Chi 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] 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 | |
| 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] But on 19 August 2015, the existence of a second planet (about three times bigger than Jupiter and having an orbit roughly that of Venus) was confirmed by a Chilean astronomer.[12]
| 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
References
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- ↑ 2.0 2.1 2.2 2.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 6.0 6.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://m.gadgets.ndtv.com/science/news/astronomer-discovers-planet-3-times-as-large-as-jupiter-730075
