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