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

2023; EDP Sciences; Volume: 671; Linguagem: Inglês

10.1051/0004-6361/202244790

1432-0746

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. J. Hooton, M. Lendl, G. Olofsson, S. G. Sousa, V. Adibekyan, R. Alonso, G. Anglada‐Escudé, D. Barrado, S. C. C. Barros, W. Baumjohann, T. Beck, A. Bekkelien, Maria Bergomi, N. Billot, X. Bonfıls, A. Brandeker, C. Broeg, T. Bárczy, Zachory K. Berta-Thompson, J. Cabrera, C. Corral van Damme, Szilárd Csizmadia, M. B. Davies, M. Deleuil, O. D. S. Demangeon, Brice-Olivier Demory, J. Doty, A. Erikson, Michael Fausnaugh, H.-G. Florén, A. Fortier, L. Fossati, M. Fridlund, D. Futyan, D. Gandolfi, M. Gillon, P. Guterman, M. Güdel, Kevin Heng, K. G. Isaak, A. Jäckel, Jon M. Jenkins, L. L. Kiss, J. Laskar, David W. Latham, A. Lecavelier des Étangs, Alan M. Levine, C. Lovis, Demetrio Magrin, P. F. L. Maxted, E. Morgan, V. Nascimbeni, H. P. Osborn, R. Ottensamer, I. Pagano, Ε. Πάλλη, G. Peter, G. Piotto, D. Pollacco, Roberto Ragazzoni, N. Rando, H. Rauer, I. Ribas, G. Ricker, Sébastien Salmon, N. C. Santos, G. Scandariato, A. E. Simon, A. M. S. Smith, M Steinberger, M. Steller, Gyula M. Szabó, D. Ségransan, Avi Shporer, N. Thomas, M. Tschentscher, S. Udry, R. Vanderspek, V. Van Grootel, N. A. Walton,

Astrophysics and Star Formation Studies

The planetary system around the naked-eye star v 2 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 v 2 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 = 107.1361 −0.0022 +0.0019 days and T c = 2459009.7759 −0.0096 +0.0101 BJD TDB , 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 v 2 Lup d transits will warrant a comprehensive search for a moon around this outstanding exoplanet.