Epsilon Tauri
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| Observation data Epoch J2000.0 |
|
|---|---|
| Constellation (pronunciation) |
Taurus |
| Right ascension | 04h 28m 37.0s |
| Declination | +19° 10' 49" |
| Apparent magnitude (V) | +3.53 |
| Distance | 155 ± 6 ly (48 ± 2 pc) |
| Spectral type | K0III |
| Other designations | |
Epsilon Tauri (ε Tau / ε Tauri) is a star in the constellation Taurus and a member of the Hyades open cluster. It has the traditional names Ain (Arabic عين), or Oculus Borealis, both of which mean "eye". Another traditional name is Coronis (Greek Κορωνις), referring to one of the mythological Hyades sisters.[1]
ε Tau belongs to the spectral class K0 and has apparent magnitude +3.6. It is 155 light years away from the Sun, has a luminosity of 90 times that of the Sun and a radius of 13 times solar. The surface temperature of this star is measured at 4925 kelvins. It has an 11th magnitude companion 182 arcseconds from the primary.
Since ε Tau lies near the plane of the ecliptic, it is sometimes occulted by the Moon and (very rarely) by planets.
[edit] The planet
In 2007 a massive extrasolar planet was reported orbiting the star. The planet orbits ε Tauri every 1.6 years in a somewhat eccentric orbit. At the time of the discovery it was the only known planet in an open cluster.[2][3]
| Planet (in order from star) |
Mass (MJ) |
Orbital period (days) |
Semimajor axis (AU) |
Eccentricity |
|---|---|---|---|---|
| b | >7.6 (± 0.2) | 594.9 (± 5.3) | 1.93 (± 0.03) | 0.151 (± 0.023) |
[edit] References
- ^ Hyginus; translation Mary Grant. Astronomica Part 2, II.21 BULL. Retrieved on 2007-07-05.
- ^ HD 28305 -- Star in double system. SIMBAD Astronomical Database. Retrieved on 2007-01-25.
- ^ Notes for star eps Tau. The Extrasolar Planets Encyclopaedia. Retrieved on 2007-02-09.
