TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
Creators: name: Hawthorn, Faith
name: Bayliss, Daniel
name: Wilson, Thomas G.
name: Bonfanti, Andrea
name: Adibekyan, Vardan
name: Alibert, Yann
name: Sousa, Sérgio G.
name: Collins, Karen A.
name: Bryant, Edward M.
name: Osborn, Ares
name: Armstrong, David J.
name: Abe, Lyu
name: Acton, Jack S.
name: Addison, Brett C.
name: Agabi, Karim
name: Alonso, Roi
name: Alves, Douglas R.
name: Anglada-Escudé, Guillem
name: Bárczy, Tamas
name: Barclay, Thomas
name: Barrado, David
name: Barros, Susana C. C.
name: Baumjohann, Wolfgang
name: Bendjoya, Philippe
name: Benz, Willy
name: Bieryla, Allyson
name: Bonfils, Xavier
name: Bouchy, François
name: Brandeker, Alexis
name: Broeg, Christopher
name: Brown, David J. A.
name: Burleigh, Matthew R.
name: Buttu, Marco
name: Cabrera, Juan
name: Caldwell, Douglas A.
name: Casewell, Sarah L.
name: Charbonneau, David
name: Charnoz, Sébastian
name: Cloutier, Ryan
name: Cameron, Andrew Collier
name: Collins, Kevin I.
name: Conti, Dennis M.
name: Crouzet, Nicolas
name: Czismadia, Szilárd
name: Davies, Melvyn B.
name: Deleuil, Magali
name: Delgado-Mena, Elisa
name: Delrez, Laetitia
name: Demangeon, Olivier D. S.
name: Demory, Brice-Olivier
name: Dransfield, Georgina
name: Dumusque, Xavier
name: Egger, Jo Ann
name: Ehrenreich, David
name: Eigmüller, Philipp
name: Erickson, Anders
name: Essack, Zahra
name: Fortier, Andrea
name: Fossati, Luca
name: Fridlund, Malcolm
name: Günther, Maximilian N.
name: Güdel, Manuel
name: Gandolfi, Davide
name: Gillard, Harvey
name: Gillon, Michaël
name: Gnilka, Crystal
name: Goad, Michael R.
name: Goeke, Robert F.
name: Guillot, Tristan
name: Hadjigeorghiou, Andreas
name: Hellier, Coel
name: Henderson, Beth A.
name: Heng, Kevin
name: Hooton, Matthew J.
name: Horne, Keith
name: Howell, Steve B.
name: Hoyer, Sergio
name: Irwin, Jonathan M.
name: Jenkins, James S.
name: Jenkins, Jon M.
name: Jensen, Eric L. N.
name: Kane, Stephen R.
name: Kendall, Alicia
name: Kielkopf, John F.
name: Kiss, Laszlo L.
name: Lacedelli, Gaia
name: Laskar, Jacques
name: Latham, David W.
name: Etangs, Alain Lecavalier des
name: Leleu, Adrien
name: Lendl, Monika
name: Lillo-Box, Jorge
name: Lovis, Christophe
name: Mékarnia, Djamel
name: Massey, Bob
name: Masters, Tamzin
name: Maxted, Pierre F. L.
name: Nascimbeni, Valerio
name: Nielsen, Louise D.
name: O'Brien, Sean M.
name: Olofsson, Göran
name: Osborn, Hugh P.
name: Pagano, Isabella
name: Pallé, Enric
name: Persson, Carina M.
name: Piotto, Giampaolo
name: Plavchan, Peter
name: Pollacco, Don
name: Queloz, Didier
name: Ragazzoni, Roberto
name: Rauer, Heike
name: Ribas, Ignasi
name: Ricker, George
name: Ségransan, Damien
name: Salmon, Sébastien
name: Santerne, Alexandre
name: Santos, Nuno C.
name: Scandariato, Gaetano
name: Schmider, François-Xavier
name: Schwarz, Richard P.
name: Seager, Sara
name: Shporer, Avi
name: Simon, Attila E.
name: Smith, Alexis M. S.
name: Srdoc, Gregor
name: Steller, Manfred
name: Suarez, Olga
name: Szabó, Gyula M.
name: Teske, Johanna
name: Thomas, Nicolas
name: Tilbrook, Rosanna H.
name: Triaud, Amaury H. M. J.
name: Udry, Stéphane
name: Van Grootel, Valérie
name: Walton, Nicholas
name: Wang, Sharon X.
name: Wheatley, Peter J.
name: Winn, Joshua N.
name: Wittenmyer, Robert A.
name: Zhang, Hui
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: 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 ($\sim\,200$ mas yr$^{-1}$), low metallicity ([Fe/H]$\approx\,-0.28$) K-dwarf with a mass of $0.68\pm0.05$ M$_{\odot}$ and a radius of $0.67\pm0.01$ R$_{\odot}$. 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 $1.70\pm0.07$ R$_{\oplus}$ super-Earth in a 3.82 day orbit, placing it directly within the so-called 'radius valley'. The outer planet, TOI-836 c, is a $2.59\pm0.09$ R$_{\oplus}$ mini-Neptune in an 8.60 day orbit. Radial velocity measurements reveal that TOI-836 b has a mass of $4.5\pm0.9$ M$_{\oplus}$ , while TOI-836 c has a mass of $9.6\pm2.6$ M$_{\oplus}$. Photometric observations show Transit Timing Variations (TTVs) on the order of 20 minutes 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.