Procyon
Procyon (/ˈproʊsi.ɒn/) is the brightest star in the constellation of Canis Minor and usually the eighth-brightest star in the night sky, with an apparent visual magnitude of 0.34. It has the Bayer designation α Canis Minoris, which is Latinized to Alpha Canis Minoris, and abbreviated α CMi or Alpha CMi, respectively. As determined by the European Space Agency Hipparcos astrometry satellite, this system lies at a distance of just 11.46 light-years (3.51 parsecs), and is therefore one of Earth's nearest stellar neighbors.
The position of Procyon | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Minor |
| Pronunciation | /ˈproʊsi.ɒn/ PROH-see-on |
| Right ascension | 07h 39m 18.11950s |
| Declination | +05° 13′ 29.9552″ |
| Apparent magnitude (V) | 0.34 (A) / 10.7 (B) |
| Characteristics | |
| Spectral type | F5 IV–V + DQZ |
| U−B color index | +0.00 |
| B−V color index | +0.42 |
| Variable type | suspected (A) |
| Astrometry | |
| Radial velocity (Rv) | −3.2 km/s |
| Proper motion (μ) | RA: −714.590 mas/yr Dec.: −1036.80 mas/yr |
| Parallax (π) | 284.56 ± 1.26 mas |
| Distance | 11.46 ± 0.05 ly (3.51 ± 0.02 pc) |
| Absolute magnitude (MV) | 2.66/13.0 |
| Details | |
| Procyon A | |
| Mass | 1.499±0.031 M☉ |
| Radius | 2.048±0.025 R☉ |
| Luminosity | 6.93 L☉ |
| Surface gravity (log g) | 3.96 cgs |
| Temperature | 6,530±50 K |
| Metallicity [Fe/H] | −0.05±0.03 dex |
| Rotation | 23 days |
| Rotational velocity (v sin i) | 3.16±0.50 km/s |
| Age | 1.87±0.13 Gyr |
| Procyon B | |
| Mass | 0.602±0.015 M☉ |
| Radius | 0.01234±0.00032 R☉ |
| Luminosity | 0.00049 L☉ |
| Surface gravity (log g) | 8.0 cgs |
| Temperature | 7,740±50 K |
| Age | 1.37 Gyr |
| Orbit | |
| Companion | Procyon B |
| Period (P) | 40.840 ± 0.022 yr |
| Semi-major axis (a) | 4.3075 ± 0.0016″ |
| Eccentricity (e) | 0.39785 ± 0.00025 |
| Inclination (i) | 31.408 ± 0.050° |
| Longitude of the node (Ω) | 100.683 ± 0.095° |
| Periastron epoch (T) | 1,968.076 ± 0.023 |
| Argument of periastron (ω) (secondary) | 89.23 ± 0.11° |
| Other designations | |
Elgomaisa, α Canis Minoris, 10 Canis Minoris, BD+05°1739, GJ 280, HD 61421, HIP 37279, HR 2943, SAO 115756, LHS 233 | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
A binary star system, Procyon consists of a white-hued main-sequence star of spectral type F5 IV–V, designated component A, in orbit with a faint white dwarf companion of spectral type DQZ, named Procyon B. The pair orbit each other with a period of 40.84 years and an eccentricity of 0.4.