{{Short description|Red dwarf with low starspot activity in the Hydra constellation}} {{Starbox begin}} {{Starbox image | image = [[File:GJ 357 system.png|alt=Image showing a red star and three planets. GJ357d is green and covered with life. |300x300px ]] | caption = Artist concept of the Gliese 357 (GJ357) system. | credit = Jack Madden }} {{Starbox observe | epoch=J2000 | constell = [[Hydra (constellation)|Hydra]]<ref>{{cite constellation|GJ 357}}</ref> | ra = {{RA|09|36|01.63722}}<ref name="GaiaDR3"/> | dec = {{DEC|-21|39|38.8776}}<ref name="GaiaDR3"/> | appmag_v = 10.906<ref name=ubv>{{cite journal |bibcode=2010MNRAS.403.1949K |title=UBV(RI)<SUB>C</SUB> JHK observations of Hipparcos-selected nearby stars |journal=Monthly Notices of the Royal Astronomical Society |volume=403 |issue=4 |pages=1949 |last1=Koen |first1=C. |last2=Kilkenny |first2=D. |last3=Van Wyk |first3=F. |last4=Marang |first4=F. |year=2010 |doi=10.1111/j.1365-2966.2009.16182.x |doi-access=free }}</ref> }} {{Starbox character | type = [[main sequence]]<ref name=carmenes/> | class = M2.5V<ref name=nstars>{{cite journal |bibcode=2006AJ....132..161G |title=Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample |journal=The Astronomical Journal |volume=132 |issue=1 |pages=161–170 |last1=Gray |first1=R. O. |last2=Corbally |first2=C. J. |last3=Garrison |first3=R. F. |last4=McFadden |first4=M. T. |last5=Bubar |first5=E. J. |last6=McGahee |first6=C. E. |last7=O'Donoghue |first7=A. A. |last8=Knox |first8=E. R. |year=2006 |arxiv=astro-ph/0603770 |doi=10.1086/504637 |s2cid=119476992 }}</ref> }} {{Starbox astrometry | radial_v = {{val|-35.03|0.17}}<ref name="GaiaDR3"/> | prop_mo_ra = {{val|138.722|(23)}} | prop_mo_dec = {{val|-990.342|(20)}} | pm_footnote = <ref name="GaiaDR3"/> | parallax = 105.9789 | p_error = 0.0227 | parallax_footnote = <ref name="GaiaDR3"/> | absmag_v = +11.13<ref name=houdebine>{{cite journal |bibcode=2016ApJ...822...97H |title=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 |journal=The Astrophysical Journal |volume=822 |issue=2 |pages=97 |last1=Houdebine |first1=E. R. |last2=Mullan |first2=D. J. |last3=Paletou |first3=F. |last4=Gebran |first4=M. |last5=Bubar |first5=E. J. |last6=McGahee |first6=C. E. |last7=O'Donoghue |first7=A. A. |last8=Knox |first8=E. R. |year=2016 |arxiv=1604.07920 |doi=10.3847/0004-637X/822/2/97 |s2cid=119118088 |doi-access=free }}</ref> }} {{Starbox detail | mass = {{Val|0.346|0.007}}<ref name=Weisserman2026/> | radius = {{Val|0.360|0.011}}<ref name=Weisserman2026/> | temperature = 3,488<ref name=carmenes/> | luminosity = 0.014<ref name=morales>{{cite journal |bibcode=2008A&A...478..507M |title=The effect of activity on stellar temperatures and radii |journal=Astronomy and Astrophysics |volume=478 |issue=2 |pages=507 |last1=Morales |first1=J. C. |last2=Ribas |first2=I. |last3=Jordi |first3=C. |last4=McFadden |first4=M. T. |last5=Bubar |first5=E. J. |last6=McGahee |first6=C. E. |last7=O'Donoghue |first7=A. A. |last8=Knox |first8=E. R. |year=2008 |arxiv=0711.3523 |doi=10.1051/0004-6361:20078324 |s2cid=16238033 }}</ref> | gravity = {{Val|4.86|0.03}}<ref name=Weisserman2026/> | rotational_velocity = 2.5<ref name=carmenes>{{cite journal |bibcode=2018A&A...615A...6P |title=The CARMENES search for exoplanets around M dwarfs. Photospheric parameters of target stars from high-resolution spectroscopy |journal=Astronomy and Astrophysics |volume=615 |pages=A6 |last1=Passegger |first1=V. M. |last2=Reiners |first2=Ansgar |last3=Jeffers |first3=S. V. |last4=Wende-von Berg |first4=S. |last5=Schöfer |first5=P. |last6=Caballero |first6=J. A. |last7=Schweitzer |first7=A. |last8=Amado |first8=P. J. |last9=Béjar |first9=V. J. S. |last10=Cortés-Contreras |first10=M. |last11=Hatzes |first11=A. P. |last12=Kürster |first12=M. |last13=Montes |first13=D. |last14=Pedraz |first14=S. |last15=Quirrenbach |first15=A. |last16=Ribas |first16=I. |last17=Seifert |first17=W. |year=2018 |arxiv=1802.02946 |doi=10.1051/0004-6361/201732312 |s2cid=55639432 }}</ref> | metal_fe = {{val|-0.12|0.12}}<ref name=Weisserman2026/> | rotation = {{val|74.3|1.7|ul=d}}<ref>{{cite journal |arxiv=1506.08039 |doi=10.1093/mnras/stv1441 |title=Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators |year=2015 |last1=Suárez Mascareño |first1=A. |last2=Rebolo |first2=R. |last3=González Hernández |first3=J. I. |last4=Esposito |first4=M. |journal=Monthly Notices of the Royal Astronomical Society |volume=452 |issue=3 |pages=2745–2756 |doi-access=free |bibcode=2015MNRAS.452.2745S }}</ref> | age_myr = }} {{Starbox catalog | names= {{odlist |HIP=47103 |2MASS=09360161-2139371 |TOI=562}} }} {{Starbox reference | Simbad = HIP+47103 | NSTED = GJ-357 | ARICNS = 00749 }} {{Starbox end}} '''GJ 357''' ('''Gliese 357''') is an [[M-type main sequence star]] with an unusually low star spot activity.<ref>{{cite journal|arxiv=2007.10262|title=A Super-Earth Orbiting an Extremely Inactive Host Star|year=2020 |doi=10.1051/0004-6361/202038280|last1=Modirrousta-Galian|first1=D.|last2=Stelzer|first2=B.|last3=Magaudda |first3=E.|last4=Maldonado|first4=J.|last5=Güdel|first5=M.|last6=Sanz-Forcada|first6=J.|last7=Edwards|first7=B. |last8=Micela|first8=G.|journal=Astronomy & Astrophysics|volume=A113|page=641|s2cid=220647396}}</ref> It is located 31 light-years from the [[Solar System]],<ref name=":0">{{Cite web|url=https://scitechdaily.com/tess-discovers-habitable-zone-planet-in-gj-357-system/|title=TESS Discovers Habitable Zone Planet in GJ 357 System|last1=Reddy|first1=Francis|last2=Center|first2=NASA’s Goddard Space Flight|date=2019-07-31|website=SciTechDaily|language=en-US|access-date=2019-08-01|archive-date=2019-08-01|archive-url=https://web.archive.org/web/20190801162521/https://scitechdaily.com/tess-discovers-habitable-zone-planet-in-gj-357-system/|url-status=live}}</ref> in the [[Hydra (constellation)|Hydra constellation]].<ref name=":0" />
==Planetary system== The star has three confirmed [[exoplanets]] in its orbit. <ref>{{Cite encyclopedia|url=https://exoplanet.eu/catalog/gj_357_b--7109/|title=The Extrasolar Planet Encyclopaedia — Gj 357 b|date=1995|encyclopedia=[[Extrasolar Planets Encyclopaedia]]|access-date=2019-08-01|archive-date=2023-11-07|archive-url=https://web.archive.org/web/20231107150843/https://exoplanet.eu/catalog/gj_357_b--7109/|url-status=live}}</ref> One of these, [[Gliese 357 d]], is considered to be a "[[super-Earth]]" within the [[circumstellar habitable zone]].<ref>Falconer, Rebecca, ''[https://www.axios.com/super-earth-31-light-years-away-may-support-life-d1d0298d-3c82-4f99-a4af-22774fc1ed70.html Newly uncovered super-Earth 31 light-years away may be habitable] {{Webarchive|url=https://web.archive.org/web/20191218061126/https://www.axios.com/super-earth-31-light-years-away-may-support-life-d1d0298d-3c82-4f99-a4af-22774fc1ed70.html |date=2019-12-18 }}'', Axios, August 1, 2019</ref><ref name=":0" /><ref>{{Cite web|url=https://www.nbcnews.com/mach/science/potentially-habitable-super-earth-discovered-just-31-light-years-away-ncna1037491|title=Potentially habitable 'super-Earth' discovered just 31 light-years away|website=NBC News|date=31 July 2019|language=en|access-date=2019-08-01|archive-date=2019-07-31|archive-url=https://web.archive.org/web/20190731230808/https://www.nbcnews.com/mach/science/potentially-habitable-super-earth-discovered-just-31-light-years-away-ncna1037491|url-status=live}}</ref><ref>{{Cite web|url=http://www.nasa.gov/feature/goddard/2019/confirmation-of-toasty-tess-planet-leads-to-surprising-find-of-promising-world|title=NASA's TESS Helps Find Intriguing New World|last=Garner|first=Rob|date=2019-07-30|website=NASA|access-date=2019-08-01|archive-date=2019-08-01|archive-url=https://web.archive.org/web/20190801045621/https://www.nasa.gov/feature/goddard/2019/confirmation-of-toasty-tess-planet-leads-to-surprising-find-of-promising-world/|url-status=live}}</ref>
Transmission spectroscopy of the planet b with [[James Webb Space Telescope|JWST]] in 2025 found no clear evidence for atmospheric molecules, although a secondary atmosphere is considered likely to exist.<ref>{{cite journal |arxiv=2505.24462 |last1=Taylor |first1=Jake |last2=Radica |first2=Michael |last3=Chatterjee |first3=Richard D. |last4=Hammond |first4=Mark |last5=Meier |first5=Tobias |last6=Aigrain |first6=Suzanne |last7=MacDonald |first7=Ryan J. |last8=Albert |first8=Loic |last9=Benneke |first9=Björn |last10=Coulombe |first10=Louis-Philippe |last11=Cowan |first11=Nicolas B. |last12=Dang |first12=Lisa |last13=Doyon |first13=René |last14=Flagg |first14=Laura |last15=Johnstone |first15=Doug |last16=Kaltenegger |first16=Lisa |last17=Lafrenière |first17=David |last18=Pelletier |first18=Stefan |last19=Piaulet-Ghorayeb |first19=Caroline |last20=Rowe |first20=Jason F. |last21=Roy |first21=Pierre-Alexis |title=JWST NIRISS Transmission Spectroscopy of the Super-Earth GJ 357b, a Favourable Target for Atmospheric Retention |journal=Monthly Notices of the Royal Astronomical Society |date=2025 |volume=540 |issue=4 |page=3677 |doi=10.1093/mnras/staf894 |doi-access=free |bibcode=2025MNRAS.540.3677T }}</ref> 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 [[metallicity|metals]] less than 300 times that of the Sun.<ref name=Redai2025>{{Cite journal |last1=Redai |first1=Jea Adams |last2=Wogan |first2=Nicholas |last3=Wallack |first3=Nicole L. |last4=Alam |first4=Munazza K. |last5=Aguichine |first5=Artyom |last6=Wolfgang |first6=Angie |last7=Wakeford |first7=Hannah R. |last8=Teske |first8=Johanna |last9=Scarsdale |first9=Nicholas |title=JWST COMPASS: A NIRSpec G395H Transmission Spectrum of the Super-Earth GJ 357 b |journal=The Astronomical Journal |date=2025-07-09 |volume=170 |issue=4 |page=219 |doi=10.3847/1538-3881/adee92 |doi-access=free |arxiv=2507.07165 |bibcode=2025AJ....170..219A }}</ref>
{{OrbitboxPlanet begin | table_ref = <ref name="Luque2019"/> }} {{OrbitboxPlanet | exoplanet = b | mass_earth = {{val|1.83|0.30}}<ref name=Weisserman2026/> | radius_earth = {{val|1.21|0.05}}<ref name=Weisserman2026/> | semimajor = {{val|0.035|0.002}} | period = {{val|3.93072|0.00008|0.00006}} | eccentricity = 0.047{{±|0.059|0.047|}} | inclination = {{val|89.12|0.37|0.31}} }} {{OrbitboxPlanet | exoplanet = c | mass_earth = {{val|3.40|0.46|p=≥}} | radius_earth = | semimajor = {{val|0.061|0.004}} | period = {{val|9.1247|0.0011|0.0010}} | eccentricity = 0.072{{±|0.053|}} | inclination = }} {{OrbitboxPlanet | exoplanet = [[Gliese 357 d|d]] | mass_earth = {{val|6.1|1.0|p=≥}} | radius_earth = | semimajor = {{val|0.204|0.015}} | period = {{val|55.661|0.055}} | eccentricity = 0.033{{±|0.057|0.033|}} | inclination = }} {{Orbitbox end}}
== References == <references> <ref name="GaiaDR3">{{Cite Gaia DR3|5664814198431308288}}</ref>
<ref name="Luque2019">{{cite journal |last1=Luque |first1=R. |last2=Pallé |first2=E. |display-authors=etal |date=August 2019 |title=Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization |journal=[[Astronomy & Astrophysics]] |volume=628 |issue= |pages=A39 |doi=10.1051/0004-6361/201935801 |arxiv=1904.12818 |bibcode=2019A&A...628A..39L|s2cid=139102184 }}</ref>
<ref name=Weisserman2026>{{cite journal |last=Weisserman |first=Drew |last2=Gromek |first2=Nicole |last3=Cloutier |first3=Ryan |last4=Bali |first4=Komal |last5=Cadieux |first5=Charles |last6=Plotnykov |first6=Mykhaylo |last7=L'Heureux |first7=Alexandrine |last8=Srivastava |first8=Avidaan |last9=Carmona |first9=Andres |title=Super-Earth masses and stellar abundances from NIRPS reveal tentative evidence for water-rich formation around M dwarfs |date=2026-04-08 |arxiv=2604.07447 |journal=Astronomy & Astrophysics }}</ref> </references> {{Stars of Hydra}}
[[Category:Planetary systems with three confirmed planets]] [[Category:M-type main-sequence stars]] [[Category:Gliese and GJ objects|0357]] [[Category:Hydra (constellation)]] [[Category:Hipparcos objects|047103]] [[Category:TESS Objects of Interest|562]]