Chi Virginis
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Virgo |
Right ascension | 12h 39m 14.76696s[1] |
Declination | −07° 59′ 44.0338″[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) | −18.11±0.07[4] km/s |
Proper motion ( | RA: −77.223[1] mas/yr Dec.: −24.409[1] mas/yr |
Parallax ( | 10.3526 ± 0.1151 mas[1] |
Distance | 315 ± 4 ly (97 ± 1 pc) |
Absolute magnitude (MV) | −0.29±0.19[5] |
Details[4] | |
Mass | 2.28±0.35 M☉ |
Radius | 20.15±2 R☉ |
Luminosity | 107 L☉ |
Surface gravity (log g) | 2.15±0.1 cgs |
Temperature | 4,559±53 K |
Metallicity | 0.05±0.1 |
Rotational velocity (v sin i) | 2.52±0.45 km/s |
Age | 0.86±0.34[5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
Chi Virginis (
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 and has expanded to 20 times the Sun's radius, giving it a luminosity of 107 times the luminosity of the Sun. The effective temperature of the star's outer envelope is about 4,559 K,[4] which gives the star the orange hue typical of K-type stars.[7] The abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is slightly higher than in the Sun.[8][4]
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.[9]
Planetary system
[edit]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.[10]
In May 2015, the existence of a second planet candidate, HD 110014 c , (Chi Virginis c, about three times the mass of Jupiter and having an orbit roughly that of Venus) was announced by Chilean astronomer Maritza Soto. The two-planet model could not be confirmed, and the radial velocity variations attributed to the second planet might instead be caused by a starspot.[11] A 2021 review of planets around giant stars lists this second planet as "questionable".[12]
Companion (in order from star) |
Mass | Semimajor axis ( |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
c (unconfirmed) | ≥3.1±0.4 MJ | 0.64±0.003 | 130.0±0.9 | 0.44±0.2 | — | — |
b | ≥10.7±1.0 MJ | 2.31±0.04 | 882.6±21.5 | 0.26±0.1 | — | — |
See also
[edit]References
[edit]- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c Gutierrez-Moreno, A.; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G
- ^ a b Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram, 4: 1, Bibcode:1962MtSOM...4....1B
- ^ a b c d Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015-02-01). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy and Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. ISSN 0004-6361. Chi Virginis' database entry at VizieR.
- ^ 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, S2CID 9341088
- ^ "chi Vir -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2011-12-30
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
- ^ 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, S2CID 121883397
- ^ 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, S2CID 14878976
- ^ 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
- ^ a b Soto, M. G.; et al. (August 2015). "RAFT - I. Discovery of new planetary candidates and updated orbits from archival FEROS spectra". Monthly Notices of the Royal Astronomical Society. 451 (3): 3131–3144. arXiv:1505.04796. Bibcode:2015MNRAS.451.3131S. doi:10.1093/mnras/stv1144. S2CID 49332927.
- ^ Döllinger, M. P.; Hartmann, M. (September 2021). "A Sanity Check for Planets around Evolved Stars". The Astrophysical Journal Supplement Series. 256 (1): 10. Bibcode:2021ApJS..256...10D. doi:10.3847/1538-4365/ac081a. S2CID 237369556.