Gliese 625
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Draco |
| Right ascension | 16h 25m 24.6233s[1] |
| Declination | 54° 18′ 14.7658″[1] |
| Apparent magnitude (V) | 10.13[2] |
| Characteristics | |
| Spectral type | M1.5V[3] |
| B−V color index | 1.591±0.027[2] |
| Astrometry | |
| Radial velocity (Rv) | −13.01±0.6[4] km/s |
| Proper motion (μ) | RA: 432.073±0.064[1] mas/yr Dec.: −171.668±0.059[1] mas/yr |
| Parallax (π) | 154.3503 ± 0.0161[5] mas |
| Distance | 21.131 ± 0.002 ly (6.4788 ± 0.0007 pc) |
| Absolute magnitude (MV) | 11.06[2] |
| Details | |
| Mass | 0.240±0.013[6] M☉ |
| Radius | 0.255±0.034[6] R☉ |
| Luminosity | 0.01482±0.00022[7] L☉ |
| Surface gravity (log g) | 4.94±0.06[8] cgs |
| Temperature | 3,557±9[4] K |
| Metallicity [Fe/H] | −0.401±0.005[4] dex |
| Rotation | 77.8±5.57 d[8] |
| Rotational velocity (v sin i) | 2.2±0.7[4] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
GJ 625 (AC 54 1646-56) is a small red dwarf star with an exoplanetary companion in the northern constellation of Draco. The system is located at a distance of 21.1 light-years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −13 km/s.[4] It is too faint to be visible to the naked eye, having an apparent visual magnitude of 10.13[2] and an absolute magnitude of 11.06.[2]
This is an M-type main-sequence star with a stellar classification of M1.5V.[3] It is spinning slowly with a rotation period of roughly 78 days, and has a low magnetic activity level.[8] The star has about a quarter of the mass and size of the Sun,[6] and the metal content is 40% the abundances in the Sun's atmosphere. It is radiating just 1.5% of the luminosity of the Sun from its photosphere at an effective temperature of 3,557 K.[4]
Planetary system[]
On May 18, 2017, a planet was detected orbiting AC 54 1646-56 by the HARPS-N telescope.[8] The planet, AC 54 1646-56b or (GJ 625b) orbits on the inner edge of the optimistic circumstellar habitable zone of its star, and may support liquid water. Since the star is considered quiescent (having a low X-ray emission and flare rate), the radio emission from the system may be auroral in nature and coming from a short-period planet. Further observations will be needed to confirm this.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| 2.82±0.51 M
|