Location of ν Canis Majoris (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06 36 41.03758 |
| Declination | −19° 15′ 21.1659″ |
| Apparent magnitude (V) | 3.96 |
| Characteristics | |
| Spectral type | K1 III |
| Astrometry | |
| Radial velocity (Rv) | +2.57±0.14 km/s |
| Proper motion (μ) | RA: +62.57±0.15 mas/yr Dec.: −69.97±0.16 mas/yr |
| Parallax (π) | 50.63 ± 0.23 mas |
| Distance | 64.4 ± 0.3 ly (19.75 ± 0.09 pc) |
| Absolute magnitude (MV) | 2.47 |
| Details | |
| Mass | 1.3±0.1 M☉ |
| Radius | 4.9±0.1 R☉ |
| Luminosity | 11.3±0.1 L☉ |
| Surface gravity (log g) | 3.18±0.03 cgs |
| Temperature | 4,790±27 K |
| Metallicity | 0.21±0.10 dex |
| Rotational velocity (v sin i) | 1.97±0.23 km/s |
| Age | 4.6±0.7 Gyr |
| Other designations | |
| ν CMa, 7 CMa, BD−19°1502, FK5 2510, GC 8624, GJ 239.1, HD 47205, HIP 31592, HR 2429, SAO 151702 | |
| Database references | |
| SIMBAD | data |
Nu Canis Majoris (ν Canis Majoris) is a single star in the southern constellation of Canis Major. It is a cool giant with two confirmed exoplanets.
Characteristics
With an apparent visual magnitude of 3.96, it is bright enough to be seen with the naked eye to the southwest of Sirius. It has an annual parallax shift of around 50.63 mas as seen from Earth, thus this system is about 64.4 light years from the Sun, a parallax well within the error margins of the figure later given by the Gaia space observatory data release 2, namely 50.471 ± 0.4168.
It is an evolved K-type giant around 4.6 billion years old. Around 1.3 times as massive as the Sun, it has expanded to around 4.9 times the Sun's diameter and 11 times its luminosity. In 2011, it was found to have a planet.
Chinese name
In Chinese astronomy, ν Canis Majoris is called 野雞, Pinyin: Yějī, meaning Wild Cockerel, because this star is marking itself and stand alone in Wild Cockerel asterism, Well mansion (see : Chinese constellation). 野雞 (Yějī), westernized into Ya Ke. According to R.H. Allen opinion, the name Ya Ke is asterism consisting ο Canis Majoris and π Canis Majoris, with other small stars in the body of the Dog
Planetary system
By measuring periodic variations in the radial velocity of the host star between 2009 and 2010, the Pan-Pacific Planet Search program was able to identify a planet orbiting Nu Canis Majoris. An orbital fit produced a minimum mass estimate of 2.6±0.6 MJwith an orbital period of 2.1 years and an eccentricity of 0.23. Star spots were ruled out as a source for the signal with a false-alarm probability of 98.7%. Further observations through 2019 detected the planet, as well as a secondary planet c in a 4:3 orbital resonance with planet b.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.895 MJ | 1.761 | 736.9 | 0.055 | — | — |
| c | ≥0.609 MJ | 2.143 | 988.9 | 0.046 | — | — |
References
- ^ 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. S2CID 18759600. Vizier catalog entry
- ^ Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi:10.1051/0004-6361:20041042-1.
- ^ Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, S2CID 53666931.
- ^ Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
- 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:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Wittenmyer; et al. (2011). "The Pan-Pacific Planet Search. I. A Giant Planet Orbiting 7 CMa". The Astrophysical Journal. 743 (2): 184. arXiv:1111.1007. Bibcode:2011ApJ...743..184W. doi:10.1088/0004-637X/743/2/184. S2CID 26948630.
- (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日 Archived 2011-08-22 at the Wayback Machine
- Richard Hinckley Allen: Star Names — Their Lore and Meaning: Canis Major
- ^ Luque, R.; Trifonov, T.; Reffert, S.; Quirrenbach, A.; Lee, M. H.; Albrecht, S.; Andersen, M. Fredslund; Antoci, V.; Grundahl, F.; Schwab, C.; Wolthoff, V. (13 October 2019). "Precise radial velocities of giant stars XIII. A second Jupiter orbiting in 4:3 resonance in the 7 CMa system". Astronomy & Astrophysics. A136: 631. arXiv:1910.05853. Bibcode:2019A&A...631A.136L. doi:10.1051/0004-6361/201936464. S2CID 204512658.
External links
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