A Pair of TESS Planets Spanning the Radius Valley around the Nearby Mid-M Dwarf LTT 3780
Date
2020-07Author
Cloutier, Ryan
Eastman, Jason D.
Rodríguez, Joseph E.
Astudillo Defru, Nicola
Bonfils, Xavier
Mortier, Annelies
Watson, Christopher A.
Stalport, Manu
Pinamonti, Matteo
Lienhard, Florian
Harutyunyan, Avet
Damasso, Mario
Latham, David W.
Collins, Karen A.
Massey, Robert
Irwin, Jonathan
Winters, Jennifer G.
Charbonneau, David
Ziegler, Carl
Matthews, Elisabeth
Crossfield, Ian J. M.
Kreidberg, Laura
Quinn, Samuel N.
Ricker, George
Vanderspek, Roland
Seager, Sara
Winn, Joshua
Jenkins, Jon M.
Vezie, Michael
Udry, Stéphane
Twicken, Joseph D.
Tenenbaum, Peter
Sozzetti, Alessandro
Ségransan, Damien
Schlieder, Joshua E.
Sasselov, Dimitar
Santos, Nuno C.
Rice, Ken
Rackham, Benjamin V.
Poretti, Ennio
Piotto, Giampaolo
Phillips, David
Pepe, Francesco
Molinari, Emilio
Mignon, Lucile
Micela, Giuseppina
Melo, Claudio
De Medeiros, José R.
Mayor, Michel
Matson, Rachel A.
Martínez Fiorenzano, Aldo F.
Mann, Andrew W.
Magazzú, Antonio
Lovis, Christophe
López-Morales, Mercedes
López, Eric
Lissauer, Jack J.
Lépine, Sébastien
Law, Nicholas
Kielkopf, John F.
Johnson, John A.
Jensen, Eric L. N.
Howell, Steve B.
Gonzáles, Erica
Ghedina, Adriano
Forveille, Thierry
Figueira, Pedro
Dumusque, Xavier
Dressing, Courtney D.
Doyon, René
Díaz, Rodrigo F.
Di Fabrizio, Luca
Delfosse, Xavier
Cosentino, Rosario
Conti, Dennis M.
Collins, Kevin I.
Collier Cameron, Andrew
Ciardi, David
Caldwell, Douglas A.
Burke, Christopher
Buchhave, Lars
Briceño, César
Boyd, Patricia
Bouchy, François
Beichman, Charles
Artigau, Étienne
Almenara, José Manuel
Publisher
IOPDescription
Artículo de publicación ISIMetadata
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We present the confirmation of two new planets transiting the nearby mid-M dwarf LTT 3780 (TIC 36724087, TOI-732, V = 13.07, Ks = 8.204, Rs = 0.374 R⊙, Ms = 0.401 M⊙, d = 22 pc). The two planet candidates are identified in a single Transiting Exoplanet Survey Satellite sector and validated with reconnaissance spectroscopy, ground-based photometric follow-up, and high-resolution imaging. With measured orbital periods of Pb = 0.77, Pc = 12.25 days and sizes rp,b = 1.33 ± 0.07, rp,c = 2.30 ± 0.16 R⊕, the two planets span the radius valley in period–radius space around low-mass stars, thus making the system a laboratory to test competing theories of the emergence of the radius valley in that stellar mass regime. By combining 63 precise radial velocity measurements from the High Accuracy Radial velocity Planet Searcher (HARPS) and HARPS-N, we measure planet masses of ${m}_{p,b}={2.62}_{-0.46}^{+0.48}$ and ${m}_{p,c}={8.6}_{-1.3}^{+1.6}$ M⊕, which indicates that LTT 3780b has a bulk composition consistent with being Earth-like, while LTT 3780c likely hosts an extended H/He envelope. We show that the recovered planetary masses are consistent with predictions from both photoevaporation and core-powered mass-loss models. The brightness and small size of LTT 3780, along with the measured planetary parameters, render LTT 3780b and c as accessible targets for atmospheric characterization of planets within the same planetary system and spanning the radius valley.