Observation data Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation
Dorado
Right ascension
05h 44m 46.37811s[1]
Declination
−65° 44′ 07.9011″[1]
Apparent magnitude (V)
+4.34[2]
Characteristics
Spectral type
A7 V[3]
U−B color index
+0.11[2]
B−V color index
+0.22[2]
Astrometry
Radial velocity (Rv)
−8.3±0.8[4] km/s
Proper motion (μ)
RA: −28.91[1] mas/yr Dec.: +5.17[1] mas/yr
Parallax (π)
21.80 ± 0.14 mas[1]
Distance
149.6 ± 1.0 ly (45.9 ± 0.3 pc)
Absolute magnitude (MV)
+1.03[5]
Details
Mass
1.85[6]M☉
Radius
2.1[7]R☉
Luminosity
29[8]L☉
Surface gravity (log g)
3.89[6] cgs
Temperature
7,828±266[6] K
Metallicity [Fe/H]
−0.40[9] dex
Rotational velocity (v sin i)
172[3] km/s
Age
940[6] Myr
Other designations
δ Dor, CPD−65° 496, FK5 1154, HD 39014, HIP 27100, HR 2015, SAO 249346[10]
Database references
SIMBAD
data
δ Doradus (often Latinised to Delta Doradus, abbreviated to δ Dor or delta Dor) is a star in the southern constellation of Dorado. Based upon an annual parallax shift of 21.80 mas as seen from Earth, it is located around 150 light years from the Sun. The star is visible to the naked eye with an apparent visual magnitude of +4.34.[2]
This is an A-type main sequence star with a stellar classification of A7 V.[3] The star is spinning rapidly with a projected rotational velocity of 172 km/s.[3] This is giving the star an oblate shape with an equatorial bulge that is 12% larger than the polar radius.[11] Although A-type stars are not expected to harbor a magnetic dynamo needed to power X-ray emission, an X-ray flux of 3.6×1027 erg/s has been detected at these coordinates. This may indicate that the star has an unseen companion.[12] δ Doradus displays an infrared excess suggesting it may be a Vega-like star with an orbiting debris disk.[9]
Currently this star is the Moon's south pole star, which occurs once every 18.6 years.[13] The pole star status changes periodically, because of the precession of the Moon's rotational axis. When δ Doradus is the pole star, it is better aligned than Earth's Polaris (α Ursae Minoris), but much fainter. It is also the south pole star of Jupiter.[citation needed]
^ abcdeCite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
^ abcdCite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
^ abcdCite error: The named reference Royer2007 was invoked but never defined (see the help page).
^Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
^Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
^ abcdCite error: The named reference David2015 was invoked but never defined (see the help page).
^Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
^Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
^ abCite error: The named reference Saffe2008 was invoked but never defined (see the help page).
^Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
^Cite error: The named reference vanBelle2012 was invoked but never defined (see the help page).
^Cite error: The named reference Schroeder2007 was invoked but never defined (see the help page).
^Patrick Moore (1983), The Guinness Book of Astronomy Facts & Feats, p. 29, In 1968 the north pole star of the Moon was Omega Draconis; by 1977 it was 36 Draconis. The south pole star is Delta Doradus.
δ Doradus (often Latinised to DeltaDoradus, abbreviated to δ Dor or delta Dor) is a star in the southern constellation of Dorado. Based upon an annual...
Zeta Draconis, while its south pole is about two degrees north of DeltaDoradus. Delta Octantis is the south pole star of Saturn. Its north pole is in the...
Omega Draconis; by 1977 it was 36 Draconis. The south pole star is DeltaDoradus. "Re: Can precession occur in the opposite direction?". Retrieved 2021-10-20...
from Zeta Draconis, while its south pole is about two degrees north of DeltaDoradus. Aside from the Sun, the most prominent objects in Jupiter's sky are...
and was outside of the Delta Scuti instability strip, and there was no evidence for any eclipsing material, although Gamma Doradus and HD 96008 were noted...
Kappa Doradus, Latinized from κ Doradus, is a solitary star located in the southern constellation Dorado. It is faintly visible to the naked eye as a...
Gamma Doradus variable. Observation of the star during the CoRoT mission showed ten pulsation frequencies, four of which are typical for Gamma Doradus variables...
Cepheids include: Eta Aquilae, Zeta Geminorum, Beta Doradus, RT Aurigae, Polaris, as well as Delta Cephei. Type II Cepheids include: W Virginis, Kappa...
as metal-poor relatives of Delta Scuti variables. Gamma Doradus variables occur in similar stars to the red end of the Delta Scuti variables, usually of...
Omega Draconis; by 1977 it was 36 Draconis. The south pole star is DeltaDoradus. 2004. Starry Night Pro, Version 5.8.4. Imaginova. ISBN 978-0-07-333666-4...
B-type star, one rotating ellipsoidal variable, seven Delta Scuti variables, six Gamma Doradus variables, and one hybrid δ Sct/γ Dor pulsator. Four spectroscopic...
the yellow G-type Delta Sculptoris C, which has an apparent magnitude of +9.4. This system is a candidate member of the AB Doradus moving group, an association...
Poretti, E. (June 2005), "Projected rotational velocities of some Delta Scuti and Gamma Doradus stars", Communications in Asteroseismology, 146: 37–39, Bibcode:2005CoAst...
tropics (near the ecliptic and thus zodiac) and in the far south Beta Doradus. The closest class member is the North Star (Polaris) whose distance is...
apparent magnitude of 5.5, but is slightly variable and is classified as a Delta Scuti variable. σ Octantis (Latinised to Sigma Octantis) is the star's Bayer...
at the edge of the instability strip near the main sequence are Gamma Doradus variables. The band of White dwarfs has three separate regions and types...
nearby stellar associations and moving groups β Pictoris moving group AB Doradus moving group King, Jeremy R.; et al. (April 2003), "Stellar Kinematic Groups...
F2 star. V529 Andromedae was the first star known to combine Gamma Doradus and Delta Scuti type pulsations. Nine different pulsation frequencies have been...
1997 when a group of astronomers measured R Doradus with a diameter of 57.0±0.5 mas, although R Doradus, being much closer to Earth at about 200 ly,...
be around 4 million L☉. A year later, it was classified as a possible S Doradus variable. A 1998 paper considers it an active LBV, an Alpha Cygni variable...
of 126 pc and photometric distance of 132 pc based on stars in the AB Doradus, Tucana-Horologium and Beta Pictoris moving groups, which are all similar...
candidate slowly pulsating B stars, one being a Delta (δ) Scuti variable, and three candidate Gamma Doradus (γ Dor) variables. There may also be three Be...
Sun. Based on the estimated age and motion, it may be a member of the AB Doradus moving group that share a common motion through space. This group has an...
Triple star system 3.28 3.26 Alpha Doradus Binary star system 3.28 Delta Aquarii Star 3.28 Pi Hydrae Star 3.28 Delta Andromedae Binary star system 3.29...
The higher frequency modes are Delta Scuti-type pulsations, while the intermediate frequencies are of the Gamma Doradus type. Lower frequency pulsations...
arctan ( d 2 D ) , {\displaystyle \delta =2\arctan \left({\frac {d}{2D}}\right),} in which δ {\displaystyle \delta } is the angular diameter in degrees...
in the constellation of Cygnus is the prototype of this class. Gamma Doradus (γ Dor) variables are non-radially pulsating main-sequence stars of spectral...
Epsilon Ophiuchi, a G-type red giant. Arcturus (α Boötis), a K-type giant. R Doradus, a K-type giant. Mira (ο Ceti), an M-type giant and prototype Mira variable...
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