Upsilon2 Eridani
| 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 ± 0.19mas |
| Distance | 214 ± 3 ly (65.6 ± 0.8 pc) |
| 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 |
Upsilon2 Eridani (Upsilon2 Eri, υ2 Eridani, υ2 Eri), also named Theemin, 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 an annual parallax shift of 0.01525″, it is approximately 214 light-years from the Sun.
This is a evolved red clumpgiant star with a stellar classification of G8+ III. The measured angular diameter is 2.21 mas. At an estimated distance of the star, 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.
υ2 Eridani (Latinised to Upsilon2 Eridani) is the star's Bayer designation.
It bore the traditional name Theemin (also written as Theemim and Beemin). In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Theemin for this star on February 1st, 2017 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, 天園 (Tiān Yuán), meaning Celestial Orchard, refers to an asterism consisting of υ2 Eridani, χ Eridani, φ Eridani, κ Eridani, HD 16754, HD 23319, θ Eridani, HD 24072, HD 24160, υ4 Eridani, 43 Eridani and υ1 Eridani. Consequently, υ2 Eridani itself is known as 天園十二 (Tiān Yuán shíèr, English: the Twelfth Star of Celestial Orchard.)
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