Beta Doradus, Latinized from β Doradus, is the second brightest star in the southern constellation of Dorado.[11] It has a variable apparent visual magnitude,[4] and is 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.[12]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Dorado |
Right ascension | 05h 33m 37.51253s[1] |
Declination | −62° 29′ 23.3231″[1] |
Apparent magnitude (V) | 3.46 to 4.08[2] |
Characteristics | |
Spectral type | F4-G4Ia-II[3] |
U−B color index | +0.55[3] |
B−V color index | +0.70[4] |
R−I color index | +0.48[4] |
Variable type | δ Cephei[2] |
Astrometry | |
Radial velocity (Rv) | +7.2[5] km/s |
Proper motion (μ) | RA: +0.800[1] mas/yr Dec.: +9.458[1] mas/yr |
Parallax (π) | 3.1119 ± 0.2845 mas[1] |
Distance | 1,050 ± 100 ly (320 ± 30 pc) |
Absolute magnitude (MV) | −3.91±0.11[6] |
Details | |
Mass | 7.7±0.2[7] M☉ |
Radius | 67.8±0.7[8] R☉ |
Luminosity | 3,200[6] L☉ |
Surface gravity (log g) | 1.3[9] cgs |
Temperature | 5,445[6] K |
Metallicity [Fe/H] | –0.13[9] dex |
Rotational velocity (v sin i) | 0[3] km/s |
Age | 42.5±2.7[7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Beta Doradus is a Cepheid variable that regularly changes magnitude from a low of 4.08 to a high of 3.46[2] over a period of 9.84318 days.[14] The light curve of this magnitude change follows a nearly regular saw-tooth pattern, with average amplitude variations period to period about 0.005 magnitude from average amplitude of 0.62 magnitude.[14] 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.[8] 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 erg/s 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.[15]