Kappa Canis Majoris
Star in the constellation Canis Major
From Wikipedia, the free encyclopedia
Kappa Canis Majoris is a solitary,[11] blue-white hued star in the constellation Canis Major. Its name is a Bayer designation that is Latinized from κ Canis Majoris, and abbreviated Kappa CMa or κ CMa. This star is visible to the naked eye with an apparent visual magnitude of +3.87.[2] Based upon an annual parallax shift of 7.70 mas as seen from Earth,[1] this star is located about 660 light years from the Sun. It is receding from the Sun with a line of sight velocity of +14 km/s.[4]
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 49m 50.45933s[1] |
| Declination | â32° 30â² 30.5225â³[1] |
| Apparent magnitude (V) | +3.87[2] |
| Characteristics | |
| Spectral type | B1.5 Ve[3] |
| UâB color index | â0.97[2] |
| BâV color index | â0.20[2] |
| Variable type | γ Cas[3] |
| Astrometry | |
| Radial velocity (Rv) | +14.0±4.1[4] km/s |
| Proper motion (μ) | RA: â8.84[1] mas/yr Dec.: +3.73[1] mas/yr |
| Parallax (Ï) | 4.95±0.12 mas[1] |
| Distance | 660 ± 20 ly (202 ± 5 pc) |
| Absolute magnitude (MV) | â3.03[5] |
| Details | |
| Mass | 12.2±0.3[6] Mâ |
| Radius | 5.9[7] Râ |
| Luminosity (bolometric) | 18,876[8] Lâ |
| Surface gravity (log g) | 4.07[7] cgs |
| Temperature | 24,600[7] K |
| Rotational velocity (v sin i) | 290±6[9] km/s |
| Age | 13.3±1.2[6] Myr |
| Other designations | |
| κ CMa, 13 Canis Majoris, CDâ32°3404, FK5 1180, GC 8946, HD 50013, HIP 32759, HR 2538, SAO 197258[10] | |
| Database references | |
| SIMBAD | data |
This is a massive B-type main-sequence star with a stellar classification of B1.5 Ve,[3] although Hiltner et al. (1969) classified it as B1.5 IVe[14] suggesting it is a subgiant star. The 'e' suffix indicates it is a rapidly rotating Be star with a circumstellar decretion disk of heated gas.[7] The radius of the emitting disk is about 0.20±0.06 AU, or about 3.7 times the radius of the star.[15] It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +3.4 to +3.97.[3] The star became 50% brighter between 1963 and 1978, increasing from magnitude 3.96 or so to 3.52.[16]
This star is about 13.3[6] million years old and spinning with a projected rotational velocity of 290 km/s.[9] It has 6 times the radius of the Sun and 12 times the Sun's mass. The star is emitting 18,876[8] times the luminosity of the Sun from its photosphere at an effective temperature of 24,600 K.[7]
Naming
In Chinese, å¼§ç¢ (Hú ShÇ), meaning Bow and Arrow,[17] refers to an asterism consisting of κ Canis Majoris, δ Canis Majoris, η Canis Majoris, HD 63032, HD 65456, ο Puppis, k Puppis, ε Canis Majoris and Ï Puppis. Consequently, κ Canis Majoris itself is known as 弧ç¢å « (Hú ShÇ bÄ, English: the Eighth Star of Bow and Arrow.)[18]