TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
Barclay, Thomas; Hellier, Coel; Triaud, Amaury H. M. J.; Bieryla, Allyson; Latham, David W.; Güdel, Manuel; Wheatley, Peter J.; Kane, Stephen R.; Bayliss, Daniel; Wittenmyer, Robert A.; Howell, Steve B.; Horne, Keith; Collins, Karen A.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Caldwell, Douglas A.; Guillot, Tristan; Abe, Lyu; Bendjoya, Philippe; Crouzet, Nicolas; Dransfield, Georgina; Günther, Maximilian N.; Mékarnia, Djamel; Suarez, Olga; Teske, Johanna; Shporer, Avi; Collins, Kevin I.; Gandolfi, Davide; Cabrera, Juan; Eigmüller, Philipp; Fridlund, Malcolm; Persson, Carina M.; Rauer, Heike; Henderson, Beth A.; Casewell, Sarah L.; Goad, Michael R.; Alves, Douglas R.; Armstrong, David J.; Burleigh, Matthew R.; Jenkins, James S.; Kendall, Alicia; Lendl, Monika; Osborn, Ares; Udry, Stéphane; Gillon, Michaël; Delrez, Laetitia; Jensen, Eric L. N.; Kielkopf, John F.; Smith, Alexis M. S.; Bryant, Edward M.; Bonfanti, Andrea; Piotto, Giampaolo; Queloz, Didier; Bouchy, François; Nielsen, Louise D.; Osborn, Hugh P.; Maxted, Pierre F. L.; Irwin, Jonathan M.; Charbonneau, David; Plavchan, Peter; Barrado, David; Demory, Brice-Olivier; Schwarz, Richard P.; Thomas, Nicolas; Brandeker, Alexis; Olofsson, Göran; Heng, Kevin; Sousa, Sérgio G.; Anglada-Escudé, Guillem; Ricker, George; Zhang, Hui; Cloutier, Ryan; Goeke, Robert F.; Wang, Sharon X.; Conti, Dennis M.; Essack, Zahra; Lillo-Box, Jorge; Bonfils, Xavier; Lovis, Christophe; Adibekyan, Vardan; Delgado-Mena, Elisa; Hoyer, Sergio; Dumusque, Xavier; Hadjigeorghiou, Andreas; Hawthorn, Faith; Santos, Nuno C.; Wilson, Thomas G.; Demangeon, Olivier D. S.; Deleuil, Magali; Ehrenreich, David; Srdoc, Gregor; Pallé, Enric; Pollacco, Don; Addison, Brett C.; Ségransan, Damien; Acton, Jack S.; Tilbrook, Rosanna H.; Walton, Nicholas; Barros, Susana C. C.; Brown, David J. A.; Massey, Bob; Alibert, Yann; Santerne, Alexandre; Hooton, Matthew J.; Davies, Melvyn B.; Ribas, Ignasi; O'Brien, Sean M.; Fossati, Luca; Collier Cameron, Andrew; Fortier, Andrea; Schmider, François-Xavier; Buttu, Marco; Baumjohann, Wolfgang; Ragazzoni, Roberto; Lacedelli, Gaia; Nascimbeni, Valerio; Pagano, Isabella; Scandariato, Gaetano; Szabó, Gyula M.; Broeg, Christopher; Egger, Jo Ann; Alonso, Roi; Bárczy, Tamas; Benz, Willy; Kiss, Laszlo L.; Laskar, Jacques; Simon, Attila E.; Steller, Manfred; Van Grootel, Valérie; Leleu, Adrien; Salmon, Sébastien; Gnilka, Crystal; Agabi, Karim; Charnoz, Sébastian; Czismadia, Szilárd; Erickson, Anders; Gillard, Harvey; Etangs, Alain Lecavalier des; Masters, Tamzin
United Kingdom, Austria, Portugal, Switzerland, United States, France, Australia, Spain, Chile, Hungary, Sweden, Germany, Netherlands, Belgium, Italy, Croatia, China
Abstract
We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright (T = 8.5 mag), high proper motion (~200 mas yr-1), low metallicity ([Fe/H]≈-0.28) K-dwarf with a mass of 0.68 ± 0.05 M⊙ and a radius of 0.67 ± 0.01 R⊙. We obtain photometric follow-up observations with a variety of facilities, and we use these data sets to determine that the inner planet, TOI-836 b, is a 1.70 ± 0.07 R⊕ super-Earth in a 3.82-d orbit, placing it directly within the so-called 'radius valley'. The outer planet, TOI-836 c, is a 2.59 ± 0.09 R⊕ mini-Neptune in an 8.60-d orbit. Radial velocity measurements reveal that TOI-836 b has a mass of 4.5 ± 0.9 M⊕, while TOI-836 c has a mass of 9.6 ± 2.6 M⊕. Photometric observations show Transit Timing Variations (TTVs) on the order of 20 min for TOI-836 c, although there are no detectable TTVs for TOI-836 b. The TTVs of planet TOI-836 c may be caused by an undetected exterior planet.