Beta Hydrae

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
Distance370 ± 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
Mass3.36 ± 0.15[8] M
Radius4.0 ± 0.6[8] R
Luminosity (bolometric)210[9] L
Temperature11,100[8] K
Age2.2 × 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
SIMBADdata

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

  1. 1 2 3 HIP 57936, record for component 1, Hipparcos catalogue; CDS ID I/239.
  2. 1 2 3 Entry 11529-3354, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line September 23, 2008.
  3. 1 2 3 4 5 6 7 V* alf Dor -- Variable Star, database entry, SIMBAD. Accessed on line September 3, 2008.
  4. 1 2 3 HIP 57936, record for component 2, Hipparcos catalogue; CDS ID I/239.
  5. 1 2 3 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. 1 2 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. 1 2 3 North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286Freely accessible, Bibcode:1998A&A...334..181N
  9. 1 2 3 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.
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