 A light curve for Tau Eridani, plotted from TESS data | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03 53 42.70302 |
| Declination | −24° 36′ 44.0309″ |
| Apparent magnitude (V) | 4.63 - 4.65 |
| Characteristics | |
| Spectral type | B6 V |
| U−B color index | −0.48 |
| B−V color index | −0.13 |
| Variable type | SPB |
| Astrometry | |
| Radial velocity (Rv) | +23 km/s |
| Proper motion (μ) | RA: +31.28 mas/yr Dec.: −7.49 mas/yr |
| Parallax (π) | 8.65 ± 0.30 mas |
| Distance | 380 ± 10 ly (116 ± 4 pc) |
| Absolute magnitude (MV) | −0.67 |
| Orbit | |
| 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 | |
| τ Eri A | |
| Mass | 5.0±0.1 M☉ |
| Luminosity | 256 L☉ |
| Surface gravity (log g) | 4.00 cgs |
| Temperature | 11,858 K |
| Rotational velocity (v sin i) | 30 km/s |
| Age | 32.8±9.9 Myr |
| Other designations | |
| τ Eridani, τ Eri, 33 Eridani, CD−24°1945, HD 24587, HIP 18216, HR 1213, SAO 168925. | |
| Database references | |
| SIMBAD | data |
Tau Eridani, Latinized from τ 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. The distance to this system can be estimated via the parallax method, yielding a value of around 380 light years.
This is a single-lined spectroscopic binary star system with an orbital period of about 459 days and an eccentricity of 0.18. The primary component is a B-type main sequence star with a stellar classification of B6 V. Gautier Mathys et al. announced that the star is variable, in 1986. It is a slowly pulsating B-type star that undergoes radial-velocity variation with a frequency of 1.1569 times per day. The star has about five times the mass of the Sun and shines with 256 times the Sun's luminosity. The outer atmosphere has an effective temperature of 11,858 K and may possess a longitudinal magnetic field with a strength of −140±71 G.
References
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- ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
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- ^ Szewczuk, W.; Daszyńska-Daszkiewicz, J. (June 2015), "Identification of pulsational modes in rotating slowly pulsating B-type stars", Monthly Notices of the Royal Astronomical Society, 450 (2): 1585–1603, arXiv:1504.04490, Bibcode:2015MNRAS.450.1585S, doi:10.1093/mnras/stv715.
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