Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Eridanus |
Right ascension | 03h 53m 42.70302s[2] |
Declination | −24° 36′ 44.0309″[2] |
Apparent magnitude (V) | 4.63 - 4.65[3] |
Characteristics | |
Spectral type | B6 V[4] |
U−B color index | −0.48[5] |
B−V color index | −0.13[5] |
Variable type | SPB[3] |
Astrometry | |
Radial velocity (Rv) | +23[6] km/s |
Proper motion (μ) | RA: +31.28[2] mas/yr Dec.: −7.49[2] mas/yr |
Parallax (π) | 8.65 ± 0.30 mas[2] |
Distance | 380 ± 10 ly (116 ± 4 pc) |
Absolute magnitude (MV) | −0.67[7] |
Orbit[8] | |
Period (P) | 459±4 d |
Eccentricity (e) | 0.18±0.02 |
Periastron epoch (T) | 2450954±7 JD |
Argument of periastron (ω) (secondary) | 106±5° |
Semi-amplitude (K1) (primary) | 21.7±0.4 km/s |
Details | |
τ8 Eri A | |
Mass | 5.0±0.1[9] M☉ |
Luminosity | 256[10] L☉ |
Surface gravity (log g) | 4.00[11] cgs |
Temperature | 11,858[10] K |
Rotational velocity (v sin i) | 30[4] km/s |
Age | 32.8±9.9[9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Tau8 Eridani, Latinized from τ8 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.65.[5] The distance to this system can be estimated via the parallax method, yielding a value of around 380 light years.[2]
This is a single-lined[13] spectroscopic binary star system with an orbital period of about 459 days and an eccentricity of 0.18.[8] The primary component is a B-type main sequence star with a stellar classification of B6 V.[4] It is a slowly pulsating B-type star that undergoes radial-velocity variation with a frequency of 1.1569 times per day.[13] The star has about five[9] times the mass of the Sun and shines with 256 times the Sun's luminosity.[10] The outer atmosphere has an effective temperature of 11,858[10] K and may possess a longitudinal magnetic field with a strength of −140±71 G.[14]