Beta Centauri

Beta Centauri ( β Cen abbreviated ) is the second brightest star in the constellation Centaurus prominent in the southern sky ( 0.6 mag). He has in addition to the Bayer designation ( β = second brightest in the constellation ), the proper name Agena and Hadar. The former is Latin and means knee ( the centaur ), while the Arabic Hadar stands for floor; also the name of a landscape in Ethiopia.

The star is about 530 light -years from the solar system and was long thought to be a single blue - white supergiant, whose luminosity exceeds that of the sun at least 10,000 times. Only in 1935 was it J. G. Unmask haunch as a double star whose components (A, B) have only 1.3 " angular distance. Nevertheless, the position angle of the smaller star ( Hadar B) changes only slowly, so that the orbital period must be about 300 years. Has the brightness 4.1 like and can radiate 1500 times brighter than the sun, but is almost outshone by the brighter central star.

Three blue star

Small discrepancies in the spectral analysis eventually led to the discovery that the " central star " ( β Cen A and Hadar A) is a close, spectroscopic binary. The two suns were called A1 and A2 and are almost identical: both have 8 times the sun size and 15 times the sun's mass, spectral type B1 and 50,000 times the solar luminosity - especially in high-energy blue light. They circle in 2.6 AU distance ( half the distance Sun-Jupiter ) around each other ( according to other sources in 23 AE), but due to the huge masses in just 355 days.

So great and hot stars ( 30,000 ° C) " burn " their nuclear fuel much faster than dwarf stars ( like the sun ) and remain relatively short in the steady state (see main series ). Depending on the star's mass, they swell up after about 5 to 500 million years ago to the red giant or supergiant. The central star Hadar A1 and A2 are therefore likely to only have an age of 12 million years. While you could be orbiting in the outer space of planets, but are not Earth-like conditions conceivable.

Location at the starry sky

Beta Centauri is the elfthellste star in the firmament and, together with his somewhat brighter neighboring star Alpha Centauri ( α Cen ) - which is, however, much closer (4.3 light years ) - a pair of stars. Nearby also is the Southern Cross, so to find within a 15 ° total of five Stars 1 are size ( the entire starry sky there are 22 ).

Data of the system center β Cen A1 A2

  • Apparent magnitude: 0.66 m
  • Absolute Magnitude: -5.42 M
  • Spectral type B1 II
  • Radial velocity: -12 km / s
  • Apparent motion: 0.042 " / year
  • Position ( 2000.0 ): right ascension 14 h 3 m 49.40 s, declination -60 ° 22 ' 23.0 "
  • Position ( 1970.0 ): right ascension 14 h 1 m 41.4 s, declination -60 ° 13 ' 45 " (difference va precession )

Swell

  • Centaur ( constellation )
  • Binary star
  • Individual star of first magnitude and brighter
Astrometry Light-year Bright Star Catalogue Smithsonian Astrophysical Observatory Star Catalog Hadar, Ethiopia Solar mass Main sequence Myr Proper motion
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