Epsilon Reticuli
 Location of ε Reticuli (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Reticulum |
| Right ascension | 4h 16m 29.029s[1] |
| Declination | –59° 18′ 07.76″[1] |
| Apparent magnitude (V) | 4.44[2] / 12.5 |
| Characteristics | |
| Spectral type | K2 IV[3] / D |
| U−B color index | +1.07[2] |
| B−V color index | +1.08[2] |
| Astrometry | |
| Radial velocity (Rv) | +29.3[4] km/s |
| Proper motion (μ) | RA: –47.53 ± 0.17[1] mas/yr Dec.: –167.58 ± 0.17[1] mas/yr |
| Parallax (π) | 54.83 ± 0.15[1] mas |
| Distance | 59.5 ± 0.2 ly (18.24 ± 0.05 pc) |
| Absolute magnitude (MV) | 0.87[5] |
| Details | |
| Surface gravity (log g) | 3.3[6] cgs |
| Temperature | 4,749[6] K |
| Metallicity [Fe/H] | +0.22[6] dex |
| Rotational velocity (v sin i) | 2.80[7] km/s |
| Age | 10[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Reticuli (Epsilon Ret, ε Reticuli, ε Ret) is a double star approximately 59 light-years away in the constellation of Reticulum. The primary component is an orange subgiant, while the secondary is a white dwarf. The two stars share a common motion through space and hence most likely form a binary star system.[3] The brighter star should be easily visible without optical aid under dark skies in the southern hemisphere. In 2000, an extrasolar planet was confirmed to be orbiting the primary star in the system.
Star system
The primary component is a subgiant star with a stellar classification of K2 IV.[3] The fusing of hydrogen in its core is coming to an end and it is in the process of expanding as a red giant. (The NStars project gave it a classification of K2 III, which would make it a giant star.)[9]
The secondary component is a white dwarf star located at a separation of at least 240 AU from the primary.[3] It has a surface temperature between 9000 and 17000 K.
Planetary system
On December 11, 2000, a team of astronomers announced the discovery of a planet Epsilon Reticuli b.[10] With a minimum mass of 1.17 that of Jupiter, the planet moves around Epsilon Reticuli with an average separation of 1.16 AUs. The eccentricity of the planet is extremely low (at 0.06), and it completes an orbit every 418 days (or 1.13 years).
Stability analysis shows that the planet's Lagrangian points would be stable enough to host Earth-sized planets, though as yet no trojan planets have been detected in this system.[11]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >1.56 ± 0.14 MJ | 1.271 ± 0.073 | 428.1 ± 1.1 | 0.060 ± 0.043 | — | — |
References
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Coordinates: 
04h 16m 29.03s, −59° 18′ 07.76″
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