Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydra [1] |
Right ascension | 09h 36m 01.63722s [2] |
Declination | −21° 39′ 38.8776″ [2] |
Apparent magnitude (V) | 10.906 [3] |
Characteristics | |
Evolutionary stage | main sequence [4] |
Spectral type | M2.5V [5] |
Astrometry | |
Radial velocity (Rv) | −35.03±0.17 [2] km/s |
Proper motion (μ) | RA: 138.722(23) mas/yr [2] Dec.: −990.342(20) mas/yr [2] |
Parallax (π) | 105.9789±0.0227 mas [2] |
Distance | 30.776 ± 0.007 ly (9.436 ± 0.002 pc) |
Absolute magnitude (MV) | +11.13 [6] |
Details | |
Mass | 0.362 [4] M☉ |
Radius | 0.333 [6] R☉ |
Luminosity | 0.014 [7] L☉ |
Surface gravity (log g) | 4.96 [4] cgs |
Temperature | 3,488 [4] K |
Metallicity [Fe/H] | −0.14 [4] dex |
Rotation | 74.3±1.7 d [8] |
Rotational velocity (v sin i) | 2.5 [4] km/s |
Other designations | |
HIP 47103, TOI-562, 2MASS 09360161-2139371 | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
GJ 357 (Gliese 357) is an M-type main sequence star with an unusually low star spot activity. [9] It is located 31 light-years from the Solar System, [10] in the Hydra constellation. [10]
The star has three confirmed exoplanets in its orbit. [11] One of these, Gliese 357 d, is considered to be a "super-Earth" within the circumstellar habitable zone. [12] [10] [13] [14]
Transiting planets b and c are close to 3:7 mean-motion resonance. Presuming resonance chain extends to the outermost, cold, possibly terrestrial Gliese 357 d and the resonances are simple. Transmission spectroscopy of the planet b with JWST in 2025 found no clear evidence for atmospheric molecules, although a secondary atmosphere is considered likely to exist. [15] Similarly, another 2025 analysis of the JWST transmission spectrum found no atmospheric molecules, but was able to rule out an atmosphere composed mainly of low-molar mass molecules (less than 8 g/mol) and an abundance of metals less than 300 times that of the Sun. [16]
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 | — | — |