Alfirk

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Star
Alfirk (β Cephei)
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Cepheus
Right ascension 21 h 28 m 39.57 s
declination + 70 ° 33 ′ 38.5 ″
Apparent brightness 3.23 (3.16 to 3.27) mag
Typing
B − V color index (−0.22) 
U − B color index (−0.96) 
R − I index (−0.22) 
Spectral class B2 IIIeV
Variable star type BCEP 
Astrometry
Radial velocity (−8 ± 2) km / s
parallax (4.76 ± 0.30)  mas
distance (680 ± 50)  ly
(210)  pc
Physical Properties
Other names
and catalog entries
Bayer name β Cephei
Flamsteed name 8 Cephei
Bonn survey BD + 69 ° 1173
Bright Star Catalog HR 8238 [1]
Henry Draper Catalog HD 205021 [2]
Hipparcos catalog HIP 106032 [3]
SAO catalog SAO 10057 [4]
Tycho catalog TYC 4465-2643-1 [5]
2MASS catalog 2MASS J21283958 + 7033389 [6]
Other names Alfirk, FK5 809

β Cephei ( Beta Cephei ) is a star in the constellation Cepheus . He bears the proper name Alfirk ( Arabic الفرق, DMG al-Firq ).

Beta Cephei is the prototype of a class of pulsation-variable stars called Beta Cephei stars . Its apparent brightness fluctuates between +3.16 m and +3.27 m with a period of 0.1904844 days .

Web links

Individual evidence

  1. ↑ a b c d e f bet Cep. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on October 31, 2018 .
  2. ↑ a b c d bet Cep. In: VSX. AAVSO, accessed October 31, 2018 .
  3. ↑ Van Leeuwen (2007)