Chi Virginis

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Chi Virginis
Diagram showing star positions and boundaries of the Virgo constellation and its surroundings
Cercle rouge 100%.svg

Location of χ Virginis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo
Right ascension 12h 39m 14.76703s[1]
Declination –07° 59′ 44.0324″[1]
Apparent magnitude (V) 4.652[2]
Characteristics
Spectral type K2 III[3]
U−B color index +1.389[2]
B−V color index +1.239[2]
Astrometry
Radial velocity (Rv) –19.7[4] km/s
Proper motion (μ) RA: –77.13[1] mas/yr
Dec.: –24.73[1] mas/yr
Parallax (π) 11.11 ± 0.29[1] mas
Distance 294 ± 8 ly
(90 ± 2 pc)
Absolute magnitude (MV) −0.29 ± 0.19[5]
Details
Mass 2.17 ± 0.28[6] M
Radius 23[7] R
Luminosity 182[7] L
Surface gravity (log g) 2.5[7] cgs
Temperature 4,395[7] K
Metallicity 0.06[7]
Rotational velocity (v sin i) 3.9[7] km/s
Age 0.86 ± 0.34[5] Gyr
Other designations
26 Virginis, BD–07°3452, GC 17227, GCRV 7604, HD 110014, HIP 61740, HR 4813, PPM 195694, SAO 138892.[8]
Database references
SIMBAD data
Exoplanet Archive data
Extrasolar Planets
Encyclopaedia
data

Chi Virginis (χ Vir, χ Virginis) is a double star in the constellation Virgo. Based upon parallax measurements, it is approximately 294 light-years (90 parsecs) from Earth.[1] It has an apparent visual magnitude of 4.65,[2] which is bright enough to be seen with the unaided eye under suitable viewing conditions.

This star has a stellar classification of K2 III,[3] with the luminosity class 'III' indicating that this is a giant star that has consumed the hydrogen at its core and evolved away from the main sequence. It has a mass about double that of the Sun[6] and has expanded to 23 times the Sun's radius, giving it a luminosity of 182 times the luminosity of the Sun.[7] The effective temperature of the star's outer envelope is about 4,395 K,[7] which gives the star the orange hue typical of K-type stars.[9] The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is slightly higher than in the Sun.[7]

This star has three optical companions. At an angular separation of 173.1 arcseconds is a magnitude +9.1 star, which is of spectral type K0. A 10th magnitude star is located 221.2 arcseconds away, and the third is a magnitude +9.1 K2 star 321.2 arcseconds away. None of these have been confirmed as a physical companion.[10]

In July 2009, it was discovered that Chi Virginis has a massive planet with a high orbital eccentricity of 0.46. It is orbiting with a period of about 835 days and has a mass at least 11 times greater than Jupiter. There are indications of a second planet orbiting with a period of 130 days, but this has not been firmly established.[11]

The Chi Virginis planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ≥11.09 ± 1 MJ 2.14 ± 0.03 835.477 ± 6 0.462 ± 0.069

See also[edit]

References[edit]

  1. ^ a b c d e f van Leeuwen, F. (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 Gutierrez-Moreno, A. et al. (1966), A System of photometric standards 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G 
  3. ^ a b Buscombe, W. (1962), Spectral classification of Southern fundamental stars, Mount Stromlo Observatory Mimeogram 4, Bibcode:1962MtSOM...4....1B 
  4. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W 
  5. ^ a b da Silva, L. et al. (2006), Basic physical parameters of a selected sample of evolved stars, Astronomy and Astrophysics 458 (2): 609–623, arXiv:astro-ph/0608160, Bibcode:2006A&A...458..609D, doi:10.1051/0004-6361:20065105 
  6. ^ a b Kunitomo, M. et al. (2011), Planet Engulfment by ~1.5–3 M Red Giants, The Astrophysical Journal 737 (2): 66, arXiv:1106.2251, Bibcode:2011ApJ...737...66K, doi:10.1088/0004-637X/737/2/66 
  7. ^ a b c d e f g h i Massarotti, A.; Latham, D. W.; Stefanik, R. P.; Fogel, J. (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 
  8. ^ chi Vir -- Star in double system, SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2011-12-30 
  9. ^ The Colour of Stars, Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, retrieved 2012-01-16 
  10. ^ Eggleton, P. P.; Tokovinin, A. A. (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 
  11. ^ de Medeiros, J. R. et al. (2009), A planet around the evolved intermediate-mass star HD 110014, Astronomy and Astrophysics 504 (2): 617–623, Bibcode:2009A&A...504..617D, doi:10.1051/0004-6361/200911658