A possible misaligned orbit for the young planet AU Mic c

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 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 $\lambda _{\mathrm{c}}=67.8_{-49.0}^{+31.7}$ degrees (1$\sigma$). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b ($\lambda _{\mathrm{b}}=-2.96_{-10.30}^{+10.44}$), 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.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-11-27
DOI
https://doi.org/10.1093/mnras/stae2655
Citations
8
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
2.65

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article

A possible misaligned orbit for the young planet AU Mic c

T. Bárczy, Lauren Doyle, A. Collier Cameron, N. Billot et al.
8 citations
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
2.65
article

A possible misaligned orbit for the young planet AU Mic c

T. Bárczy, Lauren Doyle, A. Collier Cameron, N. Billot, Y. Alibert, A. M. S. Smith, J. McCormac, J. Laskar, Julie E. Owen, Ádám Boldog, W. Benz, Maximilian N. Günther, Z. Garai, S. Sulis, B. -O. Demory, Maria Bergomi, Richard Southworth, L. Borsato, M. Gillon, P. F. L. Maxted, D. Pollacco, Soléne Ulmer-Moll, V. Nascimbeni, M. Lendl, Baptiste Klein, Ε. Πάλλη, Annabella Meech, L. L. Kiss, D. Gandolfi, D. Queloz, A. C. M. Correia, Daniel Bayliss, C. Mordasini, A. E. Simon, G. Piotto, M. B. Davies, M Stalport, J. A. Egger, R. Alonso, G. Peter, Roberto Ragazzoni, Samuel Gill, L. Kriskovics, J. Korth, A. Fortier, A. Derekas, I. Ribas, K. W. F. Lam, K. G. Isaak, Haochuan Yu, Ch. Helling, S. Aigrain, P. J. Wheatley, Sean O'Brien, M. Cretignier, C. Broeg, A. Heitzmann, G. Scandariato, M Fridlund, Edward M. Bryant, D. Barrado, N. A. Walton, Louise D. Nielsen, A. Lecavelier des Étangs, Szilárd Csizmadia, W. Baumjohann, M. Lafarga, S. C. C. Barros, E. Villaver, N. C. Santos, Patricio E. Cubillos, Oscar Barragán, Demetrio Magrin, K. Gazeas, J. Venturini, G. Olofsson, M Deleuil, H. M. Cegla, L. Fossati, D. Ehrenreich, A. Deline, B Edwards, A. Brandeker, T. G. Wilson, S. Udry, B. Merín, V. Van Grootel, S. G. Sousa, N. Rando, D. Piazza, O. D. S. Demangeon, H. Rauer, D Ségransan, Gy. M. Szabó, B. Ulmer, Anders Erikson, M Steinberger, M. Güdel, Joshua N. Winn, I. Pagano, R. Ottensamer
article en
8 citations

Abstract

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 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 $\lambda _{\mathrm{c}}=67.8_{-49.0}^{+31.7}$ degrees (1$\sigma$). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b ($\lambda _{\mathrm{b}}=-2.96_{-10.30}^{+10.44}$), 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.

Monthly Notices of the Royal Astronomical SocietyVol. 536(3)
Eötvös Loránd University (HU), University of Geneva (CH), University of Bern (CH), Leiden University (NL), Queen's University Belfast (GB), Statistics Sweden (SE), Centre National de la Recherche Scientifique (FR), University of Vienna (AT), Planetary Science Institute (US), European Southern Observatory (DE), European Space Operations Centre (DE), Institute of Space Sciences (ES), Austrian Academy of Sciences (AT), University of Padua (IT), University of Liège (BE), Universidad de La Laguna (ES), University of California, Los Angeles (US), Stockholm University (SE), University of St Andrews (GB), Universidade do Porto (PT), Lund University (SE), National and Kapodistrian University of Athens (GR), Princeton University (US), Slovak Academy of Sciences (SK), Aix-Marseille Université (FR), University of Cambridge (GB), Université Paris Sciences et Lettres (FR), Institut d'Astrophysique de Paris (FR), European Space Agency (FR), Konkoly Observatory (HU), Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE), Department of Space (IN), ETH Zurich (CH), University of Warwick (GB), Sorbonne Université (FR), University of Oxford (GB), Graz University of Technology (AT), Institute of Astrophysics and Space Sciences (PT), Space Research Institute (AT), Institut d'Estudis Espacials de Catalunya (ES), European Space Astronomy Centre (ES), Osservatorio Astrofisico di Torino (IT), Cavendish Hospital (GB), Institute of Space Sciences (ES), Instituto de Física Teórica (ES), Institute of Astronomy (RU), Osservatorio Astrofisico di Catania (IT), FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ), HUN-REN Research Centre for Astronomy and Earth Sciences (HU), Centro de Astrobiología (ES), Instituto de Astrofísica de Canarias (ES), AlbaNova (SE), Astronomical Institute of the Slovak Academy of Sciences (SK), Computational Physics (United States) (US), Wolfgang Pauli Institute (AT), Astronomy and Space (AU), Osservatorio Astronomico di Padova (IT), Leiden Observatory, European Space Research and Technology Centre (NL), University College London (GB), Imperial College London (GB), Space Research Organisation Netherlands (NL), Institut de Mécanique Céleste et de Calcul des Éphémérides (FR), University of Turin (IT), Keele University (GB), Chalmers University of Technology (SE), Freie Universität Berlin (DE), University of Coimbra (PT), Ludwig-Maximilians-Universität München (DE), International Space Science Institute (CH), Robert Bosch (Germany) (DE)
National Science Foundation, Simons Foundation, Spine Education and Research Institute, Fondazione CRT, Slovenská Akadémia Vied, UK Space Agency, UK Research and Innovation, Ministerio de Ciencia, Innovación y Universidades, Centres de Recerca de Catalunya, European Space Agency, Royal Society, University of Warwick, European Commission, Deutsche Forschungsgemeinschaft, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Swedish National Space Agency, Austrian Science Fund, Fonds De La Recherche Scientifique - FNRS, Generalitat de Catalunya, Centre National d’Etudes Spatiales, Federación Española de Enfermedades Raras, Ministerio de Ciencia e Innovación, Agentúra na Podporu Výskumu a Vývoja, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, Instituto de Astrofísica de Canarias, Horizon 2020 Framework Programme, Science and Technology Facilities Council, Fundação para a Ciência e a Tecnologia, Staatssekretariat für Bildung, Forschung und Innovation, European Regional Development Fund, Agencia Estatal de Investigación, Nuclear Fuel Cycle and Supply Chain, H2020 European Research Council
Openalex Percentile: Top 10%
Stellar, planetary, and galactic studies
2.65
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