An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345
Artikel i vetenskaplig tidskrift, 2025

A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential vital link needs testing by characterizing exoplanets around chemically-diverse stars. We present the discovery of two planets orbiting the metal-poor, kinematic thick-disc K-dwarf TOI-2345. TOI-2345 b is a super-Earth with a period of 1.05 d and TOI-2345 c is a sub-Neptune with a period of 21 d. In addition to the target being observed in four TESS sectors, we obtained five CHEOPS visits and 26 radial velocities from HARPS. By conducting a joint analysis of all the data, we find TOI-2345 b to have a radius of 1.504+0.047-0.044 R⊕ and a mass of 3.49 ± 0.85 M⊕; and TOI-2345 c to have a radius of 2.451+0.045-0.046 R⊕ and a mass of 7.27+2.27-2.45 M⊕. To explore chemical links between these planets and their host star, we model their interior structures newly accounting for devolatized stellar abundances. TOI-2345 adds to the limited sample of well-characterized planetary systems around thick disc stars. This system challenges theories of formation and populations of planets around thick disc stars with its Ultra-Short Period super-Earth and the wide period distribution of these two planets spanning the radius valley.

planets and satellites: detection

planets and satellites: individual: TOI-2345 b & c

techniques: photometric - techniques: radial velocities

planets and satellites: interiors

stars: individual: TOI-2345

Författare

Yoshi Eschen

The University of Warwick

T.G. Wilson

The University of Warwick

A. Bonfanti

Institut fur Weltraumforschung

Carina Persson

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

S.G. Sousa

Universidade do Porto

M. Lendl

Université de Genève

A. Heitzmann

Université de Genève

A.E. Simon

Universität Bern

Physics Institute

G. Olofsson

Stockholms universitet

A. Castro-González

Université de Genève

J. A. Egger

Physics Institute

L. Fossati

Institut fur Weltraumforschung

A. J. Mustill

Lunds universitet

H. P. Osborn

Eidgenössische Technische Hochschule Zürich (ETH)

Universität Bern

Hugo G. Vivien

Laboratoire d'Astrophysique de Marseille

Y. Alibert

Physics Institute

Universität Bern

R. Alonso

Universidad de la Laguna

Instituto de Astrofísica de Canarias

T. Bárczy

Admatis

D. Barrado

Europeiska rymdorganisationen (ESA)

S.C.C. Barros

Universidade do Porto

W. Baumjohann

Institut fur Weltraumforschung

W. Benz

Physics Institute

Universität Bern

N. Billot

Université de Genève

L. Borsato

Istituto nazionale di astrofisica (INAF)

A. Brandeker

Stockholms universitet

C. Broeg

Physics Institute

Universität Bern

M. Buder

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

D. A. Caldwell

National Aeronautics and Space Administration (NASA)

SETI Institute

A. Collier Cameron

University of St Andrews

A. Correia

Universidade de Coimbra

Szilard Csizmadia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

P. E. Cubillos

Institut fur Weltraumforschung

Istituto nazionale di astrofisica (INAF)

Melvyn B. Davies

Lunds universitet

M. Deleuil

Laboratoire d'Astrophysique de Marseille

A. Deline

Université de Genève

O. Demangeon

Universidade do Porto

B.O. Demory

Physics Institute

Universität Bern

A. Derekas

Eötvös Loránd University (ELTE)

Billy Edwards

Netherlands Institute for Space Research (SRON)

D. Ehrenreich

Université de Genève

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Farinato

Istituto nazionale di astrofisica (INAF)

A. Fortier

Physics Institute

Universität Bern

Malcolm Fridlund

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

Universiteit Leiden

D. Gandolfi

Universita degli Studi di Torino

K. Gazeas

University of Athens

Michaël Gillon

Universite de Liège

Robert Goeke

Massachusetts Institute of Technology (MIT)

M. Gudel

Universität Wien

Maximilian N. Günther

Europeiska rymdorganisationen (ESA)

J. Hasiba

Institut fur Weltraumforschung

Ch. Helling

Technische Universität Graz

Institut fur Weltraumforschung

K. Isaak

Europeiska rymdorganisationen (ESA)

Jon M. Jenkins

National Aeronautics and Space Administration (NASA)

Tatiana Keller

Universität Bern

Physics Institute

L. L. Kiss

Eötvös Loránd University (ELTE)

Research Centre For Astronomy and Earth Sciences

D. Kitzmann

Universität Bern

Physics Institute

Judith Korth

Université de Genève

K. W.F. Lam

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

J. Laskar

Observatoire de Paris

A. L. des Etangs

Institut d 'Astrophysique de Paris

A. Leleu

Physics Institute

Université de Genève

D. Magrin

Istituto nazionale di astrofisica (INAF)

P. Maxted

Keele University

Bruno Merín

Europeiska rymdorganisationen (ESA)

C. Mordasini

Universität Bern

Physics Institute

Valerio Nascimbeni

Istituto nazionale di astrofisica (INAF)

R. Ottensamer

Universität Wien

I. Pagano

Istituto nazionale di astrofisica (INAF)

Enric Palle

Universidad de la Laguna

Instituto de Astrofísica de Canarias

G. Peter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

D. Piazza

Universität Bern

Giampaolo P. Piotto

Università di Padova

Istituto nazionale di astrofisica (INAF)

Don L. Pollacco

The University of Warwick

D. Queloz

University of Cambridge

Eidgenössische Technische Hochschule Zürich (ETH)

Roberto Ragazzoni

Università di Padova

Istituto nazionale di astrofisica (INAF)

N. Rando

Europeiska rymdorganisationen (ESA)

F. Ratti

Europeiska rymdorganisationen (ESA)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Freie Universität Berlin

I. Ribas

Consejo Superior de Investigaciones Científicas (CSIC)

Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

N. C. Santos

Universidade do Porto

Gaetano Scandariato

Istituto nazionale di astrofisica (INAF)

D. Segransan

Université de Genève

Avi Shporer

Massachusetts Institute of Technology (MIT)

A. M.S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

M. Stalport

Universite de Liège

S. Sulis

Laboratoire d'Astrophysique de Marseille

G.M. Szabó

Eötvös Loránd University (ELTE)

Hungarian Research Network

S. Udry

Université de Genève

S. Ulmer-Moll

Universiteit Leiden

Universite de Liège

V. Van Grootel

Universite de Liège

J. Venturini

Université de Genève

E. Villaver

Universidad de la Laguna

Instituto de Astrofísica de Canarias

N. A. Walton

University of Cambridge

David Watanabe

Planetary Discoveries

S. Wolf

Physics Institute

C. Ziegler

Stephen F. Austin State University

Monthly Notices of the Royal Astronomical Society

00358711 (ISSN) 13652966 (eISSN)

Vol. 544 2 2614-2636

Ämneskategorier (SSIF 2025)

Astronomi, astrofysik och kosmologi

DOI

10.1093/mnras/staf1806

Mer information

Senast uppdaterat

2026-01-07