p Eridani
p Eridani is a binary star system in the constellation of Eridanus (the River) whose distance from the Sun is 26.7 light-years based upon parallax. It was found to be a double star in December 1825 by James Dunlop in Australia at his home at Paramatta, now spelt Parramatta. It is visible to the naked eye as a dim, orange-hued star. The system is moving further from the Earth with a heliocentric radial velocity of about +20 km/s.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Eridanus |
| A | |
| Right ascension | 01h 39m 47.813s |
| Declination | −56° 11′ 35.94″ |
| Apparent magnitude (V) | 5.76 |
| B | |
| Right ascension | 01h 39m 47.565s |
| Declination | −56° 11′ 47.21″ |
| Apparent magnitude (V) | 5.87 |
| Characteristics | |
| Spectral type | K2V + K2V |
| U−B color index | +0.59 / +0.53 |
| B−V color index | +0.90 / +0.87 |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +21.74±0.12 km/s |
| Proper motion (μ) | RA: 262.615 mas/yr Dec.: 14.961 mas/yr |
| Parallax (π) | 122.1088 ± 0.0365 mas |
| Distance | 26.710 ± 0.008 ly (8.189 ± 0.002 pc) |
| Absolute magnitude (MV) | 6.25 |
| B | |
| Radial velocity (Rv) | +20.15±0.12 km/s |
| Proper motion (μ) | RA: 309.230 mas/yr Dec.: 10.815 mas/yr |
| Parallax (π) | 122.0035 ± 0.0319 mas |
| Distance | 26.733 ± 0.007 ly (8.196 ± 0.002 pc) |
| Absolute magnitude (MV) | 6.27 |
| Orbit | |
| Period (P) | 475.2 yr |
| Semi-major axis (a) | 7.826″ |
| Eccentricity (e) | 0.5344 |
| Inclination (i) | 140.5° |
| Longitude of the node (Ω) | 13.7° |
| Periastron epoch (T) | 1811.90 |
| Argument of periastron (ω) (secondary) | 18.6° |
| Details | |
| p Eri A | |
| Mass | 0.78 M☉ |
| Radius | 0.75 R☉ |
| Luminosity | 0.339 L☉ |
| Surface gravity (log g) | 4.63 cgs |
| Temperature | 5,077 K |
| Metallicity [Fe/H] | –0.24 dex |
| Rotation | 30 days |
| Age | 4.94 Gyr |
| p Eri B | |
| Mass | 0.77 M☉ |
| Radius | 0.77 R☉ |
| Luminosity | 0.311 L☉ |
| Surface gravity (log g) | 4.65 cgs |
| Temperature | 5,117 K |
| Metallicity [Fe/H] | –0.19 dex |
| Rotation | 39 days |
| Age | 1.96 Gyr |
| Other designations | |
| p Eri A: HD 10360, HR 486, LTT 903 | |
| p Eri B: HD 10361, HR 487, LTT 902 | |
| Database references | |
| SIMBAD | data |
| p Eri A | |
| p Eri B | |
This system consists of a pair of near identical K-type main-sequence stars with stellar classifications of K2V. Component A has visual magnitude 5.87, while component B is magnitude 5.76. They orbit each other with a period of 475.2 years, an eccentricity of 0.53, and a semimajor axis of 7.8″.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.