TOI-2136 b

{{Short description|Exoplanet in TOI-2136 star system}} {{Infobox planet | extrasolarplanet = yes | name = TOI-2136 b | apsis = astron | discovery_ref = <ref name="Gan2022"/> | discoverer = Tianjun Gan et al. (2022) | discovery_site = TESS | discovered = 2022 | discovery_method = Radial velocity | semimajor = | eccentricity = | period = | inclination = | semi-amplitude = | star = TOI-2136 | physical_ref = <ref name="Gan2022"/> | mean_radius = 2.19±0.17 | mass = {{Val|6.37|2.45|2.29}} }}

'''TOI-2136 b''' is a sub-Neptune exoplanet orbiting the nearby red dwarf star TOI-2136.<ref name="Gan2022"/> It was discovered in 2022 through transit observations by NASA's TESS and independently validated using ground-based photometry and radial velocity measurements.<ref name="Gan2022">{{cite journal |last=Gan |first=Tianjun |title=TESS discovery of a sub-Neptune around the mid-M dwarf TOI-2136 |journal=Monthly Notices of the Royal Astronomical Society |volume=514 |issue=3 |pages=4120–4132 |year=2022 |doi=10.1093/mnras/stac1554 |doi-access=free }}</ref><ref name=":0">{{Cite journal |last1=Kawauchi |first1=K. |last2=Murgas |first2=F. |last3=Palle |first3=E. |last4=Narita |first4=N. |last5=Fukui |first5=A. |last6=Hirano |first6=T. |last7=Parviainen |first7=H. |last8=Ishikawa |first8=H. T. |last9=Watanabe |first9=N. |last10=Esparaza-Borges |first10=E. |last11=Kuzuhara |first11=M. |last12=Orell-Miquel |first12=J. |last13=Krishnamurthy |first13=V. |last14=Mori |first14=M. |last15=Kagetani |first15=T. |date=2022-10-01 |title=Validation and atmospheric exploration of the sub-Neptune TOI-2136b around a nearby M3 dwarf |url=https://www.aanda.org/articles/aa/abs/2022/10/aa43381-22/aa43381-22.html |journal=Astronomy & Astrophysics |language=en |volume=666 |pages=A4 |doi=10.1051/0004-6361/202243381 |bibcode=2022A&A...666A...4K |issn=0004-6361}}</ref> The planet has an orbital period of approximately 7.85 days and lies at a distance of about 108 light-years from Earth.<ref>{{Cite web |title=TOI-2136 {{!}} NASA Exoplanet Archive |url=https://exoplanetarchive.ipac.caltech.edu/overview/TOI-2136 |access-date=2026-04-09 |website=exoplanetarchive.ipac.caltech.edu}}</ref><ref>{{Cite journal |last=Soubkiou |first=A. |last2=Barkaoui |first2=K. |last3=Gan |first3=T. |last4=Benkhaldoun |first4=Z. |date=2024 |title=Discovery of Three Sub-Neptune Exoplanets Orbiting M Dwarfs with TESS |url=https://www.cambridge.org/core/journals/proceedings-of-the-international-astronomical-union/article/discovery-of-three-subneptune-exoplanets-orbiting-m-dwarfs-with-tess/34B3B83A7349A61F798D59E1C956A4CD |journal=Proceedings of the International Astronomical Union |language=en |volume=20 |issue=S393 |pages=187–195 |doi=10.1017/S174392132400262X |issn=1743-9213}}</ref> TOI-2136 b is known for its position near the red dwarf for planets predicted by atmospheric mass-loss models and for its potential as a hycean world.<ref name="Gan2022"/><ref name=":0" />

== Discovery == TOI-2136 b was first identified as the candidate TOI-2136.01 from photometric data collected during TESS's primary mission.<ref name="Gan2022"/> The transit signal was detected with an orbital period of 7.85 days around the red dwarf star TOI-2136.<ref name="Gan2022"/>

Independent confirmation came from Gan et al. (2022) who used ground-based multi-wavelength photometry, high-angular-resolution imaging, and precise radial-velocity measurements from the CFHT/SPIRou instrument to validate the planet and measure its mass.<ref name="Gan2022"/> Kawauchi et al. (2022) validated it using TESS data, ground-based photometry, and radial velocities from the Subaru Telescope's IRD instrument, while also conducting a search for helium in its atmosphere<ref name=":0" /> and Beard et al. (2022) provided additional validation using the Habitable-Zone Planet Finder (HPF) on the Hobby-Eberly Telescope, placing an upper mass limit.<ref>{{Cite journal |last1=Beard |first1=Corey |last2=Robertson |first2=Paul |last3=Kanodia |first3=Shubham |last4=Libby-Roberts |first4=Jessica |last5=Cañas |first5=Caleb I. |last6=Gupta |first6=Arvind F. |last7=Holcomb |first7=Rae |last8=Jones |first8=Sinclaire |last9=Kobulnicky |first9=Henry A. |last10=Lin |first10=Andrea S. J. |last11=Lubin |first11=Jack |last12=Maney |first12=Marissa |last13=Parker |first13=Brock A. |last14=Stefánsson |first14=Guðmundur |last15=Cochran |first15=William D. |date=2022-06-01 |title=TOI-1696 and TOI-2136: Constraining the Masses of Two Mini-Neptunes with the Habitable-Zone Planet Finder |journal=The Astronomical Journal |volume=163 |issue=6 |pages=286 |doi=10.3847/1538-3881/ac69ec |doi-access=free |arxiv=2204.09063 |bibcode=2022AJ....163..286B |issn=0004-6256}}</ref>

== Characteristics == The mass–radius combination of TOI-2136 b is compatible with a wide range of interior compositions, from water or ice dominated worlds to gas-enveloped rocky cores.<ref name="Gan2022"/> Interior structure models suggest it may retain a small H/He envelope (mass fraction ~1–2%) atop a rocky or icy core. It lies relatively close to the red dwarfs, where thermally driven atmospheric escape is expected to sculpt planetary populations.<ref name="Gan2022"/>

TOI-2136 b has also been discussed as a potential Cold Haber World, where microbial life could produce detectable ammonia via a process similar to the Haber process under high-pressure ocean conditions and could be a future target for JWST.<ref>{{Cite web |last=Robertson |first=Paul M. |date=2022-09-15 |title=TOI-2136b: Habitable, but not to us? |url=https://hpf.psu.edu/2022/09/15/toi-2136b/ |access-date=2026-04-09 |website=The Habitable Zone Planet Finder |language=en-US}}</ref>

== References == {{Reflist}}

Category:Exoplanets discovered in 2022 Category:Transiting exoplanets Category:Super-Earths