Rho Aurigae

ρ Aurigae
Location of ρ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga
Right ascension 05h 21m 48.417s[1]
Declination +41° 48′ 16.46″[1]
Apparent magnitude (V) +5.22[2]
Characteristics
Spectral type B5 V[3]
U−B color index −0.57[2]
B−V color index −0.14[2]
Astrometry
Radial velocity (Rv)+16.3±2.2[4] km/s
Proper motion (μ) RA: +15.053 mas/yr[1]
Dec.: −37.695 mas/yr[1]
Parallax (π)5.2029±0.1327 mas[1]
Distance630 ± 20 ly
(192 ± 5 pc)
Orbit[5]
Period (P)34.49321±0.00057 d
Eccentricity (e)0.104±0.019
Periastron epoch (T)47962.5±2.0 JD
Argument of periastron (ω)
(secondary)
3.4±12.0°
Semi-amplitude (K1)
(primary)
39.8±0.8 km/s
Details
ρ Aur A
Mass5–7[5] M
Radius3.2–3.4[6] R
Rotational velocity (v sin i)55[7] km/s
ρ Aur B
Mass2–4[5] M
Other designations
ρ Aurigae, 20 Aurigae, BD+41 1162, FK5 2400, GC 6556, HD 34759, HIP 25048, HR 1749, SAO 40269, PPM 48030[8]
Database references
SIMBADdata

Rho Aurigae is a binary star system in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ρ Aurigae, and abbreviated Rho Aur or ρ Aur. This system is faintly visible to the naked eye with an apparent visual magnitude of +5.22.[2] Judging by parallax measurements, this system is approximately 630 light-years (190 parsecs) distant from the Earth, give or take a 20-light-year margin of error.[1] It is drifting further away from the Sun with a radial velocity of +16 km/s.[4]

ρ Aurigae is a single-lined spectroscopic binary system; the presence of a companion object is revealed by shifts in the stellar spectrum. The pair orbit each other with a period of 34.49 days and an orbital eccentricity of 0.10.[5]

The primary component of this system is a B-type main-sequence star defined as a standard star for the stellar classification of B5 V.[3] The deduced mass of the secondary and the lack of evidence for it in the spectrum suggest it may be a B- or A-type star somewhat less luminous than the primary.[5]

Name

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In Chinese, 咸池 (Xián Chí), meaning Pool of Harmony, refers to an asterism consisting of ρ Aurigae, λ Aurigae and HD 36041.[9] Consequently, the Chinese name for ρ Aurigae itself is 咸池一 (Xián Chí yī, English: the First Star of Pool of Harmony).[10]

References

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  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d Crawford, D. L.; et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal, 76: 1058, Bibcode:1971AJ.....76.1058C, doi:10.1086/111220.
  3. ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333.
  4. ^ a b Gontcharov, G. A. (2006), "Pulkovo compilation of radial velocities for 35495 stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  5. ^ a b c d e Horn, J.; et al. (May 1994), "The orbit of the spectroscopic binary ρ Aurigae", Astronomy and Astrophysics Supplement, 105: 119–124, Bibcode:1994A&AS..105..119H.
  6. ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  7. ^ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590.
  8. ^ "rho Aur", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-08-20.
  9. ^ 陳久金 (2005), 中國星座神話 (in Chinese), 五南圖書出版股份有限公司, ISBN 978-986-7332-25-7.
  10. ^ 天文教育資訊網 [AEEA (Activities of Exhibition and Education in Astronomy)] (in Chinese), July 13, 2006, archived from the original on 2011-07-16, retrieved 2018-10-06.

Further reading

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