A possible misaligned orbit for the young planet AU Mic c
Artikel i vetenskaplig tidskrift, 2025

The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter–McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory’s (ESO’s) Very Large Telescope (VLT)/Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), CHaracterising ExOPlanet Satellite (CHEOPS), and Next-Generation Transit Survey (NGTS). After correcting for flares and for the magnetic activity of the host star, and accounting for transit-timing variations, we find the sky-projected spin–orbit angle of planet c to be in the range λc = 67.8+31.7-49.0 degrees (1σ). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b (λb = −2.96 +10.44-10.30), and the equatorial plane of the host star, and discuss scenarios that could explain both this and the planet’s high density, including secular interactions with other bodies in the system or a giant impact. We note that a significantly misaligned orbit for planet c is in some degree of tension with the dynamical stability of the system, and with the fact that we see both planets in transit, though these arguments alone do not preclude such an orbit. Further observations would be highly desirable to constrain the spin–orbit angle of planet c more precisely.

techniques: photometric

stars: activity

techniques: radial velocities

stars: individual: AU Microscopii

planets and satellites: formation

planets and satellites: dynamical evolution and stability

Författare

H. Yu

University of Oxford

Z. Garai

HUN-REN-ELTE Exoplanet Research Group

M. Cretignier

University of Oxford

G.M. Szabó

HUN-REN-ELTE Exoplanet Research Group

S. Aigrain

University of Oxford

D. Gandolfi

Universita degli Studi di Torino

E. Bryant

University College London (UCL)

A. Correia

Centre for Physics of the University of Coimbra

B. Klein

University of Oxford

A. Brandeker

Stockholms universitet

James E. Owen

Imperial College London

Maximilian N. Günther

European Space Research and Technology Centre (ESA ESTEC)

J. N. Winn

Princeton University

A. Heitzmann

Université de Genève

H. M. Cegla

Université de Genève

T.G. Wilson

The University of Warwick

S. Gill

The University of Warwick

L. Kriskovics

Magyar Tudomanyos Akademia

O. Barragán

University of Oxford

Boldog

HUN-REN-ELTE Exoplanet Research Group

L. D. Nielsen

Ludwig-Maximilians-Universität München (LMU)

N. Billot

Université de Genève

Marina Lafarga

The University of Warwick

Annabella Meech

University of Oxford

Y. Alibert

Universität Bern

R. Alonso

Instituto de Astrofísica de Canarias

T. Bárczy

Admatis

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

W. Benz

Universität Bern

M. Bergomi

Istituto nazionale di astrofisica (INAF)

L. Borsato

Istituto nazionale di astrofisica (INAF)

C. Broeg

Universität Bern

A. Collier Cameron

University of St Andrews

Szilard Csizmadia

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

P. E. Cubillos

Institut fur Weltraumforschung

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

Universität Bern

A. Derekas

Eötvös Loránd University (ELTE)

L. Doyle

The University of Warwick

Billy Edwards

Netherlands Institute for Space Research (SRON)

J. A. Egger

Physics Institute

D. Ehrenreich

Université de Genève

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

A. Fortier

Universität Bern

L. Fossati

Institut fur Weltraumforschung

Malcolm Fridlund

Universiteit Leiden

K. Gazeas

University of Athens

Michaël Gillon

Universite de Liège

M. Gudel

Universität Wien

Ch. Helling

Institut fur Weltraumforschung

K. Isaak

European Space Research and Technology Centre (ESA ESTEC)

L. L. Kiss

Magyar Tudomanyos Akademia

Judith Korth

Lunds universitet

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

M. Lendl

Université de Genève

D. Magrin

Istituto nazionale di astrofisica (INAF)

P. Maxted

Keele University

J. McCormac

The University of Warwick

Bruno Merín

European Space Astronomy Centre (ESAC)

C. Mordasini

Universität Bern

Valerio Nascimbeni

Istituto nazionale di astrofisica (INAF)

S.M. O’Brien

Queen's University Belfast

G. Olofsson

Stockholms universitet

R. Ottensamer

Universität Wien

I. Pagano

Istituto nazionale di astrofisica (INAF)

Enric Palle

Instituto de Astrofísica de Canarias

G. Peter

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

D. Piazza

Universität Bern

Giampaolo P. Piotto

Istituto nazionale di astrofisica (INAF)

Don L. Pollacco

The University of Warwick

D. Queloz

Eidgenössische Technische Hochschule Zürich (ETH)

Roberto Ragazzoni

Istituto nazionale di astrofisica (INAF)

N. Rando

European Space Research and Technology Centre (ESA ESTEC)

H. Rauer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

I. Ribas

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

N. C. Santos

Universidade do Porto

Gaetano Scandariato

Istituto nazionale di astrofisica (INAF)

D. Segransan

Université de Genève

A.E. Simon

Universität Bern

A. M.S. Smith

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

S.G. Sousa

Universidade do Porto

R. Southworth

European Space Operations Centre

M. Stalport

Universite de Liège

M. Steinberger

Institut fur Weltraumforschung

S. Sulis

Laboratoire d'Astrophysique de Marseille

S. Udry

Université de Genève

B. Ulmer

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

S. Ulmer-Moll

Université de Genève

V. Van Grootel

Universite de Liège

J. Venturini

Université de Genève

E. Villaver

Instituto de Astrofísica de Canarias

N. A. Walton

University of Cambridge

P. J. Wheatley

The University of Warwick

Monthly Notices of the Royal Astronomical Society

00358711 (ISSN) 13652966 (eISSN)

Vol. 536 3 2046-2063

Ämneskategorier (SSIF 2025)

Astronomi, astrofysik och kosmologi

DOI

10.1093/mnras/stae2655

Mer information

Senast uppdaterat

2025-02-03