Hint of an exocomet transit in the CHEOPS light curve of HD 172555

Autor(en)

F. Kiefer, V. Van Grootel, A. Lecavelier Des Etangs, Gy M. Szabó, A. Brandeker, C. Broeg, A. Collier Cameron, A. Deline, G. Olofsson, T. G. Wilson, S. G. Sousa, D. Gandolfi, G. Hébrard, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, J. Cabrera, S. Charnoz, Sz Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. D.S. Demangeon, B. O. Demory, D. Ehrenreich, A. Erikson, A. Fortier, L. Fossati, M. Fridlund, M. Gillon, M. Güdel, K. Heng, S. Hoyer, K. G. Isaak, L. L. Kiss, J. Laskar, M. Lendl, C. Lovis, D. Magrin, P. F.L. Maxted, M. Munari, V. Nascimbeni, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, D. Piazza, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, C. Reimers, I. Ribas, N. C. Santos, G. Scandariato, D. Ségransan, A. E. Simon, A. M.S. Smith, M. Steller, N. Thomas, S. Udry, I. Walter, N. A. Walton

Abstrakt

HD 172555 is a young (∼20 Myr) A7V star surrounded by a 10 au wide debris disk suspected to be replenished partly by collisions between large planetesimals. Small evaporating transiting bodies, that is exocomets, have also been detected in this system by spectroscopy. After β Pictoris, this is another example of a system possibly witnessing a phase of the heavy bombardment of planetesimals. In such a system, small bodies trace dynamical evolution processes. We aim to constrain their dust content by using transit photometry. We performed a 2-day-long photometric monitoring of HD 172555 with the CHEOPS space telescope in order to detect shallow transits of exocomets with a typical expected duration of a few hours. The large oscillations in the light curve indicate that HD 172555 is a δ Scuti pulsating star. After removing those dominating oscillations, we found a hint of a transient absorption. If fitted with an exocomet transit model, it would correspond to an evaporating body passing near the star at a distance of 6.8±1.4R∗ (or 0.05±0.01 au) with a radius of 2.5 km. These properties are comparable to those of the exocomets already found in this system using spectroscopy, as well as those found in the β Pic system. The nuclei of the Solar System's Jupiter family comets, with radii of 2-6 km, are also comparable in size. This is the first piece of evidence of an exocomet photometric transit detection in the young system of HD 172555.

Organisation(en)

Institut für Astrophysik, Campus Information & Business Intelligence Services

Externe Organisation(en)

Université Paris VI - Pierre-et-Marie-Curie, Université de recherche Paris Sciences et Lettres, Université de Liège, Eötvös Loránd University Budapest, Stockholm University, Universität Bern, University of St. Andrews, Universität Genf, Universidade do Porto, Università degli Studi di Torino, Observatoire de Haute-Provence, Instituto de Astrofísica de Canarias (IAC), Universidad de La Laguna, Universitat Autònoma de Barcelona , Spanish National Research Council (CSIC), Institut d'Estudis Espacials de Catalunya (IEEC), Admatis, European Space Astronomy Centre (ESA), Österreichische Akademie der Wissenschaften (ÖAW), Université Grenoble-Alpes, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, Lund University, Aix-Marseille Université, Leiden University, Chalmers University of Technology, University of Warwick, European Space Research & Technology Centre (ESA/ESTEC), MTA Társadalomtudományi Kutatóközpont, INAF - Osservatorio Astronomico di Padova, Keele University, INAF-Osservatorio Astrofisico di Catania, Università degli Studi di Padova, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU)

Journal

Astronomy and Astrophysics

Band

671

Anzahl der Seiten

12

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/202245104

Publikationsdatum

03-2023

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik, 103038 Weltraumforschung

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/f7ff9cae-f33f-4f56-ad01-0400a0162b0f