Zeta Eridani
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 15m 50.02656s |
| Declination | −08° 49′ 11.0220″ |
| Apparent magnitude (V) | 4.80 |
| Characteristics | |
| Spectral type | kA4hA9mA9V |
| U−B color index | +0.07 |
| B−V color index | +0.24 |
| Astrometry | |
| Radial velocity (Rv) | −5.8±4.2 km/s |
| Proper motion (μ) |
RA: −0.35 mas/yr Dec.: +46.10 mas/yr |
| Parallax (π) | 29.72 ± 0.29mas |
| Distance | 110 ± 1 ly (33.6 ± 0.3 pc) |
| Absolute magnitude (MV) | 1.97 |
| Orbit | |
| Period (P) | 17.9297±0.0039 d |
| Eccentricity (e) | 0.14±0.03 |
| Periastron epoch (T) | 43,051.07±0.83 JD |
|
Argument of periastron (ω) (secondary) |
122±11° |
|
Semi-amplitude (K1) (primary) |
21.5±0.6 km/s |
| Details | |
| Mass | 1.85 M☉ |
| Radius | 10.3 R☉ |
| Luminosity | 10.3 L☉ |
| Surface gravity (log g) | 4.05 cgs |
| Temperature | 7,575 K |
| Metallicity [Fe/H] | 0.04 dex |
| Rotational velocity (v sin i) | 82 km/s |
| Age | 800 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
ζ Eridani (Latinised as Zeta Eridani, abbreviated to ζ Eri or Zeta Eri) also named Zibal, is a star in the constellation of Eridanus. With an apparent visual magnitude of 4.80, it is visible to the naked eye on a clear dark night. The distance to this star, as determined via parallax measurements, is around 110 light years.
This is a single-linedspectroscopic binary system with an orbital period of 17.9 days and an eccentricity of 0.14. The primary is a mild Am star with a stellar classification of kA4hA9mA9V. This notation indicates this is a main-sequence star with the Ca-II K absorption line strength (k) of an A4 star, and the hydrogen lines (h) and metallic lines (m) of an A9 star. It has about 185% of the Sun's mass and 10.3 times the Sun's radius. This is a relatively young star with an estimated age of 800 million years, and it appears to have a moderately high rotation rate with a projected rotational velocity of 82 km/s.
The system displays a statistically significant infrared excess at a wavelength of 70 μm. This suggests the presence of an orbiting debris disk. The temperature of the dust is 70 K, indicating an orbital distance of 31 AU. It has an estimated mass of about 0.26% of the Earth.
ζ Eridani (Latinised to Zeta Eridani) is the star's Bayer designation.
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