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Suggest pagesChi Virginis
 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] |
| 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 | |
| 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]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | ≥11.09 ± 1 MJ | 2.14 ± 0.03 | 835.477 ± 6 | 0.462 ± 0.069 |
[edit] See also
[edit] References
- ^ a b c d e f van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. Bibcode 2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- ^ a b c d Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode 1966PDAUC...1....1G
- ^ a b Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram 4, Bibcode 1962MtSOM...4....1B
- ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode 1953GCRV..C......0W
- ^ a b da Silva, L. et al. (November 2006), "Basic physical parameters of a selected sample of evolved stars", Astronomy and Astrophysics 458 (2): 609–623, Bibcode 2006A&A...458..609D, doi:10.1051/0004-6361:20065105
- ^ a b Kunitomo, M. et al. (August 2011), "Planet Engulfment by ~1.5-3 M sun Red Giants", The Astrophysical Journal 737 (2): 66, Bibcode 2011ApJ...737...66K, doi:10.1088/0004-637X/737/2/66
- ^ a b c d e f g h i 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
- ^ "chi Vir -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Chi+Virginis, retrieved 2011-12-30
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ^ 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, Bibcode 2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x
- ^ de Medeiros, J. R. et al. (September 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
