Three planets transiting the evolved star EPIC 249893012: a hot 8.8-Mearth super-Earth and two warm 14.7 and 10.2-Mearth sub-Neptunes
Artikel i vetenskaplig tidskrift, 2020
We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star (M⋆ = 1.05 ± 0.05 M☉, R⋆ = 1.71 ± 0.04 R☉, Teff = 5430 ± 85 K). The star is just leaving the main sequence. We combined K2 photometry with IRCS adaptive-optics imaging and HARPS, HARPS-N, and CARMENES high-precision radial velocity measurements to confirm the planetary system, determine the stellar parameters, and measure radii, masses, and densities of the three planets. With an orbital period of 3.5949-0.0007+0.0007days, a mass of 8.75-1.08+1.09 M⊕, and a radius of 1.95-0.08+0.09 R⊕, the inner planet b is compatible with nickel-iron core and a silicate mantle (ρb = 6.39-1.04+1.19 g cm-3). Planets c and d with orbital periods of 15.624-0.001+0.001 and 35.747-0.005+0.005 days, respectively, have masses and radii of 14.67-1.89+1,84 M⊕ and 3.67-0.14+0.17 R⊕ and 10.18-2.42+2.46 M⊕ and 3.94-0.12+0.13 R⊕, respectively, yielding a mean density of 1.62-0.29+0.30 and 0.91-0.23+0.25 g cm-3, respectively. The radius of planet b lies in the transition region between rocky and gaseous planets, but its density is consistent with a rocky composition. Its semimajor axis and the corresponding photoevaporation levels to which the planet has been exposed might explain its measured density today. In contrast, the densities and semimajor axes of planets c and d suggest a very thick atmosphere. The singularity of this system, which orbits a slightly evolved star that is just leaving the main sequence, makes it a good candidate for a deeper study from a dynamical point of view.
techniques: radial velocities
planets and satellites: fundamental parameters
planets and satellites: detection
techniques: photometric
planetary systems
Författare
D. Hidalgo
Instituto de Astrofísica de Canarias
Universidad de la Laguna
E. Palle
Instituto de Astrofísica de Canarias
Universidad de la Laguna
D. Gandolfi
Universita degli Studi di Torino
Malcolm Fridlund
Universiteit Leiden
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Grzegorz Nowak
Universidad de la Laguna
R. Luque
Universidad de la Laguna
Instituto de Astrofísica de Canarias
T. Hirano
Tokyo Institute of Technology
A. B. Justesen
National Astronomical Observatory of Japan
W. D. Cochran
The University of Texas at Austin
O. Barragan
University of Oxford
Universita degli Studi di Torino
L Spina
Monash University
F. Rodler
European Southern Observatory Santiago
S. Albrecht
Aarhus Universitet
D. Anderson
The University of Warwick
P. J. Amado
Consejo Superior de Investigaciones Científicas (CSIC)
E. Bryant
The University of Warwick
Consejo Superior de Investigaciones Científicas (CSIC)
J. A. Caballero
Consejo Superior de Investigaciones Científicas (CSIC)
Juan Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
F. Dai
Massachusetts Institute of Technology (MIT)
Princeton University
J. de Leon
National Institutes of Natural Sciences
Hans Deeg
Universidad de la Laguna
Instituto de Astrofísica de Canarias
Ph. Eigmuller
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
M. Endl
The University of Texas at Austin
A. Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
M. Esposito
Thüringer Landessternwarte Tautenburg
P. Figueira
Universidade do Porto
European Southern Observatory Santiago
Iskra Georgieva
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
S. Grziwa
Universität zu Köln
E. Guenther
Thüringer Landessternwarte Tautenburg
Artie P. Hatzes
Thüringer Landessternwarte Tautenburg
M. Hjorth
Aarhus Universitet
H. J. Hoeijmakers
Universität Bern
Université de Genève
P. Kabath
Czech Academy of Sciences
Judith Korth
Universität zu Köln
M. Kuzuhara
National Institutes of Natural Sciences
M. Lafarga
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Monash University
M. Lampon
Consejo Superior de Investigaciones Científicas (CSIC)
I.C. Leão
Universidade Federal do Rio Grande do Sul (UFRGS)
J. Livingston
University of Tokyo
S. Mathur
Instituto de Astrofísica de Canarias
Universidad de la Laguna
Pilar Montanes Rodriguez
Universidad de la Laguna
Instituto de Astrofísica de Canarias
J. C. Morales
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
Consejo Superior de Investigaciones Científicas (CSIC)
F. Murgas
Instituto de Astrofísica de Canarias
Universidad de la Laguna
E. Nagel
Hamburger Sternwarte
N. Narita
Japan Science and Technology Agency
Instituto de Astrofísica de Canarias
National Institutes of Natural Sciences
L. D. Nielsen
Université de Genève
M. Patzold
Universität zu Köln
Carina Persson
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
J. Prieto-Arranz
Universidad de la Laguna
Instituto de Astrofísica de Canarias
A. Quirrenbach
Universität Heidelberg
H. Rauer
Freie Universität Berlin
Technische Universität Berlin
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
S. Redfield
Wesleyan University
A. Reiners
Georg-August-Universität Göttingen
I Ribas
Consejo Superior de Investigaciones Científicas (CSIC)
Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)
A. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
J. Subjak
Univerzita Karlova
Czech Academy of Sciences
V. Van Eylen
University College London (UCL)
P. A. Wilson
The University of Warwick
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 636 A89Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två missioner
Rymdstyrelsen (174/18), 2017-01-01 -- 2022-12-31.
Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
Fundament
Grundläggande vetenskaper
DOI
10.1051/0004-6361/201937080