Six transiting planets and a chain of Laplace resonances in TOI-178
Artikel i vetenskaplig tidskrift, 2021

Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the fragility of their orbital configuration ensures that no significant scattering or collisional event has taken place since the earliest formation phase when the parent protoplanetary disc was still present. In this context, TOI-178 has been the subject of particular attention since the first TESS observations hinted at the possible presence of a near 2:3:3 resonant chain. Here we report the results of observations from CHEOPS, ESPRESSO, NGTS, and SPECULOOS with the aim of deciphering the peculiar orbital architecture of the system. We show that TOI-178 harbours at least six planets in the super-Earth to mini-Neptune regimes, with radii ranging from 1.152 to 2.87 Earth radii and periods of 1.91, 3.24, 6.56, 9.96, 15.23, and 20.71 days. All planets but the innermost one form a 2:4:6:9:12 chain of Laplace resonances, and the planetary densities show important variations from planet to planet, jumping from 1.02 to 0.177 times the Earth's density between planets c and d. Using Bayesian interior structure retrieval models, we show that the amount of gas in the planets does not vary in a monotonous way, contrary to what one would expect from simple formation and evolution models and unlike other known systems in a chain of Laplace resonances. The brightness of TOI-178 (H = 8.76 mag, J = 9.37 mag, V = 11.95 mag) allows for a precise characterisation of its orbital architecture as well as of the physical nature of the six presently known transiting planets it harbours. The peculiar orbital configuration and the diversity in average density among the planets in the system will enable the study of interior planetary structures and atmospheric evolution, providing important clues on the formation of super-Earths and mini-Neptunes. -0.070 -0.13 -0.23 -0.061 +0.073 +0.14 +0.28 +0.055

Planets and satellites: Detection

Celestial mechanics

Planets and satellites: Dynamical evolution and stability

Techniques: Spectroscopic

Techniques: Photometric

Författare

A. Leleu

Université de Genève

Y. Alibert

Universität Bern

N.C. Hara

Université de Genève

M.J. Hooton

Universität Bern

T.G. Wilson

University of St Andrews

P. Robutel

Observatoire de Paris

J. B. Delisle

Université de Genève

J. Laskar

Observatoire de Paris

S. Hoyer

Laboratoire d'Astrophysique de Marseille

C. Lovis

Université de Genève

E. Bryant

The University of Warwick

E. Ducrot

Universite de Liège

J. Cabrera

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

L. Delrez

Université de Genève

J.S. Acton

University Of Leicester

V. Adibekyan

Universidade do Porto

R. Allart

Université de Genève

C. Allende Prieto

Instituto Astrofisico de Canarias

R. Alonso

Instituto Astrofisico de Canarias

D. Alves

Camino El Observatorio 1515

D.R. Anderson

The University of Warwick

D. Angerhausen

Eidgenössische Technische Hochschule Zürich (ETH)

G. Anglada Escude´

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

J. Asquier

European Space Research and Technology Centre (ESA ESTEC)

D. Barrado

European Space Astronomy Centre (ESAC)

S.C.C. Barros

Universidade do Porto

W. Baumjohann

Institut fur Weltraumforschung

D. Bayliss

The University of Warwick

M. Beck

Université de Genève

T. Beck

Universität Bern

A. Bekkelien

Université de Genève

W. Benz

Universität Bern

N. Billot

Université de Genève

A. Bonfanti

Institut fur Weltraumforschung

X. Bonfils

Université Grenoble Alpes

F. Bouchy

Université de Genève

V. Bourrier

Université de Genève

G. Boue´

Observatoire de Paris

A. Brandeker

Stockholms universitet

C. Broeg

Universität Bern

M. Buder

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

A. Burdanov

Universite de Liège

Matt Burleigh

University Of Leicester

T. Bárczy

Admatis

A.C. Cameron

University of St Andrews

S. Chamberlain

University Of Leicester

S. Charnoz

Université Paris Descartes

B. Cooke

The University of Warwick

C. Corral Van Damme

European Space Research and Technology Centre (ESA ESTEC)

A.C.M. Correia

Observatoire de Paris

S. Cristiani

Osservatorio Astronomico di Trieste

Mario Damasso

Istituto nazionale di astrofisica (INAF)

Melvyn B. Davies

Lunds universitet

M. Deleuil

Laboratoire d'Astrophysique de Marseille

O. Demangeon

Universidade do Porto

B.O. Demory

Center for Space and Habitability

P. Di Marcantonio

Osservatorio Astronomico di Trieste

G. Di Persio

Istituto nazionale di astrofisica (INAF)

X. Dumusque

Université de Genève

D. Ehrenreich

Université de Genève

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

P. Figueira

Universidade do Porto

A. Fortier

Universität Bern

L. Fossati

Institut fur Weltraumforschung

Malcolm Fridlund

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

Universiteit Leiden

D. Futyan

Université de Genève

D. Gandolfi

Universita degli Studi di Torino

A. Garcia´ Muno&tild;z

Technische Universität Berlin

L.J. Garcia

Universite de Liège

S. Gill

The University of Warwick

E. Gillen

Queen Mary University of London

Michaël Gillon

Universite de Liège

M.R. Goad

University Of Leicester

J.I. Gonza´lez Herna´ndez

Instituto Astrofisico de Canarias

M. Guedel

Universität Wien

M.N. Gu¨nther

Massachusetts Institute of Technology (MIT)

J. Haldemann

Universität Bern

B. Henderson

University Of Leicester

Kevin Heng

Center for Space and Habitability

A.E. Hogan

University Of Leicester

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

Emmanuel Jehin

Universite de Liège

J.S. Jenkins

Universidad de Chile (UCH)

A. Jorda´n

Universidad Adolfo Ibanez

L. Kiss

Magyar Tudomanyos Akademia

M. H. Kristiansen

Brorfelde Observatory

K. W.F. Lam

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

B. Lavie

Université de Genève

A. L. des Etangs

Institut d 'Astrophysique de Paris

M. Lendl

Université de Genève

J. Lillo-Box

European Space Astronomy Centre (ESAC)

G. Lo Curto

European Southern Observatory Santiago

D. Magrin

Osservatorio Astronomico di Padova

C.J.A.P. Martins

Universidade do Porto

P. Maxted

Keele University

J. McCormac

The University of Warwick

A. Mehner

European Southern Observatory Santiago

G. Micela

Istituto nazionale di astrofisica (INAF)

P. Molaro

Osservatorio Astronomico di Trieste

M. Moyano

Universidad Catolica del Norte

C.A. Murray

Department of Physics

Valerio Nascimbeni

Osservatorio Astronomico di Padova

N.J. Nunes

Universidade de Lisboa

G. Olofsson

Stockholms universitet

H. P. Osborn

Center for Space and Habitability

M. Oshagh

Instituto Astrofisico de Canarias

R. Ottensamer

Universität Wien

I. Pagano

Osservatorio Astrofisico di Catania

E. Palle

Instituto Astrofisico de Canarias

P.P. Pedersen

Department of Physics

Francesco Pepe

Université de Genève

Carina Persson

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

G. Peter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Giampaolo P. Piotto

Osservatorio Astronomico di Padova

G. Polenta

ASI

Don L. Pollacco

The University of Warwick

E. Poretti

INAF (Telescopio Nazionale Galileo)

Francisco J. Pozuelos

Universite de Liège

D. Queloz

Université de Genève

Roberto Ragazzoni

Osservatorio Astronomico di Padova

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

F. Ratti

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

L. Raynard

University Of Leicester

R. Rebolo

Instituto Astrofisico de Canarias

C. Reimers

Universität Wien

I. Ribas

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

N. C. Santos

Universidade do Porto

Gaetano Scandariato

Osservatorio Astrofisico di Catania

J. Schneider

Observatoire de Paris

D. Sebastian

University of Birmingham

M. Sestovic

Center for Space and Habitability

A.E. Simon

Universität Bern

Alexis M. S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

S.G. Sousa

Universidade do Porto

A. Sozzetti

Istituto nazionale di astrofisica (INAF)

Manfred B. Steller

Institut fur Weltraumforschung

A. Sua´rez Mascareno&tild;

Instituto Astrofisico de Canarias

G.M. Szabó

Eötvös Loránd University (ELTE)

D. Segransan

Université de Genève

Nicolas Thomas

Universität Bern

S. Thompson

Department of Physics

R.H. Tilbrook

University Of Leicester

Amaury Triaud

University of Birmingham

O. Turner

Université de Genève

S. Udry

Université de Genève

V. Van Grootel

Universite de Liège

H. Venus

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

F. Verrecchia

ASI

José I. Vines

Camino El Observatorio 1515

N. A. Walton

University of Cambridge

R.G. West

The University of Warwick

P.J. Wheatley

The University of Warwick

D. Wolter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Zapatero-Osorio

Centro de Astrobiologia (CAB)

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 649 A26

Förlängning: Exoplanets from space -CHEOPS and PLATO ESA's next two projects (Phase 2)

Rymdstyrelsen (65/19), 2020-01-01 -- 2022-12-31.

Exoplaneter från rymden - CHEOPS och PLATO

Rymdstyrelsen (174/18), 2017-01-01 -- 2022-12-31.

Ämneskategorier

Astronomi, astrofysik och kosmologi

Annan fysik

Inbäddad systemteknik

DOI

10.1051/0004-6361/202039767

Mer information

Senast uppdaterat

2021-05-24