Astronomy:Pi Virginis

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Short description: Binary star in the constellation Virgo
π Virginis
Virgo constellation map.svg
Red circle.svg
Location of π Virginis (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Virgo
Right ascension  12h 00m 52.39042s[1]
Declination +06° 36′ 51.5571″[1]
Apparent magnitude (V) 4.64[2]
Characteristics
Spectral type A5 V[3]
U−B color index +0.12[2]
B−V color index +0.12[2]
Astrometry
Radial velocity (Rv)−10.4[4] km/s
Proper motion (μ) RA: +0.26[1] mas/yr
Dec.: −30.10[1] mas/yr
Parallax (π)8.49 ± 0.39[1] mas
Distance380 ± 20 ly
(118 ± 5 pc)
Absolute magnitude (MV)−0.70[5]
Orbit[6]
Primaryπ Virginis A
Companionπ Virginis B
Period (P)282.69 days
Semi-major axis (a)3.55 mas
Eccentricity (e)0.265
Inclination (i)62.71°
Longitude of the node (Ω)149.34°
Periastron epoch (T)2448281.3906
Argument of periastron (ω)
(secondary)
312°
Semi-amplitude (K1)
(primary)
26.20[7] km/s
Details
π Vir A
Mass2.2[7] M
Radius1.5[8] R
Surface gravity (log g)3.51[9] cgs
Temperature8,000[9] K
Rotational velocity (v sin i)71[3] km/s
Other designations
BD+07°2502, FK5 1311, HD 104321, HIP 58590, HR 4589, SAO 119164[10]
Database references
SIMBADdata

Pi Virginis (π Vir, π Virginis) is a binary star in the zodiac constellation of Virgo. It is visible to the naked eye with an apparent visual magnitude of 4.64.[2] The distance to this star, based upon parallax measurements,[1] is roughly 380 light years.

This is a spectroscopic binary system with a stellar classification of A5V. They have an orbital period of 283 days with an eccentricity of 0.27.[7] The mass ratio of the two stars is about 0.47, with the primary having an estimated mass of around 2.2 times that of the Sun. The primary is a cool metallic-lined Am star.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 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  2. 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 Royer, F. et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics 463 (2): 671–682, doi:10.1051/0004-6361:20065224, Bibcode2007A&A...463..671R. 
  4. Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 (University of Toronto: International Astronomical Union) 30: pp. 57, Bibcode1967IAUS...30...57E. 
  5. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. ESA (1997). "The Hipparcos and Tycho Catalogues". VizieR On-line Data Catalog. Bibcode1997yCat.1239....0E. 
  7. 7.0 7.1 7.2 Ducati, J. R. et al. (January 2011), "The mass ratio and initial mass functions in spectroscopic binaries", Astronomy and Astrophysics 525: 9, doi:10.1051/0004-6361/200913895, A26, Bibcode2011A&A...525A..26D, http://www.lume.ufrgs.br/bitstream/10183/99264/1/000821103.pdf. 
  8. 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, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  9. 9.0 9.1 9.2 Paunzen, E. et al. (February 2013), "A photometric study of chemically peculiar stars with the STEREO satellites - II. Non-magnetic chemically peculiar stars", Monthly Notices of the Royal Astronomical Society 429 (1): 119–125, doi:10.1093/mnras/sts318, Bibcode2013MNRAS.429..119P. 
  10. "pi. Vir -- Spectroscopic binary", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=pi+vir, retrieved 2016-09-16.