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

Ehrenreich, D.; Delrez, L.; Akinsanmi, B.; Wilson, T. G.; Bonfanti, A.; Beck, M.; Benz, W.; Hoyer, S.; Queloz, D.; Alibert, Y.; Charnoz, S.; Collier Cameron, A.; Deline, A.; Hooton, M.; Lendl, M.; Olofsson, G.; Sousa, S. G.; Adibekyan, V.; Alonso, R.; Anglada, G.; Barrado, D.; Barros, S. C. C.; Baumjohann, W.; Beck, T.; Bekkelien, A.; Bergomi, M.; Billot, N.; Bonfils, X.; Brandeker, A.; Broeg, C.; Barczy, T.; Berta-Thompson, Z. K.; Cabrera, J.; Corral Van Damme, C.; Csizmadia, S.; Davies, M. B.; Deleuil, M.; Demangeon, O.; Demory, B. -o.; Doty, J. P.; Erikson, A.; Fausnaugh, M. M.; Floren, H. -G.; Fortier, A.; Fossati, L.; Fridlund, M.; Futyan, D.; Gandolfi, D.; Gillon, M.; Guterman, P.; Guedel, M.; Heng, K.; Isaak, K. G.; Jackel, A.; Jenkins, J. M.; Kiss, L. L.; Laskar, J.; Latham, D. W.; Lecavelier des Etangs, A.; Levine, A. M.; Lovis, C.; Magrin, D.; Maxted, P. F. L.; Morgan, E. H.; Nascimbeni, V.; Osborn, H. P.; Ottensamer, R.; Pagano, I.; Palle, E.; Peter, G.; Piotto, G.; Pollacco...

Abstract

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-circle plus). 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-circle plus 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 similar to 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.

Citation

Ehrenreich, D., Delrez, L., Akinsanmi, B., Wilson, T. G., Bonfanti, A., Beck, M., …Walton, N. A. (2023). A full transit of nu(2) Lupi d and the search for an exomoon in its Hill sphere with CHEOPS. Astronomy & Astrophysics, 671, Article A154. https://doi.org/10.1051/0004-6361/202244790

• Journal Article Type: Article
• Acceptance Date: Dec 3, 2022
• Online Publication Date: Mar 20, 2023
• Publication Date: Mar 20, 2023
• Deposit Date: Aug 15, 2023
• Journal: ASTRONOMY & ASTROPHYSICS
• Print ISSN: 0004-6361
• Electronic ISSN: 1432-0746
• Publisher: EDP Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 671
• Article Number: A154
• DOI: https://doi.org/10.1051/0004-6361/202244790
• Publisher URL: https://www.aanda.org/articles/aa/full_html/2023/03/aa44790-22/aa44790-22.html