| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 37m 37.4553s |
| Declination | −02° 29′ 28.951″ |
| Apparent magnitude (V) | +10.59 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | M1.1V |
| Astrometry | |
| Radial velocity (Rv) | +20.03+0.10 −0.09 km/s |
| Proper motion (μ) | RA: +54 mas/yr Dec.: –47 mas/yr |
| Parallax (π) | 36.0085±0.4758 mas |
| Distance | 91 ± 1 ly (27.8 ± 0.4 pc) |
| Orbit | |
| Period (P) | 29.39+0.53 −0.44 yr |
| Semi-major axis (a) | 0.335+0.004 −0.003" (9.30+0.24 −0.21 au) |
| Eccentricity (e) | 0.19±0.01 |
| Inclination (i) | 92.17+0.10 −0.12° |
| Longitude of the node (Ω) | 18.88±0.10° |
| Periastron epoch (T) | 2036.67±0.14 |
| Argument of periastron (ω) (secondary) | −66.2+2.5 −2.3° |
| Semi-amplitude (K1) (primary) | 4.01±0.38 km/s |
| Details | |
| GJ 3305 A | |
| Mass | 0.52±0.02 M☉ |
| Luminosity | 0.112±0.007 L☉ |
| Surface gravity (log g) | 4.5 cgs |
| Temperature | 3,500 K |
| Age | 20–30 Myr |
| GJ 3305 B | |
| Mass | 0.44±0.05 M☉ |
| Luminosity | 0.043±0.005 L☉ |
| Surface gravity (log g) | 4.5 cgs |
| Temperature | 3,500 K |
| Age | 20–30 Myr |
| Other designations | |
| GJ 3305, WDS J04376-0228C, 2MASS J04373746-0229282 | |
| Database references | |
| SIMBAD | data |
GJ 3305 is a binary star system in the constellation of Eridanus, notable for being bound to 51 Eridani, an exoplanet-hosting F-type main-sequence star. Based on parallax measurements, it is located at a distance of 91 light-years (28 parsecs).
The two components of GJ 3305 are red dwarfs with a combined spectral type of M1.1V. They orbit around each other with a period of 29.4 years, following a slightly eccentric orbit with e = 0.19 and a semi-major axis of 9.3 au. The orbit is seen nearly edge-on, with an inclination of 92.1°. The primary, GJ 3305 A, has a mass of 0.52±0.02 M☉, while the secondary, GJ 3305 B, has a mass of 0.44±0.05 M☉. Both components are young, estimated to be between 20 and 30 million years old.
GJ 3305 was first noted as a physical companion to 51 Eridani in 2006. The two systems are separated by 66", yielding a projected separation of ~2,000 au.