Beta Doradus
  | |
| 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) | 3.14 ± 0.16 mas[6] |
| Distance | 1,040 ± 50 ly (320 ± 20 pc) |
| Absolute magnitude (MV) | −3.91±0.11[7] |
| Details | |
| Mass | 7.7±0.2[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 |
| Age | 42.5±2.7[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Doradus, Latinized from β Doradus, is the second brightest star in the southern constellation of Dorado.[12] It is a Classical Cepheid variable, with an apparent magnitude that varies between 3.46 to 4.08.[2] 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]
Characteristics
[edit]
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 R☉ around a mean of 67.8 R☉.[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 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]
References
[edit]- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d bet Dor, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars Archived 2017-06-20 at the Wayback Machine, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 9, 2008.
- ^ a b c d 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.
- ^ a b Turner, D. G. (April 1980), "The reddening of Beta Doradus", Journal of the Royal Astronomical Society of Canada, 74: 64–69, Bibcode:1980JRASC..74...64T
- ^ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
- ^ a b Benedict, G. Fritz; et al. (April 2007), "Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations", Astronomical Journal, 133 (4): 1810–1827, arXiv:astro-ph/0612465, Bibcode:2007AJ....133.1810B, doi:10.1086/511980, S2CID 16384267.
- ^ a b c Turner, David G. (April 2010), "The PL calibration for Milky Way Cepheids and its implications for the distance scale", Astrophysics and Space Science, 326 (2): 219–231, arXiv:0912.4864, Bibcode:2010Ap&SS.326..219T, doi:10.1007/s10509-009-0258-5, S2CID 119264970
- ^ a b Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873
- ^ a b Taylor, Melinda M.; Booth, Andrew J. (August 1998), "The bright southern Cepheid beta Doradus: the radial velocity curve, distance and size", Monthly Notices of the Royal Astronomical Society, 298 (2): 594–600, Bibcode:1998MNRAS.298..594T, doi:10.1046/j.1365-8711.1998.01670.x
- ^ a b Romaniello, M.; et al. (September 2008), "The influence of chemical composition on the properties of Cepheid stars. II. The iron content", Astronomy and Astrophysics, 488 (2): 731–747, arXiv:0807.1196, Bibcode:2008A&A...488..731R, doi:10.1051/0004-6361:20065661, S2CID 16955805
- ^ "V* bet Dor". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 9, 2008.
- ^ Kaler, James B., "Beta Doradus", Stars, University of Illinois, retrieved 2012-01-01
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ a b Plachy, E.; et al. (2021), "TESS Observations of Cepheid Stars: First Light Results", The Astrophysical Journal Supplement Series, 253 (1): 11, arXiv:2012.09709, Bibcode:2021ApJS..253...11P, doi:10.3847/1538-4365/abd4e3, S2CID 229297708
- ^ Engle, Scott G.; et al. (May 2009), "The Secret XUV Lives of Cepheids: FUV/X-ray observations of Polaris and β Dor", Future Directions in Ultraviolet Spectroscopy: A Conference Inspired by the Accomplishments of the Far Ultraviolet Spectroscopic Explorer Mission, AIP Conference Proceedings, vol. 1135, pp. 192–197, arXiv:0902.3449, Bibcode:2009AIPC.1135..192E, doi:10.1063/1.3154048, S2CID 16635363
