A full transit of v2 Lupi d and the search for an exomoon in its Hill sphere with CHEOPS
Guterman, P.; Alonso, R.; Deleuil, M.; Erikson, A.; Fridlund, M.; Queloz, D.; Rauer, H.; Olofsson, G.; Pallé, E.; Ribas, I.; Heng, K.; Güdel, M.; Isaak, K. G.; Scandariato, G.; Pagano, I.; Steller, M.; Thomas, N.; Baumjohann, W.; Gandolfi, D.; Fossati, L.; Smith, A. M. S.; Cabrera, J.; Ségransan, D.; Walton, N. A.; Ragazzoni, R.; Piotto, G.; Benz, W.; Deline, A.; Florén, H. -G.; Collier Cameron, A.; Adibekyan, V.; Alibert, Y.; Delrez, L.; Fortier, A.; Hoyer, S.; Bonfanti, A.; Salmon, S.; Sousa, S. G.; Wilson, T. G.; Bárczy, T.; Barrado, D.; Barros, S. C. C.; Beck, M.; Beck, T.; Billot, N.; Bonfils, X.; Brandeker, A.; Broeg, C.; Charnoz, S.; Davies, M. B.; Demory, B. -O.; Ehrenreich, D.; Gillon, M.; Jenkins, J. M.; Kiss, L. L.; Laskar, J.; Lecavelier des Etangs, A.; Lendl, M.; Lovis, C.; Magrin, D.; Maxted, P. F. L.; Nascimbeni, V.; Osborn, H. P.; Ottensamer, R.; Peter, G.; Pollacco, D.; Rando, N.; Ricker, G. R.; Santos, N. C.; Simon, A. E.; Udry, S.; Van Grootel, V.; Anglada, G.; Szabó, G. M.; Latham, D. W.; Vanderspek, R.; Bekkelien, A.; Fausnaugh, M. M.; Demangeon, O.; Futyan, D.; Steinberger, M.; Jäckel, A.; Bergomi, M.; Akinsanmi, B.; Morgan, E. H.; Csizmadia, S.; Levine, A. M.; Doty, J. P.; Shporer, A.; Berta-Thompson, Z. K.; Hooton, M.; Corral Van Damme, C.; Tschentscher, M.
Switzerland, Belgium, United Kingdom, Austria, France, Sweden, Portugal, Spain, Italy, Hungary, United States, Germany, Netherlands
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 = 107.1361−0.0022+0.0019 days and Tc = 2459009.7759−0.0096+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.
Undetrended and detrended light curves are only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/671/A154