Phi Virginis

φ Virginis
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 14h 28m 12.13894s[1]
Declination −02° 13′ 40.6579″[1]
Apparent magnitude (V) +4.81[2]
Characteristics
Spectral type G2 IV[2]
B−V color index +0.683[3]
Astrometry
Radial velocity (Rv)−9.88±0.15[3] km/s
Proper motion (μ) RA: −139.53[1] mas/yr
Dec.: −4.04[1] mas/yr
Parallax (π)27.58 ± 1.01[1] mas
Distance118 ± 4 ly
(36 ± 1 pc)
Absolute magnitude (MV)1.68[4]
Details[3]
Mass1.80[5] M☉
Radius4 R☉
Luminosity12.6 L☉
Surface gravity (log g)3.4 cgs
Temperature5,534 K
Metallicity [Fe/H]−0.06 dex
Rotational velocity (v sin i)15.5 km/s
Age1.5[5] Gyr
Other designations
φ Vir, 105 Virginis, BD−01° 2957, FK5 533, GJ 550.2, HD 126868, HIP 70755, HR 5409, SAO 139951.[6]

Phi Virginis (φ Vir, φ Virginis) is a binary star[7] in the zodiac constellation of Virgo. It can be seen with the naked eye, having an apparent visual magnitude of +4.81.[2] There is a magnitude 9.10 companion at an angular separation of 5.160 arcseconds.[7] The distance to this system, as determined via parallax measurements,[1] is roughly 118 light years.

The primary component has a stellar classification of G2 IV,[2] indicating that it is a G-type subgiant which is evolving away from the main sequence. It is slightly variable with an amplitude of 0.m06.[8] The star has about 1.8 times the mass of the Sun,[5] 4 times the Sun's radius, and shines with 12.6 times the luminosity of the Sun.[3] It is around 1.5[5] billion years old and is spinning with a projected rotational velocity of 15.5 km/s. The effective temperature of the star's outer atmosphere is 5,534 K.[3]

The system is a source of X-ray emission with a luminosity of 2.158×1020 erg/s.[9] A second visual companion lies at an angular separation of 91.40 arcseconds along a position angle of 202°, as of 2000.[10]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Gray, R. O.; et al. (2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148, Bibcode:2001AJ....121.2148G, doi:10.1086/319956.
  3. 1 2 3 4 5 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.
  4. ↑ Schiavon, Ricardo P. (July 2007), "Population Synthesis in the Blue. IV. Accurate Model Predictions for Lick Indices and UBV Colors in Single Stellar Populations", The Astrophysical Journal Supplement Series, 171 (1): 146−205, arXiv:astro-ph/0611464Freely accessible, Bibcode:2007ApJS..171..146S, doi:10.1086/511753.
  5. 1 2 3 4 Mallik, Sushma V.; Parthasarathy, M.; Pati, A. K. (October 2003), "Lithium and rotation in F and G dwarfs and subgiants", Astronomy and Astrophysics, 409 (1): 251–261, Bibcode:2003A&A...409..251M, doi:10.1051/0004-6361:20031084.
  6. ↑ "phi Vir -- Double or multiple star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-09-18.
  7. 1 2 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:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  8. ↑ Adelman, S. J.; et al. (December 2000), "On the Variability of G0-G9 Stars", Information Bulletin on Variable Stars, 4993: 1, Bibcode:2000IBVS.4993....1A.
  9. ↑ Makarov, Valeri V. (October 2003), "The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun", The Astronomical Journal, 126 (4): 1996–2008, Bibcode:2003AJ....126.1996M, doi:10.1086/378164.
  10. ↑ Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
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