A. Osborn, D. J. Armstrong, B. Cale, R. Brahm, R. A. Wittenmyer, F. Dai, I. J. M. Crossfield, E. M. Bryant, V. Zh. Adibekyan, R. Cloutier, K. A. Collins, E. Delgado Mena, M. Fridlund, C. Hellier, S. B. Howell, G. W. King, J. Lillo-Box, J. F. Otegi, S. G. Sousa, K. G. Stassun, E. C. Matthews, C. Ziegler, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, J. S. Acton, B. C. Addison, D. R. Anderson, S. Ballard, D. Barrado, S. C. C. Barros, N. Batalha, D. Bayliss, T. Barclay, B. Benneke, J. Berberian, F. Bouchy, B. P. Bowler, C. Briceño, C. J. Burke, M. Burleigh, S. Casewell, D. Ciardi, K. I. Collins, B. F. Cooke, O. Demangeon, R. F. Díaz, C. Dorn, D. Dragomir, C. D. Dressing, X. Dumusque, N. Espinoza, P. Figueira, B. J. Fulton, E. Furlan, E. Gaidos, C. Geneser, S. Gill, M. R. Goad, E. J. Gonzales, V. Gorjian, M. N. Günther, R. Helled, B. Henderson, T. Henning, A. E. Hogan, S. Hojjatpanah, J. Horner, A. W. Howard, S. Hoyer, D. Huber, H. Isaacson, J. S. Jenkins, E. L. N. Jensen, A. Jordán, S. R. Kane, R. C. Kidwell, J. F. Kielkopf, N. M. Law, M. Lendl, M. N. Lund, R. A. Matson, A. W. Mann, J. McCormac, M. W. Mengel, F. Y. Morales, L. D. Nielsen, J. Okumura, H. P. Osborn, E. Petigura, P. P. Plavchan, D. Pollacco, E. V. Quintana, L. Raynard, P. Robertson, M. Rose, A. Roy, M. Reefe, A. Santerne, N. C. Santos, P. Sarkis, J. E. Schlieder, R. P. Schwarz, N. J. Scott, A. Shporer, A. M. S. Smith, C. Stibbard, C. Stockdale, P. A. Strøm, J. D. Twicken, T.-G. Tan, A. Tanner, J. Teske, R. H. Tilbrook, C. G. Tinney, S. Udry, J. Villaseñor, J. I. Vines, S. X. Wang, L. M. Weiss, R. G. West, P. J. Wheatley, D. Wright, H. Zhang, F. Zohrabi
We present the bright (Vmag = 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)-431 b is a super-Earth with a period of 0.49 d, a radius of 1.28 ± 0.04 R⊕, a mass of 3.07 ± 0.35 M⊕, 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⊕, a mass of 9.90+1.53−1.49 M⊕, and a density of 1.36 ± 0.25 g cm−3. We find a third planet, TOI-431 c, 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 2.83+0.41−0.34 M⊕, and a period of 4.85 d. TOI-431 d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431 b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431 b is a prime TESS discovery for the study of rocky planet phase curves.
planets and satellites: detection, planets and satellites: fundamental parameters, planets and satellites: individual: (TOI-431, TIC 31374837)
Monthly Notices of the Royal Astronomical Society
Volume 507, Issue 2, Page 2782