GJ 1289
Red dwarf
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GJ 1289 is a red dwarf star located approximately 27 light-years from the Sun in the constellation Andromeda. It is a single star of spectral class M4.5 V, with about 21% of the Sun's mass. The star hosts at least one confirmed exoplanet, GJ 1289 b, and is fully convective, making it a target for studying planetary formation around low-mass stars.[6] Despite its slow rotation, GJ 1289 exhibits large-scale magnetic field strengths similar to those of faster-rotating M dwarfs, suggesting that the star operates a dynamo process in a regime distinct from more rapidly rotating stars.[9][4] The star is predominantly poloidal with its magnetic topology varying over time, and their small-scale fields contribute more than 70% of the star's overall magnetic flux.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥6.27+1.23 −1.25 M🜨 |
0.27±0.01 | 111.74+0.73 −0.71 |
0 | — | — |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda[1] |
| Right ascension | 23h 43m 06.31184s[2] |
| Declination | +36° 32′ 13.1373″[2] |
| Apparent magnitude (V) | 12.67[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | M4.5Ve[3] |
| Astrometry | |
| Radial velocity (Rv) | −3.85±0.41[2] km/s |
| Proper motion (μ) | RA: +941.841 mas/yr[2] Dec.: −151.272 mas/yr[2] |
| Parallax (π) | 119.5794±0.0563 mas[2] |
| Distance | 27.28 ± 0.01 ly (8.363 ± 0.004 pc) |
| Details | |
| Mass | 0.21±0.02[4] M☉ |
| Radius | 0.233±0.005[4] R☉ |
| Luminosity | 0.0054[5] L☉ |
| Surface gravity (log g) | 5.06±0.05[4] cgs |
| Temperature | 3296±30[4] K |
| Metallicity [Fe/H] | 0.02±0.10[4] dex |
| Rotation | 73.66±0.92 d[6] |
| Rotational velocity (v sin i) | 2.0[7] km/s |
| Age | 2.6[8] Gyr |
| Other designations | |
| GJ 1289, G 130-4, LHS 4003, NLTT 57748, TYC 2779-1797-1[3] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
