Upsilon2 Eridani
Upsilon2 Eridani (υ² Eridani, abbreviated Upsilon2 Eri, υ2 Eri), officially named Theemin /ˈθiːmən/, is a star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.8. Based upon parallax measurements obtained during the Hipparcos mission, it is approximately 66 parsecs (214 light-years) from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 35m 33.03834s |
| Declination | −30° 33′ 44.4297″ |
| Apparent magnitude (V) | 3.804 |
| Characteristics | |
| Spectral type | G8+ III |
| U−B color index | +0.740 |
| B−V color index | +0.968 |
| Astrometry | |
| Radial velocity (Rv) | −4.0±0.9 km/s |
| Proper motion (μ) | RA: −49.27 mas/yr Dec.: −12.72 mas/yr |
| Parallax (π) | 15.25 ± 0.19 mas |
| Distance | 214 ± 3 ly (65.6 ± 0.8 pc) |
| Absolute magnitude (MV) | −0.27 |
| Details | |
| Radius | 16 R☉ |
| Luminosity | 138 L☉ |
| Surface gravity (log g) | 2.77±0.07 cgs |
| Temperature | 5,074±30 K |
| Metallicity [Fe/H] | 0.04±0.03 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved red clump giant star with a stellar classification of G8+ III. The measured angular diameter is 2.21 mas. At the star's distance, this yields a physical size of around 16 times the radius of the Sun. It radiates 138 times the solar luminosity from its outer atmosphere at an effective temperature of 5074 K.
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