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Beta Lyrae

Beta Lyrae
Lyra constellation map.svg
Location of β Lyrae in Lyra
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 18h 50m 04.79525s
Declination +33° 21′ 45.6100″
Apparent magnitude (V) 3.52(3.25 – 4.36)
Characteristics
Spectral type B7Ve + B
U−B color index −0.56
B−V color index +0.00
Variable type β Lyr
Astrometry
Radial velocity (Rv) −19.2 km/s
Proper motion (μ) RA: 1.90 mas/yr
Dec.: −3.53 mas/yr
Parallax (π) 3.39 ± 0.17mas
Distance 960 ± 50 ly
(290 ± 10 pc)
Absolute magnitude (MV) −3.91
Absolute bolometric
magnitude
 (Mbol)
–6.3 ± 0.2 / –4.7 ± 0.1
Orbit
Companion Beta Lyrae B
Period (P) 12.9414 days
Semi-major axis (a) 0.865 ± 0.048"
Eccentricity (e) 0
Inclination (i) 92.25 ± 0.82°
Longitude of the node (Ω) 254.39 ± 0.83°
Details
β Lyr A
Mass 13.16 ± 0.3 M
Radius 6.0 ± 0.2 R
Luminosity 26,300 L
Surface gravity (log g) 4.0 ± 0.1 cgs
Temperature 30,000 ± 2,000 K
β Lyr B
Mass 2.97 ± 0.2 M
Radius 15.2 ± 0.2 R
Luminosity 6,500 L
Surface gravity (log g) 2.5 ± 0.1 cgs
Temperature 13,300 K
Age 23 Myr
Other designations
Sheliak, Shelyak, Shiliak, 10 Lyrae, AAVSO 1846+33, BD+33°3223, FK5 705, HD 174638, HIP 92420, HR 7106, SAO 67451.
Database references
SIMBAD data

Beta Lyrae (β Lyrae, abbreviated Beta Lyr, β Lyr), also named Sheliak, is a binary star system approximately 960 light-years (290 parsecs) from the Sun in the constellation of Lyra.

β Lyrae (Latinised to Beta Lyrae) is the system's Bayer designation, established by Johann Bayer in his Uranometria of 1603. It also bears the Flamsteed designation 10 Lyrae.

Beta Lyrae bore the traditional name Sheliak (occasionally Shelyak or Shiliak), derived from the Arabic الشلياق šiliyāq or Al Shilyāk, one of the names of the constellation of Lyra in Islamic astronomy. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Sheliak for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.

In Chinese astronomy, Tsan Tae (漸台 (Jiāntāi), meaning Clepsydra Terrace, refers to an asterism consisting of this star, Delta2 Lyrae, Gamma Lyrae and Iota Lyrae. Consequently, Beta Lyrae itself is known as 漸台二 (Jiāntāièr, English: the Second Star of Clepsydra Terrace.)


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