  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 36m 41.03758s[1] |
| Declination | −19° 15′ 21.1659″[1] |
| Apparent magnitude (V) | 3.96[2] |
| Characteristics | |
| Spectral type | K1 III[2] |
| Astrometry | |
| Radial velocity (Rv) | +2.57±0.14[3] km/s |
| Proper motion (μ) | RA: +62.57±0.15mas/yr[1] Dec.: −69.97±0.16mas/yr[1] |
| Parallax (π) | 50.63±0.23 mas[1] |
| Distance | 64.4 ± 0.3 ly (19.75 ± 0.09 pc) |
| Absolute magnitude (MV) | 2.47[2] |
| Details | |
| Mass | 1.439±0.047[4] M☉ |
| Radius | 5.198±0.060[4] R☉ |
| Luminosity | 13.2±0.7[4] L☉ |
| Surface gravity (log g) | 3.165±0.005[5] cgs |
| Temperature | 4,790±27[5] K |
| Metallicity [Fe/H] | 0.21±0.10[5] dex |
| Rotational velocity (v sin i) | 1.97±0.23[3] km/s |
| Age | 4.6±0.7[5] Gyr |
| Other designations | |
| ν2 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 |
Nu2 Canis Majoris (ν2 Canis Majoris) is a single[6]star in the southernconstellation ofCanis Major. It is a coolgiant with two confirmedexoplanets.
With anapparent visual magnitude of 3.96,[2] it is bright enough to be seen with the naked eye to the southwest ofSirius. It has an annualparallax shift of around 50.63 mas as seen from Earth,[1] thus this system is about 64.4 light years from theSun, a parallax well within the error margins of the figure later given by theGaia space observatory data release 2, namely 50.471 ± 0.4168.[7]
It is an evolvedK-type giant around 4.6 billion years old.[5] Around 1.3 times as massive as the Sun, it has expanded to around 5.2 times the Sun's diameter and 13 times its luminosity.[4]
InChinese astronomy, ν2 Canis Majoris is called 野雞,Pinyin: Yějī, meaningWild Cockerel, because this star is marking itself and stand alone inWild Cockerel asterism,Well mansion (see :Chinese constellation).[8] 野雞 (Yějī), westernized intoYa Ke. According to R.H. Allen opinion, the nameYa Ke is asterism consistingο1 Canis Majoris andπ Canis Majoris, with other small stars in the body of the Dog[9]
By measuring periodic variations in theradial velocity of the host star between 2009 and 2010, the Pan-Pacific Planet Search program was able to identify a planet orbiting Nu2 Canis Majoris. An orbital fit produced a minimum mass estimate of2.6±0.6 MJwith anorbital period of 2.1 years and aneccentricity of 0.23. Star spots were ruled out as a source for the signal with a false-alarm probability of 98.7%.[10] Further observations through 2019 detected the planet, as well as a secondary planet c in a 4:3orbital resonance with planet b.[11]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.940±0.064 MJ | 1.800±0.033 | 736.9 | 0.055 | — | — |
| c | ≥0.912±0.067 MJ | 2.205±0.046 | 988.9 | 0.046 | — | — |
