A possible misaligned orbit for the young planet AU Mic c

Yu, H; Garai, Z; Cretignier, M; Szabó, Gy M; Aigrain, S; Gandolfi, D; Bryant, E M; Correia, A C M; Klein, B; Brandeker, A; Owen, J E; Günther, M N; Winn, J N; Heitzmann, A; Cegla, H M; Wilson, T G; Gill, S; Kriskovics, L; Barragán, O; Boldog, A; Nielsen, L D; Billot, N; Lafarga, M; Meech, A; Alibert, Y; Alonso, R; Bárczy, T; Barrado, D; Barros, S C C; Baumjohann, W; Bayliss, D; Benz, W; Bergomi, M; Borsato, L; Broeg, C; Cameron, A Collier; Csizmadia, Sz; Cubillos, P E; Davies, M B; Deleuil, M; Deline, A; Demangeon, O D S; Demory, B.-O; Derekas, A; Doyle, L; Edwards, B; Egger, J A; Ehrenreich, D; Erikson, A; Fortier, A; Fossati, L; Fridlund, M; Gazeas, K; Gillon, M; Güdel, M; Helling, Ch; Isaak, K G; Kiss, L L; Korth, J; Lam, K W F; Laskar, J; Etangs, A Lecavelier des; Lendl, M; Magrin, D; Maxted, P F L; McCormac, J; Merín, B; Mordasini, C; Nascimbeni, V; O’Brien, S M; Olofsson, G; Ottensamer, R; Pagano, I; Pallé, E; Peter, G; Piazza, D; Piotto, G; Pollacco, D; Queloz, D; Ragazzoni, R; Rando, N; Rauer, H; Ribas, I; Santos, N C; Scandariato, G; Ségransan, D; Simon, A E; Smith, A M S; Sousa, S G; Southworth, R; Stalport, M; Steinberger, M; Sulis, S; Udry, S; Ulmer, B; Ulmer-Moll, S; Van Grootel, V; Venturini, J; Villaver, E; Walton, N A; Wheatley, P J

doi:10.1093/mnras/stae2655

A possible misaligned orbit for the young planet AU Mic c

Yu, H; Garai, Z; Cretignier, M; Szabó, Gy M; Aigrain, S; Gandolfi, D; Bryant, E M; Correia, A C M; Klein, B; Brandeker, A; Owen, J E; Günther, M N; Winn, J N; Heitzmann, A; Cegla, H M; Wilson, T G; Gill, S; Kriskovics, L; Barragán, O; Boldog, A; Nielsen, L D; Billot, N; Lafarga, M; Meech, A; Alibert, Y; Alonso, R; Bárczy, T; Barrado, D; Barros, S C C; Baumjohann, W; Bayliss, D; Benz, W; Bergomi, M; Borsato, L; Broeg, C; Cameron, A Collier; Csizmadia, Sz; Cubillos, P E; Davies, M B; Deleuil, M; Deline, A; Demangeon, O D S; Demory, B.-O; Derekas, A; Doyle, L; Edwards, B; Egger, J A; Ehrenreich, D; Erikson, A; Fortier, A; Fossati, L; Fridlund, M; Gazeas, K; Gillon, M; Güdel, M; Helling, Ch; Isaak, K G; Kiss, L L; Korth, J; Lam, K W F; Laskar, J; Etangs, A Lecavelier des; Lendl, M; Magrin, D; Maxted, P F L; McCormac, J; Merín, B; Mordasini, C; Nascimbeni, V; O’Brien, S M; Olofsson, G; Ottensamer, R; Pagano, I; Pallé, E; Peter, G; Piazza, D; Piotto, G; Pollacco, D; Queloz, D; Ragazzoni, R;...

Authors

H Yu

Z Garai

M Cretignier

Gy M Szabó

S Aigrain

D Gandolfi

E M Bryant

A C M Correia

B Klein

A Brandeker

J E Owen

M N Günther

J N Winn

A Heitzmann

H M Cegla

T G Wilson

S Gill

L Kriskovics

O Barragán

A Boldog

L D Nielsen

N Billot

M Lafarga

A Meech

Y Alibert

R Alonso

T Bárczy

D Barrado

S C C Barros

W Baumjohann

D Bayliss

W Benz

M Bergomi

L Borsato

C Broeg

A Collier Cameron

Sz Csizmadia

P E Cubillos

M B Davies

M Deleuil

A Deline

O D S Demangeon

B.-O Demory

A Derekas

L Doyle

B Edwards

J A Egger

D Ehrenreich

A Erikson

A Fortier

L Fossati

M Fridlund

K Gazeas

M Gillon

M Güdel

Ch Helling

K G Isaak

L L Kiss

J Korth

K W F Lam

J Laskar

A Lecavelier des Etangs

M Lendl

D Magrin

Pierre Maxted p.maxted@keele.ac.uk

J McCormac

B Merín

C Mordasini

V Nascimbeni

S M O’Brien

G Olofsson

R Ottensamer

I Pagano

E Pallé

G Peter

D Piazza

G Piotto

D Pollacco

D Queloz

R Ragazzoni

N Rando

H Rauer

I Ribas

N C Santos

G Scandariato

D Ségransan

A E Simon

A M S Smith

S G Sousa

R Southworth

M Stalport

M Steinberger

S Sulis

S Udry

B Ulmer

S Ulmer-Moll

V Van Grootel

J Venturini

E Villaver

N A Walton

P J Wheatley

Abstract

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 VLT/ESPRESSO, CHEOPS, and 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 $\lambda _c=67.8_{-49.0}^{+31.7}$ degrees (1-σ). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b ($\lambda _b=-2.96_{-10.30}^{+10.44}$), 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.

Citation

Yu, H., Garai, Z., Cretignier, M., Szabó, G. M., Aigrain, S., Gandolfi, D., …Wheatley, P. J. (in press). A possible misaligned orbit for the young planet AU Mic c. Monthly Notices of the Royal Astronomical Society, 18. https://doi.org/10.1093/mnras/stae2655

Journal Article Type	Article
Acceptance Date	Nov 27, 2024
Online Publication Date	Nov 27, 2024
Deposit Date	Dec 20, 2024
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Pages	18
DOI	https://doi.org/10.1093/mnras/stae2655
Keywords	techniques: radial velocities, techniques: photometric, stars: activity, stars: individual: AU Microscopii, planets and satellites: dynamical evolution and stability, planets and satellites: formation
Public URL	https://keele-repository.worktribe.com/output/1015932