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]
A light curve for Alpha Doradus, plotted from TESS data[10] [11]
Quick Facts Apparent magnitude (V), Characteristics ...
Alpha Doradus
Location of α Doradus (circled)
Observation dataEpoch J2000.0 Equinox J2000.0 (ICRS )
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/sProper motion (μ) RA: 58.06[1] mas /yr Dec.: 12.73[1] mas /yr Parallax (π)19.34 ± 0.31 mas [6] 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)B 1986Argument 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 α Dor, Alpha Doradus, Alpha Dor ,
CD −55 916,
CPD −55 663,
FK5 171,
GC 5600,
HD 29305,
HIP 21281,
HR 1465,
SAO 233564,
PPM 333592,
CCDM J04340-5503AB,
WDS 04340-5503AB[5]
Database references SIMBAD data
Close
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]
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.
Kaler, James B., Alpha Dor , retrieved 2012-03-04
"alf Dor" . The International Variable Star Index . AAVSO. Retrieved 2 July 2022 .