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Upsilon1 Eridani

υ1 Eridanian
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Eridanus
Right ascension 04h 33m 30.55236s
Declination −29° 45′ 59.3725″
Apparent magnitude (V) 4.51
Characteristics
Spectral type K0 III-IV
U−B color index +0.70
B−V color index +0.98
Astrometry
Radial velocity (Rv) +20.89±0.69 km/s
Proper motion (μ) RA: −114.78 mas/yr
Dec.: −271.79 mas/yr
Parallax (π) 25.67 ± 0.24mas
Distance 127 ± 1 ly
(39.0 ± 0.4 pc)
Absolute magnitude (MV) 1.60
Details
Mass 1.54 M
Radius 7.3 R
Luminosity 24 L
Surface gravity (log g) 3.09 cgs
Temperature 4,941 K
Metallicity [Fe/H] −0.16±0.08 dex
Rotational velocity (v sin i) 2.15 km/s
Other designations
υ1 Eridani, υ1 Eri, 50 Eridani, CD−30° 1883, HD 29085, HIP 21248, HR 1453, SAO 169570.
Database references
SIMBAD data

Upsilon1 Eridani (υ1 Eri) is a single star in the constellation Eridanus. It has an apparent visual magnitude is 4.51, 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, is around 127 light years.

This is an evolved red clumpgiant star with a stellar classification of K0III-IV. The measured angular diameter, after correction for limb darkening, is 1.74±0.02 mas. At an estimated distance of this star, this yields a physical size of about 7.3 times the radius of the Sun. It has 154% of the Sun's mass and radiates 24 times the solar luminosity from its outer atmosphere at an effective temperature of 4,941 K.


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