10 Canis Majoris
Star in the constellation Canis Major
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10 Canis Majoris is a single[14] variable star in the southern constellation of Canis Major,[13] located roughly 1,980 light years away from the Sun.[2] It has the variable star designation FT Canis Majoris; 10 Canis Majoris is the Flamsteed designation. This body is visible to the naked eye as a faint, 5th-magnitude blue-white hued star. It is moving away from the Earth with a heliocentric radial velocity of +34 km/s.[7]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 44m 28.46710s[2] |
| Declination | â31° 04â² 13.8923â³[2] |
| Apparent magnitude (V) | 5.13â5.44[3] |
| Characteristics | |
| Spectral type | B2 V[4] or B2 IIIe[5] |
| BâV color index | â0.127±0.005[6] |
| Variable type | Be[3] |
| Astrometry | |
| Radial velocity (Rv) | +34.0±4.2[7] km/s |
| Proper motion (μ) | RA: â3.286[2] mas/yr Dec.: +4.201[2] mas/yr |
| Parallax (Ï) | 1.6454±0.0722 mas[2] |
| Distance | 1,980 ± 90 ly (610 ± 30 pc) |
| Details | |
| Mass | 19.2±0.1[8] Mâ |
| Radius | 10.0[9] Râ |
| Luminosity | 44,463+35,336 â19,689[10] Lâ |
| Surface gravity (log g) | 3.76±0.17[10] cgs |
| Temperature | 25,350±1,030[10] K |
| Rotation | 2.63 d[11] |
| Rotational velocity (v sin i) | 205±5[12] km/s |
| Age | 8.2±0.1[8] Myr |
| Other designations | |
| 10 CMa, FT Canis Majoris, CDâ30°3484, GC 8827, HD 48917, HIP 32292, HR 2492, SAO 197149, CCDM 06445-3104, WDS J06445-3104[13] | |
| Database references | |
| SIMBAD | data |
This is a massive Be star[9] with a stellar classification of B2 V,[4] matching a B-type main-sequence star. Hiltner et al. (1969) found a giant class of B2 IIIe,[5] which is still in use with some studies.[14][3] The star is spinning rapidly with a projected rotational velocity of 205 km/s[12] and a rotational period of 2.63 days.[11] This is giving it an oblate shape with an equatorial bulge that is 5% larger than the polar radius.[15] The axis of rotation is inclined by an angle of 45° to the line of sight from the Earth.[9]
In 1968, Alejandro Feinstein announced that the star is variable, based on observations from 1963-1965.[16] It was given its variable star designation in 1973.[17] Samus et al. (2017) classify it as a Be-type variable star that ranges from a peak visual magnitude of 5.13 down to 5.44 with a rotationally-modulated period of 2.63 days.[3][11]
10 Canis Majoris is 8.2[8] million years old with 19.2[8] times the mass of the Sun and 10[9] times the Sun's radius. It is radiating around 44,000[10] times the luminosity of the Sun from its photosphere at an effective temperature of 25,000 K.[10] There is a magnitude 12.58 visual companion at an angular separation of 37.3Ⳡalong a position angle of 99°, as of 2015.[18]