1. Planetary system LHS 1140 revisited with ESPRESSO and TESS
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L. Acuña, Nathan Hara, Nuno C. Santos, David Barrado, João P. Faria, Emmanuel Marcq, Nicola Astudillo-Defru, Stéphane Udry, Xavier Bonfils, Francesco Pepe, Pedro Figueira, A. Leleu, Philippe Robutel, Alexandre C. M. Correia, Jorge Lillo-Box, S. G. Sousa, C. Lovis, Magali Deleuil, O. Mousis, Jose-Manuel Almenara, Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Instituto de Astrofísica e Ciências do Espaço (IASTRO), Center for Space and Habitability (CSH), University of Bern, Space Research and Planetary Sciences [Bern) (WP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], National Centre of Competence in Research PlanetS (NCCR PlanetS), Universität Bern [Bern]-Universität Bern [Bern]-Swiss National Science Foundation (SNSF), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Departamento de Física e Astronomia [Porto] (DFA/FCUP), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto-Universidade do Porto, Geneva Observatory, University of Geneva [Switzerland], Centro de Física da Universidade de Coimbra (CFisUC), Universidade de Coimbra [Coimbra], Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Departamento de Matemática y Fı́sica Aplicadas [Concepcion] (DMFA), Universidad Católica de la Santísima Concepción (UCSC), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Spanish StateResearch Agency (AEI) Projects No.ESP2017-87676-C5-1-R and No. MDM-2017-0737 Unidad de Excelencia 'María de Maeztu' – Centro de Astrobiología(INTA-CSIC). This work was supported by FCT – Fundação para a Ciênciae a Tecnologia through national funds and by FEDER through COM-PETE2020 – Programa Operacional Competitividade e Internacionalizaçãoby 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. N.A.-D. acknowledges thesupport of FONDECYT project 3180063. X.B. and J.M.A. acknowledge fundingfrom the European Research Council under the ERC Grant Agreement n. 337591-ExTrA. A.C. acknowledges support by CFisUC projects (UIDB/04564/2020and UIDP/04564/2020), ENGAGE SKA (POCI-01-0145-FEDER-022217), andPHOBOS (POCI-01-0145-FEDER-029932), funded by COMPETE 2020 andFCT, Portugal. J.P.F. is supported in the form of a work contract funded bynational funds through FCT with reference DL57/2016/CP1364/CT0005, European Project: 337591,EC:FP7:ERC,ERC-2013-StG,EXTRA(2014), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE)-Swiss National Science Foundation (SNSF), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Universidade do Porto = University of Porto-Universidade do Porto = University of Porto, Université de Genève = University of Geneva (UNIGE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Faria, J. [0000-0002-6728-244X], Correia, A. C. M. [0000-0002-8946-8579], Leleu, A. [0000-0003-2051-7974], Lillo Box, J. [0000-0003-3742-1987], Santos, N. [0000-0003-4422-2919], Agencia Estatal de Investigación (AEI), FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao, Comisión Nacional de Investigación Científica y Tecnológica (CONICYT), European Research Council (ERC), ENGAGE SKA, PHOBOS, Portuguese Foundation for Science and Technology, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Fundacao para a Ciencia e a Tecnologia (FCT), Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT), and European Commission (EC)
- Subjects
010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Context (language use) ,Astrophysics ,polarimetric [Techniques] ,01 natural sciences ,Photometry (optics) ,planets and satellites: terrestrial planets ,Planet ,0103 physical sciences ,techniques: radial velocities ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,[PHYS]Physics [physics] ,radial velocities [Techniques] ,planets and satellites: composition ,Astronomy and Astrophysics ,Planetary system ,Orbital period ,interiors [Planets and satellites] ,Exoplanet ,planets and satellites: interiors ,planets and satellites: individual: LHS1140 ,Radial velocity ,techniques: polarimetric ,13. Climate action ,Space and Planetary Science ,terrestrial planets [Planets and satellites] ,composition [Planets and satellites] ,individual: LHS1140 [Planets and satellites] ,[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA] ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Circumstellar habitable zone ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Context. LHS 1140 is an M dwarf known to host two transiting planets at orbital periods of 3.77 and 24.7 days. They were detected with HARPS and Spitzer. The external planet (LHS 1140 b) is a rocky super-Earth that is located in the middle of the habitable zone of this low-mass star. All these properties place this system at the forefront of the habitable exoplanet exploration, and it therefore constitutes a relevant case for further astrobiological studies, including atmospheric observations. Aims. We further characterize this system by improving the physical and orbital properties of the known planets, search for additional planetary-mass components in the system, and explore the possibility of co-orbitals. Methods. We collected 113 new high-precision radial velocity observations with ESPRESSO over a 1.5-yr time span with an average photon-noise precision of 1.07 m s-1. We performed an extensive analysis of the HARPS and ESPRESSO datasets and also analyzed them together with the new TESS photometry. We analyzed the Bayesian evidence of several models with different numbers of planets and orbital configurations. Results. We significantly improve our knowledge of the properties of the known planets LHS 1140 b (Pb ∼ 24.7 days) and LHS 1140 c (Pc ∼ 3.77 days). We determine new masses with a precision of 6% for LHS 1140 b (6.48 ± 0.46 Mpdbl) and 9% for LHS 1140 c (mc = 1.78 ± 0.17 Mpdbl). This reduces the uncertainties relative to previously published values by half. Although both planets have Earth-like bulk compositions, the internal structure analysis suggests that LHS 1140 b might be iron-enriched and LHS 1140 c might be a true Earth twin. In both cases, the water content is compatible to a maximum fraction of 10-12% in mass, which is equivalent to a deep ocean layer of 779 ± 650 km for the habitable-zone planet LHS 1140 b. Our results also provide evidence for a new planet candidate in the system (md = 4.8 ± 1.1Mpdbl) on a 78.9-day orbital period, which is detected through three independent methods. The analysis also allows us to discard other planets above 0.5 Mpdbl for periods shorter than 10 days and above 2 Mpdbl for periods up to one year. Finally, our co-orbital analysis discards co-orbital planets in the tadpole and horseshoe configurations of LHS 1140 b down to 1 Mpdbl with a 95% confidence level (twice better than with the previous HARPS dataset). Indications for a possible co-orbital signal in LHS 1140 c are detected in both radial velocity (alternatively explained by a high eccentricity) and photometric data (alternatively explained by systematics), however. Conclusions. The new precise measurements of the planet properties of the two transiting planets in LHS 1140 as well as the detection of the planet candidate LHS 1140 d make this system a key target for atmospheric studies of rocky worlds at different stellar irradiations., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)
- Published
- 2020