Beta Doradus
 Location of β Doradus (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Dorado |
| Right ascension | 05h 33m 37.51729s[1] |
| Declination | −62° 29′ 23.3692″[1] |
| Apparent magnitude (V) | 3.63[2] |
| Characteristics | |
| Spectral type | F4-G4Ia-II[3] |
| U−B color index | +0.55[3] |
| B−V color index | +0.70[2] |
| R−I color index | +0.48[2] |
| Variable type | δ Cephei[4] |
| Astrometry | |
| Radial velocity (Rv) | +7.2[5] km/s |
| Proper motion (μ) | RA: +0.79[1] mas/yr Dec.: +12.74[1] mas/yr |
| Parallax (π) | 3.14 ± 0.16[6] mas |
| Distance | 1,040 ± 50 ly (320 ± 20 pc) |
| Absolute magnitude (MV) | −3.91 ± 0.11[7] |
| Details | |
| Mass | 6.5[8] M☉ |
| Radius | 67.8 ± 0.7[9] R☉ |
| Luminosity | 3,200[7] L☉ |
| Surface gravity (log g) | 1.3[10] cgs |
| Temperature | 5,445[7] K |
| Metallicity [Fe/H] | –0.13[10] dex |
| Rotational velocity (v sin i) | 0[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Doradus (Beta Dor, β Doradus, β Dor) is the second brightest star in the southern constellation of Dorado.[8] It has an apparent visual magnitude of 3.63,[2] making it visible to the naked eye from the southern hemisphere. Based upon parallax measurements with the Hubble Space Telescope, it is located at a distance of 1,040 light-years (320 parsecs) from Earth.[6]
Beta Doradus is a Cepheid variable that regularly changes magnitude from a low of 4.05 to a high of 3.45 over a period of 9.842 days.[12] The light curve of this magnitude change follows a regular saw-tooth pattern.[13] During each radial pulsation cycle, the radius of the star varies by ±3.9 times the Sun's radius around a mean of 67.8.[9] Its spectral type and luminosity class are likewise variable, from F-type to G-type and from a supergiant to a bright giant.[3]
Far ultraviolet emissions have been detected from this star with the Far Ultraviolet Spectroscopic Explorer, while X-ray emissions were detected with the XMM-Newton space telescope. The X-ray luminosity is about 1 × 1029 ergs/sec and the emission varies with the pulsation period, suggesting a connection with the pulsation process. The peak X-ray emissions are in the 0.6–0.8 keV energy range, which occurs for plasmas with temperatures of 7–10 million K.[13]
References
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05h 33m 37.5177s, −62° 29′ 23.371″
- ↑ 1.0 1.1 1.2 1.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 3.3 HR 1922, 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 9, 2008.
- ↑ bet Dor, 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 9, 2008.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 7.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 8.0 8.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 9.0 9.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 10.0 10.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ V* bet Dor -- Classical Cepheid (delta Cep type), database entry, SIMBAD. Accessed on line September 9, 2008.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 13.0 13.1 Lua error in package.lua at line 80: module 'strict' not found.
