Gliese 357

Gliese 357
Image showing a red star and three planets. GJ357d is green and covered with life.
Artist concept of the GJ 357 system.
Credit: Jack Madden
Observation data
Epoch J2000      Equinox ICRS
Constellation Hydra
Right ascension 09h 36m 01.63722s
Declination −21° 39′ 38.8776″
Apparent magnitude (V) 10.906
Characteristics
Evolutionary stage Main sequence
Spectral type M2.5V
Astrometry
Radial velocity (Rv)−35.03±0.17 km/s
Proper motion (μ) RA: 138.722(23) mas/yr
Dec.: −990.342(20) mas/yr
Parallax (π)105.9789±0.0227 mas
Distance30.776 ± 0.007 ly
(9.436 ± 0.002 pc)
Absolute magnitude (MV)+11.13
Details
Mass0.3455+0.0078
−0.0077 M☉
Radius0.3382+0.0093
−0.0087 R☉
Luminosity0.01621+0.00056
−0.00055 L☉
Surface gravity (log g)4.918+0.024
−0.025 cgs
Temperature3,540±51 K
Metallicity [Fe/H]−0.50+0.22
−0.21 dex
Rotation74.3±1.7 d
Rotational velocity (v sin i)2.5 km/s
Other designations
HIP 47103, TOI-562, 2MASS 09360161-2139371
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

GJ 357 (Gliese 357) is a red dwarf star with an unusually low starspot activity. It is located 31 light-years from Earth, in the constellation Hydra.

Planetary system

The star has three confirmed exoplanets in its orbit. One of these, GJ 357 d, is considered to be a super-Earth within the circumstellar habitable zone.

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. 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. A 2026 study found dayside temperature of 923+39
−38 K (649.9 ± 39.0 °C; 1,201.7 ± 70.2 °F) for the planet, which is considered anomalously high compared to previous predictions. The data is inconsistent with the predictions for an airless rock with an albedo of zero, and with several atmospheric compositions with high mean molar mass. Hot spots, untested atmospheric conditions, and wavelength-dependent surface emissivity could explain the anomalously high temperature.

The Gliese 357 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination
(°)		 Radius
b 2.05±0.43 M🜨 0.03420+0.00025
−0.00026		 3.93060494+0.00000062
−0.00000058		 0.047+0.032
−0.030		 89.11+0.33
−0.22		 1.152+0.034
−0.032 R🜨
c ≥3.51±0.57 M🜨 0.061±0.004 9.1253+0.0015
−0.0013		 0.115+0.120
−0.081		 — —
d ≥6.7±1.1 M🜨 0.2001±0.0015 55.606+0.062
−0.053		 0.18+0.17
−0.12		 — —

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 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.
  3. ↑ 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. hdl:10566/813.
  4. 1 2 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.
  5. ↑ 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.
  6. ↑ 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.
  7. 1 2 3 Zgraggen, Merlin; Demory, Brice-Olivier; Diamond-Lowe, Hannah; Mendonça, João M.; Valdés, Erik Meier; Fortune, Mark; Jones, Kathryn D.; Kitzmann, Daniel; Smith, Millie; Allen, Natalie H.; August, Prune C.; Gressier, Amélie; Holmberg, Måns; Ih, Jegug; Buchhave, Lars A.; Espinoza, Néstor; Gibson, Neale P.; Heng, Kevin (2026). "Hot Rocks Survey VI: An anomalously hot dayside for the rocky planet GJ 357 b". arXiv:2609.30552 [astro-ph.EP].
  8. ↑ 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.
  9. ↑ 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.
  10. 1 2 3 Reddy, Francis; Center, NASA’s Goddard Space Flight (2019-07-31). "TESS Discovers Habitable Zone Planet in GJ 357 System". SciTechDaily. Archived from the original on 2019-08-01. Retrieved 2019-08-01.
  11. ↑ "The Extrasolar Planet Encyclopaedia — Gj 357 b". Extrasolar Planets Encyclopaedia. 1995. Archived from the original on 2023-11-07. Retrieved 2019-08-01.
  12. ↑ Falconer, Rebecca, Newly uncovered super-Earth 31 light-years away may be habitable Archived 2019-12-18 at the Wayback Machine, Axios, August 1, 2019
  13. ↑ "Potentially habitable 'super-Earth' discovered just 31 light-years away". NBC News. 31 July 2019. Archived from the original on 2019-07-31. Retrieved 2019-08-01.
  14. ↑ Garner, Rob (2019-07-30). "NASA's TESS Helps Find Intriguing New World". NASA. Archived from the original on 2019-08-01. Retrieved 2019-08-01.
  15. ↑ Taylor, Jake; Radica, Michael; Chatterjee, Richard D.; Hammond, Mark; Meier, Tobias; Aigrain, Suzanne; MacDonald, Ryan J.; Albert, Loic; Benneke, Björn; Coulombe, Louis-Philippe; Cowan, Nicolas B.; Dang, Lisa; Doyon, René; Flagg, Laura; Johnstone, Doug; Kaltenegger, Lisa; Lafrenière, David; Pelletier, Stefan; Piaulet-Ghorayeb, Caroline; Rowe, Jason F.; Roy, Pierre-Alexis (2025). "JWST NIRISS Transmission Spectroscopy of the Super-Earth GJ 357b, a Favourable Target for Atmospheric Retention". Monthly Notices of the Royal Astronomical Society. 540 (4): 3677. arXiv:2505.24462. Bibcode:2025MNRAS.540.3677T. doi:10.1093/mnras/staf894.
  16. ↑ Redai, Jea Adams; Wogan, Nicholas; Wallack, Nicole L.; Alam, Munazza K.; Aguichine, Artyom; Wolfgang, Angie; Wakeford, Hannah R.; Teske, Johanna; Scarsdale, Nicholas (2025-07-09). "JWST COMPASS: A NIRSpec G395H Transmission Spectrum of the Super-Earth GJ 357 b". The Astronomical Journal. 170 (4): 219. arXiv:2507.07165. Bibcode:2025AJ....170..219A. doi:10.3847/1538-3881/adee92.