![]() ![]() The position of Sirius (circled). |
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Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
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Constellation | Canis Major |
Pronunciation | /ˈsɪriəs/ |
Right ascension | 06 |
Declination | −16° 42′ 58.017″ |
Apparent magnitude (V) | −1.46 (A) |
Characteristics | |
Spectral type | A1V (A) |
U−B color index | −0.05 (A) |
B−V color index | 0.01 (A) |
Astrometry | |
Radial velocity (Rv) | −7.6 km/s |
Proper motion (μ) | RA: −546.05 mas/yr |
Parallax (π) | 379.21 ± 1.58mas |
Distance | 8.60 ± 0.04 ly (2.64 ± 0.01 pc) |
Absolute magnitude (MV) | 1.42 (A) |
Orbit | |
Companion | α CMa B |
Period (P) | 50.090 ± 0.055 yr |
Semimajor axis (a) | 7.50 ± 0.04" |
Eccentricity (e) | 0.5923 ± 0.0019 |
Inclination (i) | 136.53 ± 0.43° |
Longitude of the node (Ω) | 44.57 ± 0.44° |
Periastron epoch (T) | 1894.130 ± 0.015 |
Argument of periastron (ω) (secondary) |
147.27 ± 0.54° |
Details | |
α CMa A | |
Mass | 2.02M☉ |
Radius | 1.711R☉ |
Luminosity | 25.4L☉ |
Surface gravity (log g) | 4.33 |
Temperature | 9,940K |
Metallicity [Fe/H] | 0.50dex |
Rotation | 16 km/s |
Age | 2–3 × 10 years |
α CMa B | |
Mass | 0.978M☉ |
Radius | 0.0084 ± 3%R☉ |
Luminosity | 0.026L☉ |
Surface gravity (log g) | 8.57 |
Temperature | 25,200K |
Other designations | |
System: Dog Star, Aschere, Canicula, Al Shira, Sothis,
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