR 7192, SAO 67682[8]
Database references
SIMBADdata

λ Lyrae, Latinized as Lambda Lyrae, is a suspected binary star[9] system in the northern constellation of Lyra.[8] It is an orange-hued point of light that is dimly visible to the naked eye with an apparent visual magnitude of 4.94.[2] The system is located approximately 1,300 light years distant from the Sun based on parallax, but is drifting closer with a radial velocity of −17.7 km/s.[4]

The visible component is an aging giant star with a stellar classification of K2.5III:Ba0.5[3] and an estimated age of around 58[6] million years. The suffix notation indicates this is a mild barium star[10] and hence it may have a white dwarf companion,[9] while the colon indicates there is some uncertainty about the class. Having exhausted the supply of hydrogen at its core, it has cooled and expanded off the main sequence, and now has 105[7] times the radius of the Sun. The star has six[6] times the mass of the Sun and is radiating over 4,300 times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,361 K.[7]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference mnras172_667 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference aj135_3_892 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference tetzlaff was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference van Belle 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. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference lu1991 was invoked but never defined (see the help page).