HD 57821
Star in the constellation Canis Major
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HD 57821 is a single[9] star in the southern constellation of Canis Major. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.94.[1] Based on parallax measurements, the distance to this object is approximately 480 light years. It is drifting further away with a radial velocity of +33 km/s, having come to within 71 light-years some 4.3 million years ago.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Canis Major[1] |
| Right ascension | 07h 22m 13.52901s[2] |
| Declination | â19° 00â² 59.7646â³[2] |
| Apparent magnitude (V) | 4.94[1] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | B5 II/III[4] or B7 IV[5] |
| BâV color index | â0.039±0.024[1] |
| Astrometry | |
| Radial velocity (Rv) | +32.9±1.6[1] km/s |
| Proper motion (μ) | RA: â1.69[2] mas/yr Dec.: +6.91[2] mas/yr |
| Parallax (Ï) | 6.78±0.26 mas[2] |
| Distance | 480 ± 20 ly (147 ± 6 pc) |
| Absolute magnitude (MV) | â0.90[1] |
| Details | |
| Mass | 4.12±0.08[3] Mâ |
| Radius | 4.7[6] Râ |
| Luminosity | 489+43 â40[3] Lâ |
| Temperature | 12,445±86[3] K |
| Rotational velocity (v sin i) | 116[3] km/s |
| Age | 291[7] Myr |
| Other designations | |
| BDâ18°1806, FK5 2570, HD 57821, HIP 35727, HR 2812, SAO 152776[8] | |
| Database references | |
| SIMBAD | data |
The stellar classification of this star is B5 II/III,[4] which matches the spectrum of a giant/bright giant although stellar models suggest it may still be on the main sequence.[3] It has over four[3] times the mass of the Sun and is 291[7] million years old. The star has a high rate of spin, showing a projected rotational velocity of 116 km/s.[3] It is radiating around 489[3] times the luminosity of the Sun from its photosphere at an effective temperature of 12,445 K.[3]