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Star in the constellation Dorado
Alpha Doradus
Location of α Doradus (circled)
Observation data
Epoch
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/s
Proper 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 1986
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
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
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]
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]
^
a
b
c
HIP 21281, record for component 1 ,
Hipparcos catalogue ;
CDS ID
I/239 .
^
a
b
c
d
e
f
g
h
i
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.
^
a
b
c
HIP 21281, record for component 2 ,
Hipparcos catalogue ;
CDS ID
I/239 .
^
a
b alf 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 3, 2008.
^
a
b
V* alf Dor -- Variable Star , database entry,
SIMBAD . Accessed on line September 3, 2008.
^
a
b van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics . 474 (2): 653–664.
arXiv :
0708.1752 .
Bibcode :
2007A&A...474..653V .
doi :
10.1051/0004-6361:20078357 .
S2CID
18759600 .
^
a
b
"Entry 04340-5503" , Sixth Catalog of Orbits of Visual Binary Stars ,
United States Naval Observatory , archived from
the original on 2005-04-24, retrieved 2008-09-03
^
a
b
c
d
e
f
g North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics , 334 : 181–187,
arXiv :
astro-ph/9802286 ,
Bibcode :
1998A&A...334..181N
^
a
b
c
d
e Kaler, James B.,
Alpha Dor , retrieved 2012-03-04
^
"MAST: Barbara A. Mikulski Archive for Space Telescopes" . Space Telescope Science Institute. Retrieved 8 December 2021 .
^
"alf Dor" . The International Variable Star Index . AAVSO. Retrieved 2 July 2022 .
^ 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 , archived from
the original on 2008-04-12, retrieved 2008-09-03