Tau7 Eridani
Star in the constellation Eridanus
From Wikipedia, the free encyclopedia
Tau7 Eridani is a solitary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 5.235.[2] Using the parallax method, the distance to this star can be estimated as around 251 light years.[1]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 47m 39.65058s[1] |
| Declination | −23° 52′ 28.8352″[1] |
| Apparent magnitude (V) | 5.235[2] |
| Characteristics | |
| Spectral type | A3 Vs[3] |
| U−B color index | +0.168[2] |
| B−V color index | +0.067[2] |
| Astrometry | |
| Radial velocity (Rv) | 28.4±0.5[4] km/s |
| Proper motion (μ) | RA: +47.46[1] mas/yr Dec.: +49.10[1] mas/yr |
| Parallax (π) | 13.00±0.28 mas[1] |
| Distance | 251 ± 5 ly (77 ± 2 pc) |
| Absolute magnitude (MV) | +0.81[5] |
| Details | |
| τ7 Eri A | |
| Mass | 2.03[6] M☉ |
| Luminosity | 37.6[7] L☉ |
| Surface gravity (log g) | 3.86±0.2[8] cgs |
| Temperature | 8,740±200[8] K |
| Rotational velocity (v sin i) | 18[8] km/s |
| Age | 387[6] Myr |
| Other designations | |
| τ7 Eridani, τ7 Eri, 28 Eridani, CD−24°1877, HD 23878, HIP 17717, HR 1181, SAO 168836[9] | |
| Database references | |
| SIMBAD | data |
This is an A-type main sequence star with a stellar classification of A3 Vs,[3] where the 's' indicates it has narrow absorption lines. It may be a chemically peculiar Am star, which means it displays unusual abundances of certain elements in its surface layers. Tau7 Eridani appears to be a low amplitude variable that displays slight fluctuations in luminosity over a period of 7.17 days. It is slowly rotating with a projected rotational velocity of 18 km/s,[8] and is around 387 million years old.[6]