Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydra |
Right ascension | 09h 36m 01.63722s [1] |
Declination | −21° 39′ 38.8776″ [1] |
Apparent magnitude (V) | 10.906 [2] |
Characteristics | |
Evolutionary stage | main sequence |
Spectral type | M2.5V [3] |
Astrometry | |
Radial velocity (Rv) | −35.03±0.17 [1] km/s |
Proper motion (μ) |
RA: 138.722±0.023
mas/
yr
[1] Dec.: −990.342±0.020 mas/ yr [1] |
Parallax (π) | 105.9789 ± 0.0227 mas [1] |
Distance | 30.776 ± 0.007
ly (9.436 ± 0.002 pc) |
Absolute magnitude (MV) | +11.13 [4] |
Details | |
Mass | 0.362 [5] M☉ |
Radius | 0.333 [4] R☉ |
Luminosity | 0.014 [6] L☉ |
Surface gravity (log g) | 4.96 [5] cgs |
Temperature | 3,488 [5] K |
Metallicity [Fe/H] | −0.14 [5] dex |
Rotation | 74.3±1.7 d [7] |
Rotational velocity (v sin i) | 2.5 [5] km/s |
Other designations | |
Database references | |
SIMBAD | data |
GJ 357 (also designated Gliese 357) is an M-type main sequence star with an unusually low starspot activity. [8] It is located 31 light-years from the Solar System. [9] The system is part of the Hydra constellation. [9]
The star has three confirmed exoplanets in its orbit, [10] one of which, Gliese 357 d, is considered to be a " super-Earth" within the circumstellar habitable zone. [11] [9] [12] [13]
Planets b and c are close to 3:7 mean-motion resonance. Presuming resonance chain crosses gap to outermost and cold super-terrestrial d and the resonances are simple, GJ 357 may have much more suitable planet for life at approx. 27.5 day period and almost Earth's flux, and (less likely) Mars-sized planet in 2:1 period ratio with GJ 357 c and 2:3 ratio with hypothetical HZ rocky one.[ citation needed]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 1.84±0.31 M🜨 | 0.035±0.002 | 3.93072+0.00008 −0.00006 |
0.047+0.059 −0.047 |
89.12+0.37 −0.31 ° |
1.217+0.084 −0.083 R🜨 |
c | ≥3.40±0.46 M🜨 | 0.061±0.004 | 9.1247+0.0011 −0.0010 |
0.072±0.053 | — | — |
d | ≥6.1±1.0 M🜨 | 0.204±0.015 | 55.661±0.055 | 0.033+0.057 −0.033 |
— | — |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydra |
Right ascension | 09h 36m 01.63722s [1] |
Declination | −21° 39′ 38.8776″ [1] |
Apparent magnitude (V) | 10.906 [2] |
Characteristics | |
Evolutionary stage | main sequence |
Spectral type | M2.5V [3] |
Astrometry | |
Radial velocity (Rv) | −35.03±0.17 [1] km/s |
Proper motion (μ) |
RA: 138.722±0.023
mas/
yr
[1] Dec.: −990.342±0.020 mas/ yr [1] |
Parallax (π) | 105.9789 ± 0.0227 mas [1] |
Distance | 30.776 ± 0.007
ly (9.436 ± 0.002 pc) |
Absolute magnitude (MV) | +11.13 [4] |
Details | |
Mass | 0.362 [5] M☉ |
Radius | 0.333 [4] R☉ |
Luminosity | 0.014 [6] L☉ |
Surface gravity (log g) | 4.96 [5] cgs |
Temperature | 3,488 [5] K |
Metallicity [Fe/H] | −0.14 [5] dex |
Rotation | 74.3±1.7 d [7] |
Rotational velocity (v sin i) | 2.5 [5] km/s |
Other designations | |
Database references | |
SIMBAD | data |
GJ 357 (also designated Gliese 357) is an M-type main sequence star with an unusually low starspot activity. [8] It is located 31 light-years from the Solar System. [9] The system is part of the Hydra constellation. [9]
The star has three confirmed exoplanets in its orbit, [10] one of which, Gliese 357 d, is considered to be a " super-Earth" within the circumstellar habitable zone. [11] [9] [12] [13]
Planets b and c are close to 3:7 mean-motion resonance. Presuming resonance chain crosses gap to outermost and cold super-terrestrial d and the resonances are simple, GJ 357 may have much more suitable planet for life at approx. 27.5 day period and almost Earth's flux, and (less likely) Mars-sized planet in 2:1 period ratio with GJ 357 c and 2:3 ratio with hypothetical HZ rocky one.[ citation needed]
Companion (in order from star) |
Mass |
Semimajor axis ( AU) |
Orbital period ( days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 1.84±0.31 M🜨 | 0.035±0.002 | 3.93072+0.00008 −0.00006 |
0.047+0.059 −0.047 |
89.12+0.37 −0.31 ° |
1.217+0.084 −0.083 R🜨 |
c | ≥3.40±0.46 M🜨 | 0.061±0.004 | 9.1247+0.0011 −0.0010 |
0.072±0.053 | — | — |
d | ≥6.1±1.0 M🜨 | 0.204±0.015 | 55.661±0.055 | 0.033+0.057 −0.033 |
— | — |