Gliese 357

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]

Gliese 357
Image showing a red star and three planets. GJ357d is green and covered with life.
Artist concept of the Gliese 357 (GJ357) system.
Credit: Jack Madden
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]
Distance30.776 ± 0.007 ly
(9.436 ± 0.002 pc)
Absolute magnitude (MV)+11.13[4]
Details
Mass0.362[5] M☉
Radius0.333[4] R☉
Luminosity0.014[6] L☉
Surface gravity (log g)4.96[5] cgs
Temperature3,488[5] K
Metallicity [Fe/H]−0.14[5] dex
Rotation74.3±1.7 d[7]
Rotational velocity (v sin i)2.5[5] km/s
Other designations
HIP 47103, 2MASS 09360161-2139371, TOI 562
Database references
SIMBADdata

Planetary system

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.

The Gliese 357 planetary system[14]
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		 — —

References
  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. Koen, C.; Kilkenny, D.; Van Wyk, F.; Marang, F. (2010). "UBV(RI)C JHK observations of Hipparcos-selected nearby stars". Monthly Notices of the Royal Astronomical Society. 403 (4): 1949. Bibcode:2010MNRAS.403.1949K. doi:10.1111/j.1365-2966.2009.16182.x.
  3. Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  4. Houdebine, E. R.; Mullan, D. J.; Paletou, F.; Gebran, M.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2016). "Rotation-Activity Correlations in K and M Dwarfs. I. Stellar Parameters and Compilations of v sin I and P/Sin I for a Large Sample of Late-K and M Dwarfs". The Astrophysical Journal. 822 (2): 97. arXiv:1604.07920. Bibcode:2016ApJ...822...97H. doi:10.3847/0004-637X/822/2/97. S2CID 119118088.
  5. Passegger, V. M.; Reiners, Ansgar; Jeffers, S. V.; Wende-von Berg, S.; Schöfer, P.; Caballero, J. A.; Schweitzer, A.; Amado, P. J.; Béjar, V. J. S.; Cortés-Contreras, M.; Hatzes, A. P.; Kürster, M.; Montes, D.; Pedraz, S.; Quirrenbach, A.; Ribas, I.; Seifert, W. (2018). "The CARMENES search for exoplanets around M dwarfs. Photospheric parameters of target stars from high-resolution spectroscopy". Astronomy and Astrophysics. 615: A6. arXiv:1802.02946. Bibcode:2018A&A...615A...6P. doi:10.1051/0004-6361/201732312. S2CID 55639432.
  6. Morales, J. C.; Ribas, I.; Jordi, C.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2008). "The effect of activity on stellar temperatures and radii". Astronomy and Astrophysics. 478 (2): 507. arXiv:0711.3523. Bibcode:2008A&A...478..507M. doi:10.1051/0004-6361:20078324. S2CID 16238033.
  7. Suárez Mascareño, A.; Rebolo, R.; González Hernández, J. I.; Esposito, M. (2015), "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators", Monthly Notices of the Royal Astronomical Society, 452 (3): 2745–2756, arXiv:1506.08039, Bibcode:2015MNRAS.452.2745S, doi:10.1093/mnras/stv1441
  8. Modirrousta-Galian, D.; Stelzer, B.; Magaudda, E.; Maldonado, J.; Güdel, M.; Sanz-Forcada, J.; Edwards, B.; Micela, G. (2020), "A Super-Earth Orbiting an Extremely Inactive Host Star", Astronomy & Astrophysics, A113: 641, arXiv:2007.10262, doi:10.1051/0004-6361/202038280, S2CID 220647396
  9. Reddy, Francis; Center, NASA’s Goddard Space Flight (2019-07-31). "TESS Discovers Habitable Zone Planet in GJ 357 System". SciTechDaily. Retrieved 2019-08-01.
  10. "The Extrasolar Planet Encyclopaedia — Gj 357 b". exoplanet.eu. Retrieved 2019-08-01.
  11. Falconer, Rebecca, Newly uncovered super-Earth 31 light-years away may be habitable, Axios, August 1, 2019
  12. "Potentially habitable 'super-Earth' discovered just 31 light-years away". NBC News. Retrieved 2019-08-01.
  13. Garner, Rob (2019-07-30). "NASA's TESS Helps Find Intriguing New World". NASA. Retrieved 2019-08-01.
  14. Luque, R.; Pallé, E.; et al. (August 2019). "Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization". Astronomy & Astrophysics. 628: A39. arXiv:1904.12818. Bibcode:2019A&A...628A..39L. doi:10.1051/0004-6361/201935801. S2CID 139102184.
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