1. TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
- Author
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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, Björn, Berberian Jr., John, Bouchy, Francois, Bowler, Brendan P., Briceño, César, Burke, Christopher J., Burleigh, Matthew R., Casewell, Sarah L., Ciardi, David, Collins, Kevin I., Cooke, Benjamin F., Demangeon, Olivier D. S., Díaz, Rodrigo F., Dorn, C., Dragomir, Diana, Dressing, Courtney, Dumusque, Xavier, Espinoza, Néstor, Figueira, P., Fulton, Benjamin, Furlan, E., Gaidos, E., Geneser, C., Gill, Samuel, Goad, Michael R., Gonzales, Erica J., Gorjian, Varoujan, Günther, 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., Jordán, Andrés, Kane, Stephen R., Kidwell Jr., Richard C., 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, Strøm, Paul A., Twicken, Joseph D., Tan, Thiam-Guan, Tanner, A., Teske, J., Tilbrook, Rosanna H., Tinney, C. G., Udry, Stephane, Villaseñor, Jesus Noel, Vines, Jose I., Wang, Sharon X., Weiss, Lauren M., West, Richard G., Wheatley, Peter J., Wright, Duncan J., Zhang, Hui, and Zohrabi, F.
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We present the bright (V$_{mag} = 9.12$), multi-planet system TOI-431, characterised with photometry and radial velocities. We estimate the stellar rotation period to be $30.5 \pm 0.7$ days using archival photometry and radial velocities. TOI-431b is a super-Earth with a period of 0.49 days, a radius of 1.28 $\pm$ 0.04 R$_{\oplus}$, a mass of $3.07 \pm 0.35$ M$_{\oplus}$, and a density of $8.0 \pm 1.0$ g cm$^{-3}$; TOI-431d is a sub-Neptune with a period of 12.46 days, a radius of $3.29 \pm 0.09$ R$_{\oplus}$, a mass of $9.90^{+1.53}_{-1.49}$ M$_{\oplus}$, and a density of $1.36 \pm 0.25$ g cm$^{-3}$. We find a third planet, TOI-431c, in the HARPS radial velocity data, but it is not seen to transit in the TESS light curves. It has an $M \sin i$ of $2.83^{+0.41}_{-0.34}$ M$_{\oplus}$, and a period of 4.85 days. TOI-431d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterisation, 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., Comment: 21 pages, 11 figures, 3 appendices, accepted for publication in MNRAS
- Published
- 2021
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