TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
Faith Hawthorn, Daniel Bayliss, T. G. Wilson, A. Bonfanti, V. Adibekyan, Y. Alibert, S. G. Sousa, Karen A. Collins, Edward M. Bryant, Ares Osborn, D. J. Armstrong, Lyu Abe, Jack S Acton, Brett Addison, Karim Agabi, R. Alonso, D. R. Alves, G. Anglada‐Escudé, T. Bárczy, Thomas Barclay, D. Barrado, S. C. C. Barros, W. Baumjohann, Philippe Bendjoya, W. Benz, Allyson Bieryla, X. Bonfıls, F. Bouchy, A. Brandeker, C. Broeg, D. J. A. Brown, M. R. Burleigh, Marco Buttu, Juan Cabrera, Douglas A. Caldwell, S. L. Casewell, David Charbonneau, Sébastian Charnoz, Ryan Cloutier, A. Collier Cameron, Kevin I. Collins, Dennis M. Conti, Nicolas Crouzet, Szilárd Czismadia, M. B. Davies, M. Deleuil, E. Delgado Mena, L. Delrez, O. D. S. Demangeon, Brice-Olivier Demory, Georgina Dransfield, X. Dumusque, J. A. Egger, D. Ehrenreich, Philipp Eigmüller, Anders Erickson, Zahra Essack, A. Fortier, L. Fossati, M. Fridlund, Maximilian N. Günther, M. Güdel, D. Gandolfi, Harvey Gillard, M. Gillon, Crystal L. Gnilka, M. R. Goad, Robert F. Goeke, T. Guillot, Andreas Hadjigeorghiou, C. Hellier, Beth A Henderson, Kevin Heng, M. J. Hooton, K. Horne, Steve B. Howell, S. Hoyer, Jonathan Irwin, J. S. Jenkins, Jon M. Jenkins, Eric L. N. Jensen, Stephen R. Kane, Alicia Kendall, John F. Kielkopf, L. L. Kiss, G. Lacedelli, J. Laskar, David W. Latham, Alain Lecavalier des Etangs, A. Leleu, M. Lendl, J. Lillo-Box, C. Lovis, D. Mékarnia, Bob Massey, Tamzin Masters, P. F. L. Maxted, V. Nascimbeni, Louise D. Nielsen, Sean O'Brien
Abstract
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.