82 G. Eridani
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 19m 55.65093s |
| Declination | −43° 04′ 11.2175″ |
| Apparent magnitude (V) | 4.254 |
| Characteristics | |
| Spectral type | G8 V |
| U−B color index | +0.22 |
| B−V color index | +0.71 |
| Astrometry | |
| Radial velocity (Rv) | +87.2 km/s |
| Proper motion (μ) |
RA: 3038.34 mas/yr Dec.: 726.58 mas/yr |
| Parallax (π) | 165.47 ± 0.19mas |
| Distance | 19.71 ± 0.02 ly (6.043 ± 0.007 pc) |
| Absolute magnitude (MV) | 5.34 |
| Details | |
| Mass | 0.70 M☉ |
| Radius | 0.92 R☉ |
| Luminosity | 0.74 L☉ |
| Surface gravity (log g) | 4.40 cgs |
| Temperature | 5,401 K |
| Metallicity [Fe/H] | –0.40 dex |
| Rotational velocity (v sin i) | 4.0 km/s |
| Age | 6.1–12.7 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | The star |
| planet b | |
| planet c | |
| planet d | |
| Exoplanet Archive | data |
| ARICNS | data |
| Extrasolar Planets Encyclopaedia |
data |
82 G. Eridani (HD 20794, HR 1008, e Eridani) is a star about 20 light years away from Earth in the constellation Eridanus. It is a main-sequence star with a stellar classification of G8.
In the southern-sky catalog Uranometria Argentina, 82 G. Eridani (sometimes abbreviated to "82 Eridani") is the 82nd star listed in the constellation Eridanus. The Argentina catalog, compiled by the 19th-century astronomer Benjamin Gould, is a southern celestial hemisphere analog of the more famous Flamsteed catalog, and uses a similar numbering scheme. 82 G. Eridani, like other stars near the Sun, has held on to its Gould designation, even while other more distant stars have not.
This star is slightly smaller and less massive than the Sun, making it marginally dimmer than the Sun in terms of luminosity; about 20% more luminous than Tau Ceti or Alpha Centauri B. The projected equatorial rotation rate (v sin i) is 4.0 km/s, compared to 2 km/s for the Sun.
82 G. Eridani is a high-velocity star—it is moving quickly compared to the average—and hence is probably a member of Population II, generally older stars whose motions take them well outside the plane of the Milky Way. Like many other Population II stars, 82 G. Eridani is somewhat metal-deficient (though much less deficient than many), and is older than the Sun. It has a relatively high orbital eccentricity of 0.40 about the galaxy, ranging between 4.6 and 10.8 kiloparsecs from the core. Estimates of the age of this star ranged from 6 to 12 billion years.
This star is located in a region of low-density interstellar matter (ISM), so it is believed to have a large astropause that subtends an angle of 6″ across the sky. Relative to the Sun, this star is moving at a space velocity of 101 km/s, with the bow shock advancing at more than Mach 3 through the ISM.
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