| |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h17m 53.66241s[1] |
| Declination | −33° 47′ 54.0569″[1] |
| Apparent magnitude (V) | 3.56[2] |
| Characteristics | |
| Spectral type | B8V + B9.5V[3] |
| U−B color index | −0.36[2] |
| B−V color index | −0.12[2] |
| Astrometry | |
| Radial velocity (Rv) | +17.6[4] km/s |
| Proper motion (μ) | RA: +62.52[1] mas/yr Dec.: −7.24[1] mas/yr |
| Parallax (π) | 18.33 ± 0.15 mas[1] |
| Distance | 178 ± 1 ly (54.6 ± 0.4 pc) |
| Absolute magnitude (MV) | −0.20[5] |
| Orbit[6] | |
| Period (P) | 5.0103250±0.0000008 d |
| Semi-major axis (a) | 1.902±0.006 mas |
| Eccentricity (e) | 0 |
| Inclination (i) | 146.2±0.1° |
| Periastron epoch (T) | 2454407.7214 ± 0.002 JD |
| Semi-amplitude (K1) (primary) | 62.68±0.17[7] km/s |
| Semi-amplitude (K2) (secondary) | 64.70±0.15[7] km/s |
| Details[6] | |
| υ4 Eri A | |
| Mass | 3.17±0.07 M☉ |
| Radius | 2.32±0.18 R☉ |
| Luminosity | 100.6±4.3 L☉ |
| Surface gravity (log g) | 4.21±0.07 cgs |
| Temperature | 12,930±440[8] K |
| Rotational velocity (v sin i) | 19[8] km/s |
| Age | 146[8] Myr |
| υ4 Eri B | |
| Mass | 3.07±0.07 M☉ |
| Radius | 2.32±0.18 R☉ |
| Luminosity | 87.4±3.3 L☉ |
| Surface gravity (log g) | 4.21±0.07 cgs |
| Temperature | 12,250 K |
| Other designations | |
υ4 Eri, 41 Eridani, CD−34° 1614, HD 27376, HIP 20042, HR 1347, SAO 194902.[9] | |
| Database references | |
| SIMBAD | data |
Upsilon4 Eridani is a close binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.56.[2] Based upon parallax measurements, the pair are located around 54.6 parsecs (178 ly) from the Sun.[1]
This is a double-lined spectroscopic binary star system,[10] which means that the Doppler-shifted spectral lines of both components can be distinguished. The pair have a circular orbit with a period of five days. The system is composed of two B-type main-sequence stars: one has a stellar classification of B8V and the other B9.5V.[3] Both stars show HgMn peculiarities in their spectrum,[7] and their properties are nearly identical.[6] The spin rate of the two stars is synchronized to their orbital period.[6] It is possible that a nearby K-type star is also related.[3]
{{cite web}}: CS1 maint: postscript (link)
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