Epsilon Columbae
Star in the constellation Columba
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Epsilon Columbae, Latinized from ε Columbae, is a star in the southern constellation of Columba. It is visible to the naked eye, having an apparent visual magnitude of 3.87.[2] Based upon an annual parallax shift of 12.46 mas,[1] it is located approximately 262 light years distant from the Sun. The star is drifting closer with a radial velocity of −5 km/s.[5]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Columba |
| Right ascension | 05h 31m 12.74899s[1] |
| Declination | −35° 28′ 13.8605″[1] |
| Apparent magnitude (V) | 3.87[2] |
| Characteristics | |
| Spectral type | K1 II/III[3] or K1 IIIa[4] |
| U−B color index | +1.08[2] |
| B−V color index | +1.14[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.9[5] km/s |
| Proper motion (μ) | RA: +26.421[1] mas/yr Dec.: −30.085[1] mas/yr |
| Parallax (π) | 12.4610±0.2423 mas[1] |
| Distance | 262 ± 5 ly (80 ± 2 pc) |
| Absolute magnitude (MV) | −0.67[6] |
| Details | |
| Mass | 2.47[7] M☉ |
| Radius | 25.2+3.1 −2.0[1] R☉ |
| Luminosity | 251.2±5.6[1] L☉ |
| Surface gravity (log g) | 2.05[4] cgs |
| Temperature | 4,575+195 −260[1] K |
| Metallicity [Fe/H] | −0.03[4] dex |
| Age | 1.53[7] Gyr |
| Other designations | |
| ε Col, CD−35°2348, FK5 2413, HD 36597, HIP 25859, HR 1862, SAO 195924[8] | |
| Database references | |
| SIMBAD | data |
This is an orange-hued[9] K-type giant star with a stellar classification of K1 II/III.[3] At the age of 1.5[7] billion years old, it has exhausted the supply of hydrogen at its core then cooled and expanded off the main sequence. Epsilon Columbae has 2.5[7] times the mass and 25[1] times the radius of the Sun. The star radiates 251 times the solar luminosity from its enlarged photosphere at an effective temperature of 4,575 K.[1] It has a peculiar velocity of 30.0±3.9 km/s, making it a candidate runaway star system.[10] Based upon changes in the star's movement, it has an orbiting stellar companion of unknown type.[11]