Upsilon4 Eridani
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 17m 53.66241s |
| Declination | −33° 47′ 54.0569″ |
| Apparent magnitude (V) | 3.56 |
| Characteristics | |
| Spectral type | B8V + B9.5V |
| U−B color index | −0.36 |
| B−V color index | −0.12 |
| Astrometry | |
| Radial velocity (Rv) | +17.6 km/s |
| Proper motion (μ) |
RA: +62.52 mas/yr Dec.: −7.24 mas/yr |
| Parallax (π) | 18.33 ± 0.15mas |
| Distance | 178 ± 1 ly (54.6 ± 0.4 pc) |
| Orbit | |
| Period (P) | 5.010315 ± 0.000012 days |
| Eccentricity (e) | 0.0001±0.0019 |
| Periastron epoch (T) | 54407.2201 ± 0.0012 JD |
|
Semi-amplitude (K1) (primary) |
62.68±0.17 km/s |
|
Semi-amplitude (K2) (secondary) |
64.70±0.15 km/s |
| Details | |
| υ4 Eri A | |
| Mass | 3.85 M☉ |
| Surface gravity (log g) | 4.23±0.14 cgs |
| Temperature | 12,930±440 K |
| Rotational velocity (v sin i) | 19 km/s |
| Age | 146 Myr |
| υ4 Eri B | |
| Temperature | 12,250 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Upsilon4 Eridani is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.56. Based upon parallax measurements, the pair are located around 54.6 parsecs (178 ly) from the Sun.
This is a double-lined spectroscopic binary star system, which means that the Doppler-shifted spectral lines of both components can be distinguished. The system is composed of two B-type main-sequence stars: one has a stellar classification of B8V and the other B9.5V. Both stars show HgMn peculiarities in their spectrum. It is possible that a nearby K-type star is also related.
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