Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO

Author(s): S. Sulis, M. Lendl, H. M. Cegla, L. F. Rodríguez Díaz, L. Bigot, V. Van Grootel, A. Bekkelien, A. Collier Cameron, P. F.L. Maxted, A. E. Simon, C. Lovis, G. Scandariato, G. Bruno, D. Nardiello, A. Bonfanti, M. Fridlund, C. M. Persson, S. Salmon, S. G. Sousa, T. G. Wilson, A. Krenn, S. Hoyer, A. Santerne, D. Ehrenreich, Y. Alibert, R. Alonso, G. Anglada, T. Bárczy, D. Barrado Y Navascues, S. C.C. Barros, W. Baumjohann, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, A. Brandeker, C. Broeg, J. Cabrera, S. Charnoz, C. Corral Van Damme, Sz Csizmadia, M. B. Davies, M. Deleuil, A. Deline, L. Delrez, O. D.S. Demangeon, B. O. Demory, A. Erikson, A. Fortier, L. Fossati, D. Gandolfi, M. Gillon, M. Güdel, K. Heng, K. G. Isaak, L. L. Kiss, J. Laskar, A. Lecavelier Des Etangs, D. Magrin, M. Munari, V. Nascimbeni, G. Olofsson, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, I. Ribas, M. Rieder, N. C. Santos, D. Ségransan, A. M.S. Smith, M. Steinberger, M. Steller, Gy M. Szabó, N. Thomas, S. Udry, N. A. Walton, D. Wolter
Abstract: Context. Stellar granulation generates fluctuations in photometric and spectroscopic data whose properties depend on the stellar type, composition, and evolutionary state. Characterizing granulation is key for understanding stellar atmospheres and detecting planets. Aims. We aim to detect the signatures of stellar granulation, link spectroscopic and photometric signatures of convection for main-sequence stars, and test predictions from 3D hydrodynamic models. Methods. For the first time, we observed two bright stars (Teff = 5833 and 6205 K) with high-precision observations taken simultaneously with CHEOPS and ESPRESSO. We analyzed the properties of the stellar granulation signal in each individual dataset. We compared them to Kepler observations and 3D hydrodynamic models. While isolating the granulation-induced changes by attenuating and filtering the p-mode oscillation signals, we studied the relationship between photometric and spectroscopic observables. Results. The signature of stellar granulation is detected and precisely characterized for the hotter F star in the CHEOPS and ESPRESSO observations. For the cooler G star, we obtain a clear detection in the CHEOPS dataset only. The TESS observations are blind to this stellar signal. Based on CHEOPS observations, we show that the inferred properties of stellar granulation are in agreement with both Kepler observations and hydrodynamic models. Comparing their periodograms, we observe a strong link between spectroscopic and photometric observables. Correlations of this stellar signal in the time domain (flux versus radial velocities, RV) and with specific spectroscopic observables (shape of the cross-correlation functions) are however difficult to isolate due to S/N dependent variations. Conclusions. In the context of the upcoming PLATO mission and the extreme precision RV surveys, a thorough understanding of the properties of the stellar granulation signal is needed. The CHEOPS and ESPRESSO observations pave the way for detailed analyses of this stellar process.
Organisation(s): Department of Astrophysics
External organisation(s): Aix-Marseille Université, Université de Genève, University of Warwick, Aarhus University, Observatoire de la Cote da Azur, Université Côte d'Azur, Université de Liège, University of St. Andrews, Keele University, Universität Bern, INAF-Osservatorio Astrofisico di Catania, Osservatorio Astronomico, Österreichische Akademie der Wissenschaften (ÖAW), Leiden University, Chalmers University of Technology, Universidade do Porto, Institute of Astrophysics of the Canary Islands, University of La Laguna, Spanish National Research Council (CSIC), Institute of Space Studies of Catalonia (IEEC), Admatis Ltd., European Space Astronomy Centre (ESA), University of Grenoble Alpes, Stockholm University, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Université de Paris, Science and Operations Department - Science Division (SCI-SC), Lund University, Università degli Studi di Torino, Eötvös Loránd Research Network, Eötvös Loránd University Budapest, Université de recherche Paris Sciences et Lettres, Université Paris VI - Pierre-et-Marie-Curie, University of Padova, Eidgenössische Technische Hochschule Zürich, University of Cambridge, Technische Universität Berlin, Freie Universität Berlin (FU), Universitat Autònoma de Barcelona
Journal: Astronomy and Astrophysics
Volume: 670
No. of pages: 30
ISSN: 0004-6361
DOI: https://doi.org/10.1051/0004-6361/202244223
Publication date: 02-2023
Peer reviewed: Yes
Austrian Fields of Science 2012: 103003 Astronomy, 103038 Space exploration, 103004 Astrophysics
Keywords
ASJC Scopus subject areas: Astronomy and Astrophysics, Space and Planetary Science
Portal url: https://ucrisportal.univie.ac.at/en/publications/a8d4791e-bbce-44a7-baba-1e6ef2d50e38

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