Delta Aurigae

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Delta Aurigae
Diagram showing star positions and boundaries of the Auriga constellation and its surroundings
Location of δ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension  05h 59m 31.63201s[1]
Declination +54° 17′ 04.7703″[1]
Apparent magnitude (V) 3.715[2]
Spectral type K0 III[3]
U−B color index +0.837[2]
B−V color index +1.017[2]
R−I color index 0.5
Radial velocity (Rv)+8.2[4] km/s
Proper motion (μ) RA: +81.81[1] mas/yr
Dec.: –132.98[1] mas/yr
Parallax (π)25.88 ± 1.61[1] mas
Distance126 ± 8 ly
(39 ± 2 pc)
Radius11[5] R
Luminosity62[5] L
Surface gravity (log g)2.7[5] cgs
Temperature4,786[5] K
Metallicity [Fe/H]–0.15[5] dex
Rotational velocity (v sin i)3.9[5] km/s
Other designations
33 Aurigae, BD+54 970, FK5 225, HD 40035, HIP 28358, HR 2077, SAO 25502.[6]
Database references

Delta Aurigae (δ Aur, δ Aurigae) is the Bayer designation for an astrometric binary[7] star in the constellation Auriga. It is visible to the naked eye with an apparent visual magnitude of 3.715.[2] Based upon its annual parallax shift of 25.88 mas,[1] it is some 126 light-years (39 parsecs) distant from the Earth, give or take an eight light-year margin of error. This star is the namesake for the Delta Aurigids, a meteor shower that occurs between October 6–15;[8] the radiant point for this shower passes several degrees to the south of the star.[9]

Delta Aurigae is a spectroscopic binary: periodic Doppler shifts in the star's spectrum indicate orbital motion; the visible component of this system is a giant star with a stellar classification of K0 III.[3] It has 11 times the radius of the Sun and shines with 62 times the Sun's luminosity; this energy is being radiated from the star's outer envelope at an effective temperature of 4,786 K.[5] This heat gives the star the orange-hued glow of a K-type star.[10] Delta Aurigae has an orbital period of 1,283.4 days (3.514 years) and an eccentricity of 0.231.[11]


In Indian astronomy, it is known by the name Prajapati /prəˈɑːpəti/, from the Sanskrit प्रजापति prajāpati "the Lord of Created Beings".[12][13]

In Chinese, 八穀 (Bā Gǔ), meaning Eight Kinds of Crops, refers to an asterism consisting of δ Aurigae, ξ Aurigae, 26 Camelopardalis, 14 Camelopardalis, 7 Camelopardalis, 9 Aurigae, 11 Camelopardalis and 31 Camelopardalis.[14] Consequently, the Chinese name for δ Aurigae itself is 八穀一 (Bā Gǔ yī, English: the First Star of Eight Kinds of Crops), refers to the rice.


  1. ^ a b c d e f 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.
  2. ^ a b c d Oja, T. (August 1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–409, Bibcode:1986A&AS...65..405O.
  3. ^ a b Eggen, O. J. (1962), "Space-velocity vectors for 3483 stars with proper motion and radial velocity", Royal Observatory Bulletin, 51, Bibcode:1962RGOB...51...79E.
  4. ^ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
  5. ^ a b c d e f g Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  6. ^ "del Aur". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-18.
  7. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  8. ^ Reynolds, Mike D. (2010), Falling Stars: A Guide to Meteors and Meteorites, Haunted Series (2nd ed.), Stackpole Books, p. 42, ISBN 0811736164
  9. ^ Lunsford, Robert (2008), Meteors and How to Observe Them, Astronomers' Observing Guides, Springer, p. 86, ISBN 0387094601
  10. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-10, retrieved 2012-01-16
  11. ^ Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213.
  12. ^ "Auriga", by Richard Hinckley Allen in Star Names: Their Lore and Meaning
  13. ^ Monier-Williams Sanskrit dictionary: pra-cchana—pra-jalpa
  14. ^ ‹See Tfd›(in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.

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