Astronomy:Pi Arietis

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Short description: Multiple star system in the constellation Aries
π Arietis
Aries constellation map.svg
Red circle.svg
Location of π Arietis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aries
Right ascension  02h 49m 17.55924s[1]
Declination +17° 27′ 51.5168″[1]
Apparent magnitude (V) 5.21[2]
Characteristics
Spectral type B6 V + A0 V + F8 V[3]
U−B color index –0.47[2]
B−V color index –0.06[2]
Astrometry
Radial velocity (Rv)+8.8[4] km/s
Proper motion (μ) RA: +2.60[1] mas/yr
Dec.: –14.10[1] mas/yr
Parallax (π)4.18 ± 0.69[1] mas
Distanceapprox. 800 ly
(approx. 240 pc)
Absolute magnitude (MV)−1.56[5]
Details
Luminosity538[5] L
Rotational velocity (v sin i)70[6] km/s
Other designations
π Ari, 42 Arietis, BD+16° 355, HD 17543, HIP 13165, HR 836, SAO 93127.[7]
Database references
SIMBADdata

Pi Arietis, Latinized from π Arietis, is the Bayer designation for a multiple star system in the northern constellation of Aries. Based upon parallax measurements made during the Hipparcos mission, this system is approximately 800 light-years (250 parsecs) distant from Earth and has an apparent visual magnitude of 5.21. This is bright enough to be faintly seen with the naked eye.

The primary member of this system is a massive, B-type main sequence star with a stellar classification of B6 V. It is a close spectroscopic binary with an orbital period of 3.854 days, an eccentricity of 0.04, and a combined visual magnitude of 5.30. At an angular separation of 3.28 arcseconds is a magnitude 8.46 A-type main sequence star with a classification of A0 Vp. Finally, a fourth member of the system is a magnitude 11.0 F-type main sequence star with a classification of F8V at an angular separation of 25.2 arcseconds from the primary.[3]

Name

This star, along with δ Ari, ε Ari, ζ Ari, and ρ3 Ari, were Al Bīrūnī's Al Buṭain (ألبطين), the dual of Al Baṭn, the Belly.[8] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Buṭain were the title for five stars : δ Ari as Botein, π Ari as Al Buṭain I, ρ3 Ari as Al Buṭain II, ε Ari as Al Buṭain III dan ζ Ari as Al Buṭain IV.[9]

In Chinese, 左更 (Zuǒ Gēng), meaning Official in Charge of the Forest, refers to an asterism consisting of π Arietis, ν Arietis, μ Arietis, ο Arietis and σ Arietis.[10] Consequently, the Chinese name for π Arietis itself is 左更五 (Zuǒ Gēng wu, English: the Fifth Star of Official in Charge of the Forest.)[11]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Crawford, D. L.; Barnes, J. V.; Golson, J. C. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal 76: 1058, doi:10.1086/111220, Bibcode1971AJ.....76.1058C. 
  3. 3.0 3.1 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  4. Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication (Washington: Carnegie Institution of Washington), Bibcode1953GCRV..C......0W. 
  5. 5.0 5.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode2002ApJ...573..359A. 
  7. "pi. Ari". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi.+Ari. 
  8. Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 83, ISBN 0-486-21079-0, https://archive.org/details/starnamestheirlo00alle/page/83, retrieved 2010-12-12. 
  9. Rhoads, Jack W. (November 15, 1971), "Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars", Jet Propulsion Laboratory, California Institute of Technology, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf. 
  10. (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.
  11. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 21 日

External links