Upsilon1 Eridani
Red clump star in the constellation Eridanus
From Wikipedia, the free encyclopedia
Upsilon1 Eridani (υ1 Eri) is a single star in the constellation Eridanus. It has an apparent visual magnitude is 4.51,[2] which is bright enough to be faintly visible to the naked eye on a clear, dark night. The distance to this star, as determined using the parallax method,[1] is around 127 light years.
 | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 33m 30.55236s[1] |
| Declination | −29° 45′ 59.3725″[1] |
| Apparent magnitude (V) | 4.51[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0 III-IV[4] |
| U−B color index | +0.70[2] |
| B−V color index | +0.98[2] |
| Astrometry | |
| Radial velocity (Rv) | +20.89±0.69[5] km/s |
| Proper motion (μ) | RA: −114.78[1] mas/yr Dec.: −271.79[1] mas/yr |
| Parallax (π) | 25.67±0.24 mas[1] |
| Distance | 127 ± 1 ly (39.0 ± 0.4 pc) |
| Absolute magnitude (MV) | 1.60[5] |
| Details | |
| Mass | 1.54[5] M☉ |
| Radius | 7.3[6] R☉ |
| Luminosity | 24[5] L☉ |
| Surface gravity (log g) | 3.09[5] cgs |
| Temperature | 4,941[5] K |
| Metallicity [Fe/H] | −0.16±0.08[5] dex |
| Rotational velocity (v sin i) | 2.15[7] km/s |
| Other designations | |
| υ1 Eridani, υ1 Eri, 50 Eridani, CD−30°1883, HD 29085, HIP 21248, HR 1453, SAO 169570[8] | |
| Database references | |
| SIMBAD | data |
This is an evolved red clump[3] giant star with a stellar classification of K0III-IV.[4] The measured angular diameter, after correction for limb darkening, is 1.74±0.02 mas.[9] At an estimated distance of this star, this yields a physical size of about 7.3 times the radius of the Sun.[6] It has 154%[5] of the Sun's mass and radiates 24 times the solar luminosity from its outer atmosphere at an effective temperature of 4,941 K.[5]
