A full transit of v ²Lupi d and the search for an exomoon in its Hill sphere with CHEOPS

Author(s)

D. Ehrenreich, L. Delrez, B. Akinsanmi, T. G. Wilson, A. Bonfanti, M. Beck, W. Benz, S. Hoyer, D. Queloz, Y. Alibert, S. Charnoz, A. Collier Cameron, A. Deline, M. Hooton, M. Lendl, G. Olofsson, S. G. Sousa, V. Adibekyan, R. Alonso, G. Anglada, D. Barrado, S. C.C. Barros, W. Baumjohann, T. Beck, A. Bekkelien, M. Bergomi, N. Billot, X. Bonfils, A. Brandeker, C. Broeg, T. Bárczy, Z. K. Berta-Thompson, J. Cabrera, C. Corral Van Damme, S. Csizmadia, M. B. Davies, M. Deleuil, O. Demangeon, B. O. Demory, J. P. Doty, A. Erikson, M. M. Fausnaugh, H. G. Florén, A. Fortier, L. Fossati, M. Fridlund, D. Futyan, D. Gandolfi, M. Gillon, P. Guterman, M. Güdel, K. Heng, K. G. Isaak, A. Jäckel, J. M. Jenkins, L. L. Kiss, J. Laskar, D. W. Latham, A. Lecavelier Des Etangs, A. M. Levine, C. Lovis, D. Magrin, P. F.L. Maxted, E. H. Morgan, V. Nascimbeni, H. P. Osborn, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. R. Ricker, S. Salmon, N. C. Santos, G. Scandariato, A. E. Simon, A. M.S. Smith, M. Steinberger, M. Steller, G. M. Szabó, D. Ségransan, A. Shporer, N. Thomas, M. Tschentscher, S. Udry, R. Vanderspek, V. Van Grootel, N. A. Walton

Abstract

The planetary system around the naked-eye star v2 Lupi (HD 136352; TOI-2011) is composed of three exoplanets with masses of 4.7, 11.2, and 8.6 Earth masses (M⊕). The TESS and CHEOPS missions revealed that all three planets are transiting and have radii straddling the radius gap separating volatile-rich and volatile-poor super-earths. Only a partial transit of planet d had been covered so we re-observed an inferior conjunction of the long-period 8.6 M⊕ exoplanet v2 Lup d with the CHEOPS space telescope. We confirmed its transiting nature by covering its whole 9.1 h transit for the first time. We refined the planet transit ephemeris to P = 107.13610.0022+0.0019 days and Tc = 2459009.77590.0096+0.0101 BJDTDB, improving by ~40 times on the previously reported transit timing uncertainty. This refined ephemeris will enable further follow-up of this outstanding long-period transiting planet to search for atmospheric signatures or explore the planet s Hill sphere in search for an exomoon. In fact, the CHEOPS observations also cover the transit of a large fraction of the planet s Hill sphere, which is as large as the Earth s, opening the tantalising possibility of catching transiting exomoons. We conducted a search for exomoon signals in this single-epoch light curve but found no conclusive photometric signature of additional transiting bodies larger than Mars. Yet, only a sustained follow-up of v2 Lup d transits will warrant a comprehensive search for a moon around this outstanding exoplanet.

Organisation(s)

Department of Astrophysics

External organisation(s)

Université de Genève, Université de Liège, University of St. Andrews, Österreichische Akademie der Wissenschaften (ÖAW), Universität Bern, Aix-Marseille Université, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Université de Paris, Stockholm University, Universidade do Porto, Institute of Astrophysics of the Canary Islands, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), European Space Astronomy Centre (ESA), Osservatorio Astronomico, University of Grenoble Alpes, Admatis Ltd., University of Colorado, Boulder, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Science and Operations Department - Science Division (SCI-SC), Lund University, Noqsi Aerospace Ltd., Massachusetts Institute of Technology, Leiden University, Chalmers University of Technology, Università degli Studi di Torino, National Institute for Earth Sciences & Astronomy (INSU-CNRS), University of Warwick, National Aeronautics & Space Administration (NASA), Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Harvard-Smithsonian Center for Astrophysics, Université Paris VI - Pierre-et-Marie-Curie, Keele University, INAF-Osservatorio Astrofisico di Catania, University of Padova, Technische Universität Berlin, Freie Universität Berlin (FU)

Journal

Astronomy and Astrophysics

Volume

671

No. of pages

16

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/202244790

Publication date

03-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics, 103038 Space exploration

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/ed514dc8-2154-4c91-b01a-d5aa601f7594