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Beta Persei A/B/C
The reid dot shaws the location o Algol in Perseus.
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Richt ascension 03h 08m 10.1315s[1]
Declination +40° 57′ 20.332″[1]
Apparent magnitude (V) 2.12[1]
Spectral type B8V (A)[1] /K0IV (B)[2] /A5V (C)
U−B colour index −0.37
B−V colour index −0.05
Variable teep Eclipsin binary
Radial velocity (Rv)3.7 km/s
Proper motion (μ) RA: 2.39 mas/yr
Dec.: −1.44 mas/yr
Parallax (π)35.14 ± 0.90 mas
Distance93 ± 2 ly
(28.5 ± 0.7 pc)
Absolute magnitude (MV)−0.15
Mass3.59/0.79/1.67 M
Radius4.13[3]/3.0/0.9 R
Luminosity98/3.4/4.1 L
Temperatur9,200[3]/4,500/8,500 K
MetallicityNae available
Rotation65 km/s
Age< 3×108 years
Ither designations
Algol, Gorgona, Gorgonea Prima, Demon Starn, El Ghoul, β Persei, β Per, Beta Per, 26 Persei, BD+40°673, FK5 111, GC 3733, HD 19356, HIP 14576, HR 936, PPM 46127, SAO 45864.

Algol (Beta Per, β Persei, β Per), kent colloquially as the Demon Starn, is a bricht starn in the constellation Perseus. It is ane o the best kent eclipsin binaries, the first such starn tae be discovered, an an aa ane o the first (non-nova) variable starns tae be discovered. Algol is actually a three-starn seestem (Beta Persei A, B, an C) in which the lairge an bricht primary Beta Persei A is regularly eclipsed bi the dimmer Beta Persei B. Thus, Algol's magnitude is usually near-constant at 2.1, but regularly dips tae 3.4 every twa days, 20 oors an 49 minutes durin the roughly 10-oor lang partial eclipses. Thare is an aa a seicontary eclipse (the "seicont minimum") when the brichter starn occults the fainter seicontary. This seicontary eclipse can anly be detectit photoelectrically.[4] Algol gies its name tae its class o eclipsin variable, kent as Algol variables.

References[eedit | eedit soorce]

  1. a b c d Database entry for Algol A, SIMBAD. Accessed online February 9, 2008.
  2. Database entry for Algol B, SIMBAD. Accessed online February 9, 2008.
  3. a b Rhee, Joseph H.; et al. (2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912 Unknown parameter |month= ignored (help)
  4. Beta Persei, American Association of Variable Star Observers.