TOI-2084 b and TOI-4184 b : two new sub-Neptunes around M dwarf stars
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We present the discovery and validation of two TESS exoplanets orbiting nearby M dwarfs: TOI-2084 b, and TOI-4184b. We characterized the host stars by combining spectra from Shane/Kast and Magellan/FIRE, spectral energy distribution analysis, and stellar evolutionary models. In addition, we used Gemini-South/Zorro & -North/Alopeke high-resolution imaging, archival science images, and statistical validation packages to support the planetary interpretation. We performed a global analysis of multi-colour photometric data from TESS and ground-based facilities in order to derive the stellar and planetary physical parameters for each system. We find that TOI-2084 band TOI-4184 bare sub-Neptune-sized planets with radii of Rp = 2.47 ± 0.13R⊕ and Rp = 2.43 ± 0.21 R⊕, respectively. TOI-2084 b completes an orbit around its host star every 6.08 days, has an equilibrium temperature of Teq = 527 ± 8 K and an irradiation of Sp = 12.8 ± 0.8 S⊕. Its host star is a dwarf of spectral M2.0 ± 0.5 at a distance of 114 pc with an effective temperature of Teff = 3550 ± 50 K, and has a wide, co-moving M8 companion at a projected separation of 1400 au. TOI-4184 b orbits around an M5.0 ± 0.5 type dwarf star (Kmag = 11.87) each 4.9 days, and has an equilibrium temperature of Teq = 412 ± 8 K and an irradiation of Sp = 4.8 ± 0.4 S⊕. TOI-4184 is a metal poor star ([Fe/H] = −0.27 ± 0.09 dex) at a distance of 69 pc with an effective temperature of Teff = 3225 ± 75 K. Both planets are located at the edge of the sub-Jovian desert in the radius-period plane. The combination of the small size and the large infrared brightness of their host stars make these new planets promising targets for future atmospheric exploration with JWST.
Barkaoui , K , Timmermans , M , Soubkiou , A , Rackham , B V , Burgasser , A J , Chouqar , J , Pozuelos , F J , Collins , K A , Howell , S B , Simcoe , R , Melis , C , Stassun , K G , Tregloan-Reed , J , Cointepas , M , Gillon , M , Bonfils , X , Furlan , E , Gnilka , C L , Almenara , J M , Alonso , R , Benkhaldoun , Z , Bonavita , M , Bouchy , F , Burdanov , A , Chinchilla , P , Davoudi , F , Delrez , L , Demangeon , O , Dominik , M , Demory , B -O , de Wit , J , Dransfield , G , Ducrot , E , Fukui , A , Hinse , T C , Hooton , M J , Jehin , E , Jenkins , J M , Jørgensen , U G , Latham , D W , Garcia , L , Carrazco-Gaxiola , S , Ghachoui , M , Gómez Maqueo Chew , Y , Günther , M N , McCormac , J , Murgas , F , Murray , C A , Narita , N , Niraula , P , Pedersen , P P , Queloz , D , Rebolo-López , R , Ricker , G , Sabin , L , Sajadian , S , Schanche , N , Schwarz , R P , Seager , S , Sebastian , D , Sefako , R , Sohy , S , Southworth , J , Srdoc , G , Thompson , S J , Triaud , A H M J , Vanderspek , R , Wells , R D , Winn , J N & Zúñiga-Fernández , S 2023 , ' TOI-2084 b and TOI-4184 b : two new sub-Neptunes around M dwarf stars ' , Astronomy & Astrophysics , vol. 677 , A38 . https://doi.org/10.1051/0004-6361/202346838
Astronomy & Astrophysics
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DescriptionFunding: The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. This research is in part funded by the European Union’s Horizon 2020 research and innovation program (grants agreements n◦ 803193/BEBOP), and from the Science and Technology Facilities Council (STFC; grant n◦ ST/S00193X/1). U.G.J. gratefully acknowledges support from tthe European Union H2020-MSCA-ITN-2019 under grant No. 860470 (CHAMELEON). The authors acknowledge funding from the European Research Council under the ERC Grant Agreement n. 337591-ExTrA.
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