Astronomy:Alpha Doradus
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| Observation data {{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]] [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}} | |
|---|---|
| Constellation | Dorado |
| A | |
| Right ascension | 04h 33m 59.778s |
| Declination | −55° 02′ 41.91″[1] |
| Apparent magnitude (V) | 3.27[2] |
| B | |
| Right ascension | 04h 33m 59.782s |
| Declination | −55° 02′ 42.39″[3] |
| Apparent magnitude (V) | 4.3[2] |
| Characteristics | |
| U−B color index | −0.35[2] |
| B−V color index | −0.10[2] |
| R−I color index | −0.09[2] |
| A | |
| Spectral type | A0IIIp[2] |
| Variable type | ACV[4] |
| B | |
| Spectral type | B9IV[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | 25.6 ± 0.9[5] km/s |
| Proper motion (μ) | RA: 58.06[1] mas/yr Dec.: 12.73[1] mas/yr |
| Parallax (π) | 19.34 ± 0.31[6] mas |
| Distance | 169 ± 3 ly (51.7 ± 0.8 pc) |
| B | |
| Proper motion (μ) | RA: 42.83[3] mas/yr Dec.: 12.94[3] mas/yr |
| Orbit[7] | |
| Period (P) | 12.1 y |
| Semi-major axis (a) | 0.18″ |
| Eccentricity (e) | 0.80 |
| Inclination (i) | 31° |
| Longitude of the node (Ω) | 140° |
| Periastron epoch (T) | B1986 |
| Argument of periastron (ω) (secondary) | 193° |
| Details | |
| A | |
| Mass | 3.33 ± 0.10[8] M☉ |
| Radius | 3.5 ± 0.3[8] R☉ |
| Luminosity (bolometric) | 195[8] L☉ |
| Surface gravity (log g) | 4.02 ± 0.07[8] cgs |
| Temperature | 11,588[8] K |
| Rotation | 2.94 days[8] |
| B | |
| Mass | 2.7[9] M☉ |
| Radius | 1.9[9] R☉ |
| Luminosity (bolometric) | 70[9] L☉ |
| Temperature | 12,200[9] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Alpha Doradus, Latinized from α Doradus, is the brightest star in the southern constellation of Dorado. The distance to this system, as measured using the parallax method, is about 169 light-years (52 parsecs).[6]
This is a binary star system[9] with an overall apparent visual magnitude that varies between 3.26 and 3.30,[4] making this one of the brightest binary stars.[12] The system consists of a subgiant star of spectral type B revolving around a giant star with spectral type A in an eccentric orbit with a period of about 12 years.[2][7] The orbital separation varies from 2 astronomical units at periastron to 17.5 astronomical units at apastron. The primary, α Doradus A, is a chemically peculiar star whose atmosphere displays an abnormally high abundance of silicon, making this an Si star.[8]
Alpha Doradus has an optical companion, CCDM J04340-5503C, located 77 arcseconds away along a position angle of 94°. It has no physical relation to the other two stars.[2][13]
References
- ↑ 1.0 1.1 1.2 HIP 21281, record for component 1, Hipparcos catalogue; CDS ID I/239.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 HR 1465, 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 3, 2008.
- ↑ 3.0 3.1 3.2 HIP 21281, record for component 2, Hipparcos catalogue; CDS ID I/239.
- ↑ 4.0 4.1 alf 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 3, 2008.
- ↑ 5.0 5.1 V* alf Dor -- Variable Star, database entry, SIMBAD. Accessed on line September 3, 2008.
- ↑ 6.0 6.1 van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.
- ↑ 7.0 7.1 "Entry 04340-5503", Sixth Catalog of Orbits of Visual Binary Stars (United States Naval Observatory), http://ad.usno.navy.mil/wds/orb6/orb6orbits.txt, retrieved 2008-09-03
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics 334: 181–187, Bibcode: 1998A&A...334..181N
- ↑ 9.0 9.1 9.2 9.3 9.4 Kaler, James B., Alpha Dor, http://stars.astro.illinois.edu/sow/alphador.html, retrieved 2012-03-04
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ "alf Dor". AAVSO. https://www.aavso.org/vsx/index.php?view=detail.top&oid=13670.
- ↑ Heintz, W. D. (April 1984), "Note on the orbit of alpha Doradus", The Observatory 104: 88–89, Bibcode: 1984Obs...104...88H
- ↑ "Entry 04340-5503, discoverer code HJ3668, components AB-C", The Washington Double Star Catalog (United States Naval Observatory), http://ad.usno.navy.mil/wds/wdsnewframe1.html, retrieved 2008-09-03
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