TESS discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136

• DOI: 10.1093/mnras/stac1448
• Publication Date: 2022-05-31T22:43:30Z
• Authors: Tianjun Gan; Abderahmane Soubkiou; Sharon X Wang; Zouhair Benkhaldoun; Shude Mao; Étienne Artigau; Pascal Fouqué; Luc Arnold; Steven Giacalone; Christopher A The...; Christian Aganze; Adam Burgasser; Karen A Collins; Avi Shporer; Khalid Barkaoui; Mourad Ghachoui; Steve B Howell; Claire Lamman; Olivier D S Deman...; Artem Burdanov; Charles Cadieux; Jamila Chouqar; Kevin I Collins; Neil J Cook; Laetitia Delrez; Brice-Olivier Demory; René Doyon; Georgina Dransfield; Courtney D Dressing; Elsa Ducrot; Jiahao Fan; Lionel Garcia; Holden Gill; Michaël Gillon; Crystal L Gnilka; Yilen Gómez Maque...; Maximilian N Günther; Christopher E Henze; Chelsea X Huang; Emmanuel Jehin; Eric L N Jensen; Zitao Lin; Nadine Manset; James McCormac; Catriona A Murray; Prajwal Niraula; Peter P Pedersen; Francisco J Pozuelos; Didier Queloz; Benjamin V Rackham; Arjun B Savel; Nicole Schanche; Richard P Schwarz; Daniel Sebastian; Samantha Thompson; Mathilde Timmermans; Amaury H M J Triaud; Michael Vezie; Robert D Wells; Julien de Wit; George R Ricker; Roland Vanderspek; David W Latham; Sara Seager; Joshua N Winn; Jon M Jenkins
• Keywords: Astrophysics and Astronomy; planets and satellites: detection; 530 Physics; FOS: Physical sciences; 000 Computer science, knowledge & systems; 01 natural sciences; [SDU] Sciences of the Universe [physics]; 0103 physical sciences; stars: individual: TIC 336128819 – TOI-2136; stars: individual: TIC 336128819 -; planetary systems; Solar and Stellar Astrophysics (astro-ph.SR); QB; Earth and Planetary Astrophysics (astro-ph.EP); 520 Astronomy; Astronomy and Astrophysics; 500 Science; 520; Astrophysics - Solar and Stellar Astrophysics; Space and Planetary Science; [SDU]Sciences of the Universe [physics]; 13. Climate action; stars: individual: TIC 336128819 - TOI-2136; Astrophysics - Earth and Planetary Astrophysics

ABSTRACT We 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 $0.34\pm 0.02 \, \mathrm{M}_{\odot }$, 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.