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.

planetary systems

techniques: photometric

techniques: radial velocities

planets and satellites: fundamental parameters

planets and satellites: detection

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, Galaktisk astrofysik

Grzegorz Nowak

Universidad de la Laguna

R. Luque

Universidad de la Laguna

Instituto Astrofisico 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

Universita degli Studi di Torino

University of Oxford

L Spina

Monash University

F. Rodler

European Southern Observatory Santiago

S. Albrecht

Aarhus Universitet

D. Anderson

The University of Warwick

P. J. Amado

CSIC - Instituto de Astrofísica de Andalucía (IAA)

E. Bryant

The University of Warwick

CSIC - Instituto de Astrofísica de Andalucía (IAA)

J. A. Caballero

Centro de Astrobiología (INTA-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 Astrofisico de Canarias

Ph. Eigmuller

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Technische Universität Berlin

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, Galaktisk astrofysik

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

Universite de Geneve

P. Kabath

Astronomical Institute, Academy of Sciences of the Czech Republic v.v.i.

J. Korth

Universität zu Köln

M. Kuzuhara

National Institutes of Natural Sciences

M. Lafarga

Institut d'Estudis Espacials de Catalunya (IEEC)

Monash University

M. Lampon

CSIC - Instituto de Astrofísica de Andalucía (IAA)

I.C. Leão

Universidade Federal do Rio Grande do Sul (UFRGS)

J. Livingston

University of Tokyo

S. Mathur

Universidad de la Laguna

Instituto Astrofisico de Canarias

Pilar Montanes Rodriguez

Instituto Astrofisico de Canarias

Universidad de la Laguna

J. C. Morales

Institut de Ciències de l'Espai (ICE) - CSIC

Institut d'Estudis Espacials de Catalunya (IEEC)

F. Murgas

Universidad de la Laguna

Instituto Astrofisico de Canarias

E. Nagel

Hamburger Sternwarte

N. Narita

Instituto de Astrofísica de Canarias

National Institutes of Natural Sciences

Japan Science and Technology Agency

L. D. Nielsen

Universite de Geneve

M. Patzold

Universität zu Köln

Carina Persson

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

J. Prieto-Arranz

Instituto Astrofisico de Canarias

Universidad de la Laguna

A. Quirrenbach

Universität Heidelberg

H. Rauer

Technische Universität Berlin

Freie Universität Berlin

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

S. Redfield

Wesleyan University

A. Reiners

Georg-August-Universität Göttingen

I Ribas

Institut d'Estudis Espacials de Catalunya (IEEC)

Institut de Ciències de l'Espai (ICE) - CSIC

A. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Subjak

Czech Academy of Sciences

Univerzita Karlova v Praze

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 A89

Exoplaneter från rymden - CHEOPS och PLATO

Rymdstyrelsen, 2017-01-01 -- 2022-12-31.

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

DOI

10.1051/0004-6361/201937080

Mer information

Senast uppdaterat

2020-09-23