Beta Hydrae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
β Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
A
Right ascension 11h 52m 54.521s
Declination −33° 54′ 29.25″[1]
Apparent magnitude (V) 4.67;[2] 4.276(combined)[3]
B
Right ascension 11h 52m 54.550s
Declination −33° 54′ 28.73″[4]
Apparent magnitude (V) 5.47[2]
Characteristics
U−B color index −0.33[5]
B−V color index −0.10[5]
R−I color index −0.08[5]
A
Spectral type B9IIIsp...[3]
Variable type ACV[6]
Astrometry
A
Radial velocity (Rv) −1 ± 5[3] km/s
Proper motion (μ) RA: −58.02 [1] mas/yr
Dec.: 2.40[1] mas/yr
Parallax (π) 8.93 ± 0.88[3] mas
Distance 370 ± 40 ly
(110 ± 10 pc)
Absolute magnitude (MV) −1.0[7]
B
Proper motion (μ) RA: −52.70[4] mas/yr
Dec.: −8.94[4] mas/yr
Details
A
Mass 3.36 ± 0.15[8] M
Radius 4.0 ± 0.6[8] R
Luminosity (bolometric) 210[9] L
Temperature 11,100[8] K
Age 2.2 × 108 [9] years
B
Mass ~3[9] M
Other designations
β Hya, Beta Hydrae, Beta Hya, HJ 4478AB, CCDM J11529-3354AB, CD−33 8018, CPD−33 3159, GC 16258, HD 103192, HIP 57936, HR 4552, IDS 11479-3321 AB, PPM 289465, SAO 202901, WDS 11529-3354AB.[2][3]
Database references
SIMBAD data

Beta Hydrae (Beta Hya, β Hydrae, β Hya) is a double star in the constellation of Hydra.[3] Its overall apparent visual magnitude varies by 0.04 magnitudes with a period of 2.344 days, and is approximately 4.27 at maximum brightness.[10] The brighter star in the double is a giant Bp star which has been classified as an α2 Canum Venaticorum variable.[3][6]

Beta Hydrae was a latter designation of 28 Crateris.[11]

References[edit]

  1. ^ a b c HIP 57936, record for component 1, Hipparcos catalogue; CDS ID I/239.
  2. ^ a b c Entry 11529-3354, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line September 23, 2008.
  3. ^ a b c d e f g V* alf Dor -- Variable Star, database entry, SIMBAD. Accessed on line September 3, 2008.
  4. ^ a b c HIP 57936, record for component 2, Hipparcos catalogue; CDS ID I/239.
  5. ^ a b c HR 4552, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 23, 2008.
  6. ^ a b Notes, Entry 11529-3354, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line September 23, 2008.
  7. ^ From apparent magnitude and parallax.
  8. ^ a b c North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286free to read, Bibcode:1998A&A...334..181N 
  9. ^ a b c Beta Hydrae, Stars, Jim Kaler. Accessed on line September 23, 2008.
  10. ^ bet Hya, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 23, 2008.
  11. ^ Wagman, M. (August 1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy, Vol.18, NO. 3/AUG, P.209, 1987. 18: 216. Bibcode:1987JHA....18..209W.