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A Pair of TESS Planets Spanning the Radius Valley around the Nearby Mid-M Dwarf LTT 3780

Cloutier, Ryan and Eastman, Jason D. and Rodriguez, Joseph E. and Astudillo-Defru, Nicola and Bonfils, Xavier and Mortier, Annelies and Watson, Christopher A. and Stalport, Manu and Pinamonti, Matteo and Lienhard, Florian and Harutyunyan, Avet and Damasso, Mario and Latham, David W. and Collins, Karen A. and Massey, Robert and Irwin, Jonathan and Winters, Jennifer G. and Charbonneau, David and Ziegler, Carl and Matthews, Elisabeth and Crossfield, Ian J. M. and Kreidberg, Laura and Quinn, Samuel N. and Ricker, George and Vanderspek, Roland and Seager, Sara and Winn, Joshua and Jenkins, Jon M. and Vezie, Michael and Udry, Stéphane and Twicken, Joseph D. and Tenenbaum, Peter and Sozzetti, Alessandro and Ségransan, Damien and Schlieder, Joshua E. and Sasselov, Dimitar and Santos, Nuno C. and Rice, Ken and Rackham, Benjamin V. and Poretti, Ennio and Piotto, Giampaolo and Phillips, David and Pepe, Francesco and Molinari, Emilio and Mignon, Lucile and Micela, Giuseppina and Melo, Claudio and de Medeiros, José R. and Mayor, Michel and Matson, Rachel A. and Martinez Fiorenzano, Aldo F. and Mann, Andrew W. and Magazzú, Antonio and Lovis, Christophe and López-Morales, Mercedes and Lopez, Eric and Lissauer, Jack J. and Lépine, Sébastien and Law, Nicholas and Kielkopf, John F. and Johnson, John A. and Jensen, Eric L. N. and Howell, Steve B. and Gonzales, Erica and Ghedina, Adriano and Forveille, Thierry and Figueira, Pedro and Dumusque, Xavier and Dressing, Courtney D. and Doyon, René and Díaz, Rodrigo F. and Fabrizio, Luca Di and Delfosse, Xavier and Cosentino, Rosario and Conti, Dennis M. and Collins, Kevin I. and Cameron, Andrew Collier and Ciardi, David and Caldwell, Douglas A. and Burke, Christopher and Buchhave, Lars and Briceño, César and Boyd, Patricia and Bouchy, François and Beichman, Charles and Artigau, Étienne and Almenara, Jose M. (2020) A Pair of TESS Planets Spanning the Radius Valley around the Nearby Mid-M Dwarf LTT 3780. Astronomical Journal, 160 (1). Art. No. 3. ISSN 1538-3881. doi:10.3847/1538-3881/ab91c2.

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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, K_s = 8.204, R_s = 0.374 R⊙, M_s = 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 P_b = 0.77, P_c = 12.25 days and sizes r_(p,b) = 1.33 ± 0.07, r_(p,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^(+0.48)_(−0.46) and m_(p,c) = 8.6^(+1.6)_(−1.3) 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Cloutier, Ryan0000-0001-5383-9393
Eastman, Jason D.0000-0003-3773-5142
Rodriguez, Joseph E.0000-0001-8812-0565
Mortier, Annelies0000-0001-7254-4363
Pinamonti, Matteo0000-0002-4445-1845
Lienhard, Florian0000-0003-4047-0771
Latham, David W.0000-0001-9911-7388
Collins, Karen A.0000-0001-6588-9574
Massey, Robert0000-0001-8879-7138
Winters, Jennifer G.0000-0001-6031-9513
Charbonneau, David0000-0002-9003-484X
Ziegler, Carl0000-0002-0619-7639
Matthews, Elisabeth0000-0003-0593-1560
Kreidberg, Laura0000-0003-0514-1147
Quinn, Samuel N.0000-0002-8964-8377
Ricker, George0000-0003-2058-6662
Vanderspek, Roland0000-0001-6763-6562
Seager, Sara0000-0002-6892-6948
Winn, Joshua0000-0002-4265-047X
Jenkins, Jon M.0000-0002-4715-9460
Udry, Stéphane0000-0001-7576-6236
Twicken, Joseph D.0000-0002-6778-7552
Tenenbaum, Peter0000-0002-1949-4720
Sozzetti, Alessandro0000-0002-7504-365X
Ségransan, Damien0000-0003-2355-8034
Schlieder, Joshua E.0000-0001-5347-7062
Sasselov, Dimitar0000-0001-7014-1771
Santos, Nuno C.0000-0003-4422-2919
Rackham, Benjamin V.0000-0002-3627-1676
Poretti, Ennio0000-0003-1200-0473
Piotto, Giampaolo0000-0002-9937-6387
Molinari, Emilio0000-0002-1742-7735
Micela, Giuseppina0000-0002-9900-4751
de Medeiros, José R.0000-0001-8218-1586
Matson, Rachel A.0000-0001-7233-7508
Mann, Andrew W.0000-0003-3654-1602
Magazzú, Antonio0000-0003-1259-4371
López-Morales, Mercedes0000-0003-3204-8183
Lissauer, Jack J.0000-0001-6513-1659
Law, Nicholas0000-0001-9380-6457
Kielkopf, John F.0000-0003-0497-2651
Jensen, Eric L. N.0000-0002-4625-7333
Howell, Steve B.0000-0002-2532-2853
Ghedina, Adriano0000-0003-4702-5152
Forveille, Thierry0000-0003-0536-4607
Figueira, Pedro0000-0001-8504-283X
Dumusque, Xavier0000-0002-9332-2011
Dressing, Courtney D.0000-0001-8189-0233
Díaz, Rodrigo F.0000-0001-9289-5160
Conti, Dennis M.0000-0003-2239-0567
Collins, Kevin I.0000-0003-2781-3207
Ciardi, David0000-0002-5741-3047
Caldwell, Douglas A.0000-0003-1963-9616
Burke, Christopher0000-0002-7754-9486
Buchhave, Lars0000-0003-1605-5666
Boyd, Patricia0000-0003-0442-4284
Beichman, Charles0000-0002-5627-5471
Additional Information:© 2020 The American Astronomical Society. Received 2020 March 2; revised 2020 April 27; accepted 2020 May 8; published 2020 June 4. R.C. is supported by a grant from the National Aeronautics and Space Administration in support of the TESS science mission. We thank Amber Medina for assistance with detrending the TESS light curve. We thank Sam Hadden for discussions regarding the TTV analysis. We also thank the anonymous referee for comments that helped to improve the completeness of our paper. N.A.D. acknowledges support from FONDECYT 3180063. A.M. acknowledges support from the senior Kavli Institute Fellowships. J.G.W. is supported by a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. C.Z. is supported by a Dunlap Fellowship at the Dunlap Institute for Astronomy & Astrophysics, funded through an endowment established by the Dunlap family and the University of Toronto. I.J.M.C. acknowledges support from the NSF through grant AST-1824644 and NASA through Caltech/JPL grant RSA-1610091. F.L. gratefully acknowledges a scholarship from the Fondation Zd̆nek et Michaela Bakala. M.S. thanks the Swiss National Science Foundation (SNSF) and Geneva University for their continuous support of our exoplanet researches. This work has been in particular carried out in the frame of the National Center for Competence in Research "PlanetS" supported by SNSF. C.A.W. acknowledges support from Science and Technology Facilities Council grant ST/P000312/1. N.C.S. acknowledges supported by FCT, Fundação para a Ciência e a Tecnologia, through national funds and by FEDER through COMPETE2020, Programa Operacional Competitividade e Internacionalização, by these grants: UID/FIS/04434/2019, UIDB/04434/2020, UIDP/04434/2020, PTDC/FIS-AST/32113/2017 & POCI-01-0145-FEDER-032113, PTDC/FIS-AST/28953/2017 & POCI-01-0145-FEDER-028953. M.Pi. gratefully acknowledges support from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 313014 (ETAEARTH). J.R.M. acknowledges support by the CAPES, CNPq, and FAPERN Brazilian agencies. This work has been partially supported by the National Aeronautics and Space Administration under grant No. NNX17AB59G issued through the Exoplanets Research Program. We acknowledge the use of public TESS Alert data from the pipelines at the TESS Science Office and the TESS Science Processing Operations Center. This work makes use of observations acquired with the T150 telescope at Sierra Nevada Observatory, operated by the Instituto de Astrofísica de Andalucía (IAA-CSIC). The MEarth Team gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering (awarded to D.C.). This material is based upon work supported by the National Science Foundation under grants AST-0807690, AST-1109468, AST-1004488 (Alan T. Waterman Award), and AST-1616624. This work is made possible by a grant from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. This material is based upon work supported by the National Aeronautics and Space Administration under grant No. 80NSSC18K0476 issued through the XRP Program. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC; Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work makes use of observations from the LCOGT network. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This work was supported by the French National Research Agency in the framework of the Investissements d'Avenir program (ANR-15-IDEX-02) through the funding of the "Origin of Life" project of the Univ. Grenoble-Alpes. Facilities: TESS - , FLWO:1.5m, LCOGT - , OSN - , TRAPPIST-North - , MEarth-North - , SOAR - , Gemini/NIRI - , ESO 3.6 m/HARPS - , TNG/HARPS-N. - Software: AstroImageJ (Collins et al. 2017), astropy (Astropy Collaboration et al. 2013, 2018), BANZAI (McCully et al. 2018), batman (Kreidberg 2015), BGLS (Mortier et al. 2015), celerite (Foreman-Mackey et al. 2017), emcee (Foreman-Mackey et al. 2013), EvapMass (Owen & Campos Estrada 2020), EXOFAST (Eastman et al. 2013), EXOFASTv2 (Eastman et al. 2019), exoplanet (Foreman-Mackey et al. 2019), forecaster (Chen & Kipping 2017), PandExo (Batalha et al. 2017), PyMC3 (Salvatier et al. 2016), scipy (Virtanen et al. 2020), STARRY (Luger et al. 2019), Tapir (Jensen 2013), TERRA (Anglada-Escudé & Butler 2012), TTV2Fast2Furious (Hadden 2019).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)3180063
Kavli Institute for Cosmological PhysicsUNSPECIFIED
John Templeton FoundationUNSPECIFIED
Dunlap Institute for Astronomy and AstrophysicsUNSPECIFIED
University of TorontoUNSPECIFIED
Fondation Zd̆nek et Michaela BakalaUNSPECIFIED
Swiss National Science Foundation (SNSF)UNSPECIFIED
Geneva UniversityUNSPECIFIED
Science and Technology Facilities Council (STFC)ST/P000312/1
Fondo Europeo de Desarrollo Regional (FEDER)COMPETE2020
Fundação para a Ciência e a Tecnologia (FCT)UID/FIS/04434/2019
Fundação para a Ciência e a Tecnologia (FCT)UIDB/04434/2020
Fundação para a Ciência e a Tecnologia (FCT)UIDP/04434/2020
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS-AST/32113/2017
Fundação para a Ciência e a Tecnologia (FCT)POCI-01-0145-FEDER-032113
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS-AST/28953/2017
Fundação para a Ciência e a Tecnologia (FCT)POCI-01-0145-FEDER-028953
European Research Council (ERC)313014
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Foundation for Research Support of Rio Grande do Norte (FAPERN)UNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-15-IDEX-02
Subject Keywords:Radial velocity ; M dwarf stars ; Exoplanet systems ; Transit photometry
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Radial velocity (1332); M dwarf stars (982); Exoplanet systems (484); Transit photometry (1709)
Record Number:CaltechAUTHORS:20200608-082742388
Persistent URL:
Official Citation:Ryan Cloutier et al 2020 AJ 160 3
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103739
Deposited By: Tony Diaz
Deposited On:08 Jun 2020 15:43
Last Modified:16 Nov 2021 18:24

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