Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Eridanus |
Right ascension | 02h 45m 06.18710s[1] |
Declination | −18° 34′ 21.2149″[1] |
Apparent magnitude (V) | 4.46[2] |
Characteristics | |
Spectral type | F7V[3] |
U−B color index | +0.00[2] |
B−V color index | +0.48[2] |
Astrometry | |
Radial velocity (Rv) | +25.9[4] km/s |
Proper motion (μ) | RA: +334.20[1] mas/yr Dec.: +37.19[1] mas/yr |
Parallax (π) | 70.32 ± 1.83 mas[1] |
Distance | 46 ± 1 ly (14.2 ± 0.4 pc) |
Absolute magnitude (MV) | +3.68[5] |
Orbit[6] | |
Period (P) | 958 d |
Eccentricity (e) | 0.45 |
Periastron epoch (T) | 39391.9 |
Argument of periastron (ω) (secondary) | 180° |
Details | |
Mass | 1.15[7] M☉ |
Surface gravity (log g) | 4.34[8] cgs |
Temperature | 6,231[8] K |
Metallicity [Fe/H] | −0.08 ± 0.06[8] dex |
Rotation | 3.847 d[9] |
Rotational velocity (v sin i) | 28.02[10] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Tau1 Eridani, Latinized from τ1 Eridani, is a binary star[6] system in the constellation Eridanus. It has an apparent magnitude of 4.46, making it visible to the naked eye in suitably dark conditions. This a spectroscopic binary with an orbital period of 958 days.[6] It is located about 46 light years from the Earth.[1] At present, the system is moving away from the Sun with a radial velocity of +26 km/s.[4] About 305,000 years ago, it made perihelion passage at an estimated distance of 30.5 ly (9.35 pc).[12]
Tau1 Eridani was a latter designation of 90 Ceti.[13]
A moderate far-infrared excess was observed for this star system, in the 12μm, 25μm, 60μm and 100μm wavelengths, by the Infrared Astronomical Satellite (IRAS), and published in 1993.[14] This discovery was subsequently interpreted as indicating a debris disk with a radius near to 500 AU. It was further speculated that, if the star system had been observed at longer wavelengths, it was likely the debris disk would have been seen to have a radius considerably wider than 500 AU.[15]
Later observations made by the Spitzer Space Telescope, published in 2004, detected no substantial infrared excess around the stars, within the 14-35μm range of wavelengths.[16]