{{Short description|Red dwarf star in the constellation Pictor}} {{Starbox begin}} {{Starbox observe | epoch = J2000 | constell = Pictor<ref>{{cite web |url=http://djm.cc/constellation.html |title=Finding the constellation which contains given sky coordinates |date=2 August 2008 |website=djm.cc}}</ref> | ra = {{RA|04|33|39.72001}}<ref name="GaiaDR3"/> | dec = {{DEC|-51|57|22.4354}}<ref name="GaiaDR3"/> | appmag_v = 12.617<ref name="SIMBAD"/> }} {{Starbox character | type = Main sequence<ref name="VanEylen2021"/> | class = M3.0V<ref name="Günther2019"/> | appmag_1_passband = V | appmag_1 = {{val|12.617|0.03}}<ref name="SIMBAD"/> | appmag_2_passband = R | appmag_2 = {{val|12.147|0.05}}<ref name="SIMBAD"/> | appmag_3_passband = G | appmag_3 = {{val|11.621|0.003}}<ref name="GaiaDR3"/> | appmag_4_passband = J | appmag_4 = {{val|9.099|0.032}}<ref name="SIMBAD"/> | appmag_5_passband = H | appmag_5 = {{val|8.531|0.073}}<ref name="SIMBAD"/> | appmag_6_passband = K | appmag_6 = {{val|8.251|0.029}}<ref name="SIMBAD"/> }} {{Starbox astrometry | radial_v = {{val|25.90|0.37}}<ref name="GaiaDR3"/> | prop_mo_ra = +83.082 | prop_mo_dec = −269.803 | pm_footnote = <ref name="GaiaDR3"/> | parallax = 44.4899 | p_error = 0.0147 | parallax_footnote = <ref name="GaiaDR3"/> | absmag_v = | absmag_bol = }} {{Starbox detail | source = <ref name="VanEylen2021"/> | mass = {{val|0.386|0.008}} | radius = {{val|0.378|0.011}} | luminosity_bolometric = {{val|0.0194|0.0019}} | gravity = {{val|4.872|0.026}} | temperature = {{val|3506|70}} | metal_fe = {{val|-0.20|0.12}} | rotation = | rotational_velocity = | age_gyr = }} {{Starbox catalog | names = {{odlist | 2MASS = J04333970-5157222 | L = 231-32 | PM = J04336-5157 | TIC = 259377017 | TOI = 270}}<ref name="SIMBAD"/> }} {{Starbox reference | Simbad = TOI-270 | NSTED = TOI-270 }} {{Starbox end}}
'''TOI-270''', also known as '''L 231-32''', is a red dwarf star {{convert|73.3|ly|pc|lk=on|abbr=off}} away in the constellation Pictor. It has about 39% the mass and 38% the radius of the Sun, and a temperature of about {{convert|3506|K|C F|lk=on}}. TOI-270 hosts a system of three known exoplanets.
==Planetary system== The three planets of TOI-270 were discovered in 2019 by the transit method with TESS.<ref name="Günther2019"/> Their masses have since been measured by both Doppler spectroscopy<ref name="VanEylen2021"/> and transit-timing variations.<ref name="Kaye2022"/> The innermost planet, TOI-270 b, is a volatile-rich super-Earth,<ref name="Coulombe2025" /> while the two outer planets are mini-Neptunes.<ref name="VanEylen2021"/> TOI-270 b and c orbit near a 5:3 resonance, while TOI-270 c and d orbit near a 2:1 resonance.<ref name="Günther2019"/>
Observations of the outermost planet, TOI-270 d, by the Hubble Space Telescope suggest a hydrogen-rich atmosphere with signs of water vapor.<ref name="Mikal-Evans2023"/> TOI-270 c & d are good targets for atmospheric detection with the James Webb Space Telescope (JWST).<ref name="Chouqar2020"/>
It was found that TOI-270 b possibly has an atmosphere rich in water vapor based on the revised density value and JWST transmission spectroscopy result.<ref name="Coulombe2025">{{cite journal |last1=Coulombe |first1=Louis-Philippe |last2=Benneke |first2=Björn |last3=Krissansen-Totton |first3=Joshua |last4=l'Heureux |first4=Alexandrine |last5=Piaulet-Ghorayeb |first5=Caroline |last6=Radica |first6=Michael |last7=Roy |first7=Pierre-Alexis |last8=Ahrer |first8=Eva-Maria |last9=Cadieux |first9=Charles |last10=Miguel |first10=Yamila |last11=Schlichting |first11=Hilke E. |last12=Delgado-Mena |first12=Elisa |last13=Monaghan |first13=Christopher |last14=Adamski |first14=Hanna |last15=Raul |first15=Eshan |last16=Cloutier |first16=Ryan |last17=Komacek |first17=Thaddeus D. |last18=Taylor |first18=Jake |last19=Gapp |first19=Cyril |last20=Allart |first20=Romain |last21=Bouchy |first21=François |last22=Canto Martins |first22=Bruno L. |last23=Cook |first23=Neil J. |last24=Doyon |first24=René |last25=Evans-Soma |first25=Thomas M. |last26=Larue |first26=Pierre |last27=Suárez Mascareño |first27=Alejandro |last28=Wardenier |first28=Joost P. |title=Possible Evidence for the Presence of Volatiles on the Warm Super-Earth TOI-270 B |journal=The Astronomical Journal |date=2025 |volume=170 |issue=4 |page=226 |doi=10.3847/1538-3881/adfc6a |doi-access=free |arxiv=2509.14224}}</ref>
{{Orbitbox planet begin | name = TOI-270 | table_ref = <ref name="VanEylen2021"/><ref name="Kaye2022"/><ref name="Coulombe2025" /> }} {{Orbitbox planet | exoplanet = b | mass_earth = {{val|1.48|0.18}} | radius_earth = {{val|1.306|0.028}} | semimajor = {{val|0.03197|(22)}} | period = {{val|3.3601538|(48)}} | eccentricity = {{val|0.0167|(84)}} | inclination = {{val|89.41|0.43}} }} {{Orbitbox planet | exoplanet = c | mass_earth = {{val|6.20|0.31}} | radius_earth = {{val|2.355|0.064}} | semimajor = {{val|0.04526|(31)}} | period = {{val|5.6605731|(31)}} | eccentricity = {{val|0.0044|(6)}} | inclination = {{val|89.36|0.24}} }} {{Orbitbox planet | exoplanet = d | mass_earth = {{val|4.20|0.16}} | radius_earth = {{val|2.133|0.058}} | semimajor = {{val|0.07210|(50)}} | period = {{val|11.379573|(13)}} | eccentricity = {{val|0.0066|(20)}} | inclination = {{val|89.73|0.16}} }} {{Orbitbox end}}
[[File:TOI 270 v Jupiter system.jpg|thumb|700px|center|Comparison of the TOI-270 planetary system to Jupiter's moon system<ref name="NASA-20190729"/>]]
thumb|Artist's impression of the three known planets in the TOI-270 system and their size comparison with Earth
==References== <references>
<ref name="SIMBAD">{{cite simbad |title=L 231-32 |access-date=18 October 2023}}</ref>
<ref name="GaiaDR3">{{Cite Gaia DR3|4781196115469953024}}</ref>
<ref name="Günther2019">{{cite journal |last1=Günther |first1=Maximilian N. |last2=Pozuelos |first2=Francisco J. |display-authors=etal |date=July 2019 |title=A super-Earth and two sub-Neptunes transiting the nearby and quiet M dwarf TOI-270 |journal=Nature Astronomy |volume=3 |issue= 12|pages=1099–1108 |doi=10.1038/s41550-019-0845-5 |arxiv=1903.06107 |bibcode=2019NatAs...3.1099G|s2cid=256707535 }}</ref>
<ref name="NASA-20190729">{{cite web |url=https://www.nasa.gov/universe/nasas-tess-mission-scores-hat-trick-with-3-new-worlds/ |title=NASA's TESS Mission Scores 'Hat Trick' With 3 New Worlds |last=Reddy |first=Francis |date=29 July 2019 |publisher=NASA |access-date=18 October 2023}}</ref>
<ref name="Chouqar2020">{{cite journal |last1=Chouqar |first1=J. |last2=Benkhaldoun |first2=Z. |display-authors=etal |date=June 2020 |title=Properties of sub-Neptune atmospheres: TOI-270 system |journal=Monthly Notices of the Royal Astronomical Society |volume=495 |issue=1 |pages=962–970 |doi=10.1093/mnras/staa1198 |doi-access=free |arxiv=2004.12475 |bibcode=2020MNRAS.495..962C}}</ref>
<ref name="VanEylen2021">{{cite journal |last1=Van Eylen |first1=V. |last2=Astudillo-Defru |first2=N. |display-authors=etal |date=October 2021 |title=Masses and compositions of three small planets orbiting the nearby M dwarf L231-32 (TOI-270) and the M dwarf radius valley |journal=Monthly Notices of the Royal Astronomical Society |volume=507 |issue=2 |pages=2154–2173 |doi=10.1093/mnras/stab2143 |doi-access=free |arxiv=2101.01593 |bibcode=2021MNRAS.507.2154V}}</ref>
<ref name="Kaye2022">{{cite journal |last1=Kaye |first1=Laurel |last2=Vissapragada |first2=Shreyas |display-authors=etal |date=March 2022 |title=Transit Timing Variations in the three-planet system: TOI-270 |journal=Monthly Notices of the Royal Astronomical Society |volume=510 |issue=4 |pages=5464–5485 |doi=10.1093/mnras/stab3483 |doi-access=free |arxiv=2308.10763 |bibcode=2022MNRAS.510.5464K}}</ref>
<ref name="Mikal-Evans2023">{{cite journal |last1=Mikal-Evans |first1=Thomas |last2=Madhusudhan |first2=Nikku |display-authors=etal |date=March 2023 |title=Hubble Space Telescope Transmission Spectroscopy for the Temperate Sub-Neptune TOI-270 d: A Possible Hydrogen-rich Atmosphere Containing Water Vapor |journal=The Astronomical Journal |volume=165 |issue=3 |pages=84 |doi=10.3847/1538-3881/aca90b |arxiv=2211.15576 |bibcode=2023AJ....165...84M |doi-access=free }}</ref>
</references>
{{Pictor}}
Category:Pictor Category:M-type main-sequence stars Category:Planetary systems with three confirmed planets 0270 Category:Extraterrestrial water