Gan, TianjunTianjunGanSoubkiou, AbderahmaneAbderahmaneSoubkiouWang, Sharon XSharon XWangBenkhaldoun, ZouhairZouhairBenkhaldounMao, ShudeShudeMaoArtigau, ÉtienneÉtienneArtigauFouqué, PascalPascalFouquéArnold, LucLucArnoldGiacalone, StevenStevenGiacaloneTheissen, Christopher AChristopher ATheissenAganze, ChristianChristianAganzeBurgasser, AdamAdamBurgasserCollins, Karen AKaren ACollinsShporer, AviAviShporerBarkaoui, KhalidKhalidBarkaouiGhachoui, MouradMouradGhachouiHowell, Steve BSteve BHowellLamman, ClaireClaireLammanDemangeon, Olivier D SOlivier D SDemangeonBurdanov, ArtemArtemBurdanovCadieux, CharlesCharlesCadieuxChouqar, JamilaJamilaChouqarCollins, Kevin IKevin ICollinsCook, Neil JNeil JCookDelrez, LaetitiaLaetitiaDelrezDemory, Brice-OlivierBrice-OlivierDemory0000-0002-9355-5165Doyon, RenéRenéDoyonDransfield, GeorginaGeorginaDransfieldDressing, Courtney DCourtney DDressingDucrot, ElsaElsaDucrotFan, JiahaoJiahaoFanGarcia, LionelLionelGarciaGill, HoldenHoldenGillGillon, MichaëlMichaëlGillonGnilka, Crystal LCrystal LGnilkaGómez Maqueo Chew, YilenYilenGómez Maqueo ChewGünther, Maximilian NMaximilian NGüntherHenze, Christopher EChristopher EHenzeHuang, Chelsea XChelsea XHuangJehin, EmmanuelEmmanuelJehinJensen, Eric L NEric L NJensenLin, ZitaoZitaoLinManset, NadineNadineMansetMcCormac, JamesJamesMcCormacMurray, Catriona ACatriona AMurrayNiraula, PrajwalPrajwalNiraulaPedersen, Peter PPeter PPedersenPozuelos, Francisco JFrancisco JPozuelosQueloz, DidierDidierQuelozRackham, Benjamin VBenjamin VRackhamSavel, Arjun BArjun BSavelSchanche, NicoleNicoleSchanche0000-0002-9526-3780Schwarz, Richard PRichard PSchwarzSebastian, DanielDanielSebastianThompson, SamanthaSamanthaThompsonTimmermans, MathildeMathildeTimmermansTriaud, Amaury H M JAmaury H M JTriaudVezie, MichaelMichaelVezieWells, Robert DonaldRobert DonaldWells0000-0002-7240-8473de Wit, JulienJuliende WitRicker, George RGeorge RRickerVanderspek, RolandRolandVanderspekLatham, David WDavid WLathamSeager, SaraSaraSeagerWinn, Joshua NJoshua NWinnJenkins, Jon MJon MJenkins2024-10-252024-10-252022-08https://boris-portal.unibe.ch/handle/20.500.12422/165842We present the discovery of TOI-2136 b, a sub-Neptune planet transiting a nearby M4.5V-type star every 7.85 d, identified through photometric measurements from the Transiting Exoplanet Survey Satellite (TESS) mission. The host star is located 33 pc away with a radius of R* = 0.34 ± 0.02 R⊙, a mass of 0.34±0.02M⊙ ⁠, and an effective temperature of 3342 ± 100 K. We estimate its stellar rotation period to be 75 ± 5 d based on archival long-term photometry. We confirm and characterize the planet based on a series of ground-based multiwavelength photometry, high-angular-resolution imaging observations, and precise radial velocities from Canada–France–Hawaii Telescope (CFHT)/SpectroPolarimètre InfraROUge (SPIRou). Our joint analysis reveals that the planet has a radius of 2.20 ± 0.17 R⊕ and a mass of 6.4 ± 2.4 M⊕. The mass and radius of TOI-2136 b are consistent with a broad range of compositions, from water-ice to gas-dominated worlds. TOI-2136 b falls close to the radius valley for M dwarfs predicted by thermally driven atmospheric mass-loss models, making it an interesting target for future studies of its interior structure and atmospheric properties.en500 - Science::530 - Physics500 - Science::520 - Astronomy000 - Computer science, knowledge & systems500 - Sciencearticle10.48350/18095710.1093/mnras/stac1448