Theta Lyrae

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Theta Lyrae / BD+37° 3399 / BD+37° 3398B[1][2][3]
Observation data
Epoch J2000.0
Constellation
(pronunciation)		 Lyra
Right ascension 19h 16m 22.0951s / 19h 16m 30.069s / 19h 16m 28.7s
Declination +38° 8' 1.431" / +38° 8' 35.80" / +38° 7' 1"
Apparent magnitude (V) 4.347 / 9.5 / 11.0
Characteristics
Spectral type K0II / K2III / ?
U-B color index +1.23 / ? / ?
B-V color index +1.25 / ? / ?
Astrometry
Radial velocity (Rv) -30.9 / ? / ? km/s
Proper motion (μ) RA: -0.49 / 0.0 / ? mas/yr
Dec.: 1.23 / 14.0 / ? mas/yr
Parallax (π) 4.24 ± 0.49 mas
Distance approx. 770 ly
(approx. 240 pc)
Other designations
Theta Lyrae, 21 Lyrae, HR 7314, BD+37°3398, HD 180809, SAO 68065, HIP 94713, GC 26585, IDS 19129+3757, GSC 03121-02287, BD +37°3399, BD +37°3399B

Theta Lyrae (θ Lyr) is a star in a trinary star system, in the constellation Lyra, approximately 770 light years away from Earth. Theta Lyrae is an orange bright giant star of the spectral type K0II, meaning it possesses a surface temperature of about 5,000 kelvins, and is many times bigger and brighter, yet cooler, than our Sun. [1]

It is orbited by a subsystem composed of BD+37° 3399 and BD+37° 3399B. 10th magnitude BD+37° 3399 is a giant star with a spectral type of K2III. It is therefore almost the same temperature as Theta Lyrae, but smaller and dimmer.[2] BD+37° 3399B is an 11th magnitude star of an unknown spectral type.[3]

[edit] References

  1. ^ a b Simbad Query Result. Simbad. Retrieved on October 15, 2007.
  2. ^ a b Simbad Query Result. Simbad. Retrieved on October 15, 2007.
  3. ^ a b Simbad Query Result. Simbad. Retrieved on October 15, 2007.