Osborn, Ares; Armstrong, David J.; Cale, Bryson; Brahm, Rafael; Wittenmyer, Robert A.; Dai, Fei; Crossfield, Ian J. M.; Bryant, Edward M.; Adibekyan, Vardan; Cloutier, Ryan; Collins, Karen A.; Mena, E. Delgado; Fridlund, Malcolm; Hellier, Coel; Howell, Steve B.; King, George W.; Lillo-Box, Jorge; Otegi, Jon; Sousa, S.; Stassun, Keivan G.; Matthews, Elisabeth C.; Ziegler, Carl; Ricker, George; Vanderspek, Roland; Latham, David W.; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.; Acton, Jack S.; Addison, Brett C.; Anderson, David R.; Ballard, Sarah; Barrado, David; Barros, Susana C. C.; Batalha, Natalie; Bayliss, Daniel; Barclay, Thomas; Benneke, Bjorn; Berberian, John; Bouchy, Francois; Bowler, Brendan P.; Briceno, Cesar; Burke, Christopher J.; Burleigh, Matthew R.; Casewell, Sarah L.; Ciardi, David; Collins, Kevin, I; Cooke, Benjamin F.; Demangeon, Olivier D. S.; Diaz, Rodrigo F.; Dorn, C.; Dragomir, Diana; Dressing, Courtney; Dumusque, Xavier; Espinoza, Nestor; Figueira, P.; Fulton, Benjamin; Furlan, E.; Gaidos, E.; Geneser, C.; Gill, Samuel; Goad, Michael R.; Gonzales, Erica J.; Gorjian, Varoujan; Gunther, Maximilian N.; Helled, Ravit; Henderson, Beth A.; Henning, Thomas; Hogan, Aleisha; Hojjatpanah, Saeed; Horner, Jonathan; Howard, Andrew W.; Hoyer, Sergio; Huber, Dan; Isaacson, Howard; Jenkins, James S.; Jensen, Eric L. N.; Jordan, Andres; Kane, Stephen R.; Kidwell, Richard C., Jr.; Kielkopf, John; Law, Nicholas; Lendl, Monika; Lund, M.; Matson, Rachel A.; Mann, Andrew W.; McCormac, James; Mengel, Matthew W.; Morales, Farisa Y.; Nielsen, Louise D.; Okumura, Jack; Osborn, Hugh P.; Petigura, Erik A.; Plavchan, Peter; Pollacco, Don; Quintana, Elisa, V; Raynard, Liam; Robertson, Paul; Rose, Mark E.; Roy, Arpita; Reefe, Michael; Santerne, Alexandre; Santos, Nuno C.; Sarkis, Paula; Schlieder, J.; Schwarz, Richard P.; Scott, Nicholas J.; Shporer, Avi; Smith, A. M. S.; Stibbard, C.; Stockdale, Chris; Strom, Paul A.; Twicken, Joseph D.; Tan, Thiam-Guan; Tanner, A.; Teske, J.; Tilbrook, Rosanna H.; Tinney, C. G.; Udry, Stephane; Villasenor, Jesus Noel; Vines, Jose, I; Wang, Sharon X.; Weiss, Lauren M.; West, Richard G.; Wheatley, Peter J.; Wright, Duncan J.; Zhang, Hui; Zohrabi, F.
2021
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
DOI
10.1093/mnras/stab2313
We present the bright (V-mag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 +/- 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Satellite (TESS) objects of Interest (TOI)-431b is a super-Earth with a period of 0.49 d, a radius of 1.28 +/- 0.04 R-circle plus, a mass of 3.07 +/- 0.35 M-circle plus, and a density of 8.0 +/- 1.0 g cm(-3); TOI-431 d is a sub-Neptune with a period of 12.46 d, a radius of 3.29 +/- 0.09 R-circle plus, a mass of M-circle plus, and a density of 1.36 +/- 0.25 g cm(-3). We find a third planet, TOI-431c, in the High Accuracy Radial velocity Planet Searcher RV data, but it is not seen to transit in the TESS light curves. It has an Msin i of M-circle plus, and a period of 4.85 d. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431b is a prime TESS discovery for the study of rocky planet phase curves.