Lambda Eridani

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Star
Lambda Eridani
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Eridanus
Right ascension 05 h 09 m 8.78 s
declination −08 ° 45 ′ 14.7 ″
Apparent brightness +4.27 (4.17 to 4.34) mag
Typing
B − V color index (-0.20) 
U − B color index (-0.90) 
R − I index (-0.20) 
Spectral class B2 III (e) p
Variable star type LERI + GCAS 
Astrometry
Radial velocity (2.0) km / s
parallax 4.02 ± 0.18  mas
distance (650)  ly
(200)  pc
Proper movement 
Rec. Share: (0.25)  mas / a
Dec. portion: (−1.97)  mas / a
Physical Properties
Other names
and catalog entries
Bayer name λ Eridani
Flamsteed name 69 Eridani
Bonn survey BD -08 ° 1040
Henry Draper Catalog HD 33328 [1]
Hipparcos catalog HIP 23972 [2]
SAO catalog SAO 131824 [3]
Tycho catalog TYC 5330-1723-1 [4]
2MASS catalog 2MASS J05090877-0845147 [5]
Other names FK5 190

Lambda Eridani is a spectral class B star at a distance of about 650  light years . It is the prototype of the Lambda Eridani Stars , which belong to the Eruptive Variable Stars .

Lambda Eridani rotates at a high speed of about 325 km / s. This is close to the 440 km / s speed that would tear the star apart. Due to the high speed of rotation, the star is flattened and its radius at the equator exceeds its radius at the poles by about 25%.

See also

Individual evidence

  1. ↑ a b c d e f g h Simbad
  2. ↑ a b lam Eri. In: VSX. AAVSO, accessed September 3, 2018 .
  3. ↑ JC Becker: Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra . In: The Astrophysical Journal Supplement Series . 217, No. 2, April 2015, p. 13. arxiv : 1503.03874 . 29. bibcode : 2015ApJS..217 ... 29B . doi : 10.1088 / 0067-0049 / 217/2/29 .
  4. ↑ Y. Fremat: Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars . In: Astronomy and Astrophysics . 440, No. 1, 2005, pp. 305-320. arxiv : astro-ph / 0503381 . bibcode : 2005A & A ... 440..305F . doi : 10.1051 / 0004-6361: 20042229 .
  5. ^ GT van Belle: Interferometric observations of rapidly rotating stars . In: The Astronomy and Astrophysics Review . 20, No. 1, March 2012, p. 51. arxiv : 1204.2572 . bibcode : 2012A & ARv..20 ... 51V . doi : 10.1007 / s00159-012-0051-2 .