Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO
Abstract
Stellar granulation generates fluctuations in photometric and spectroscopic data whose properties depend on the stellar type, composition, and evolutionary state. In this study, 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. For the first time, we observed two bright stars (Teff = 5833 K 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 data set. We compared them to Kepler observations and 3D hydrodynamic models. While isolating the granulation-induced changes by attenuating the p-mode oscillation signals, we studied the relationship between photometric and spectroscopic observables. 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 vs RV) and with specific spectroscopic observables (shape of the cross-correlation functions) are however difficult to isolate due to signal-to-noise dependent variations. 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.
Keywords
Cite
@article{arxiv.2211.14398,
title = {Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO},
author = {S. Sulis and M. Lendl and H. Cegla and L. F. Rodriguez Diaz and L. Bigot and V. Van Grootel and A. Bekkelien and A. Collier Cameron and P. F. L. Maxted and A. E. Simon and C. Lovis and G. Scandariato and G. Bruno and D. Nardiello and A. Bonfanti and M. Fridlund and C. M. Persson and S. Salmon and S. G. Sousa and T. G. Wilson and A. Krenn and S. Hoyer and A. Santerne and D. Ehrenreich and Y. Alibert and R. Alonso and G. Anglada and T. Bárczy and D. Barrado y Navascues and S. C. C. Barros and W. Baumjohann and M. Beck and T. Beck and W. Benz and N. Billot and X. Bonfils and L. Borsato and A. Brandeker and C. Broeg and J. Cabrera and S. Charnoz and C. Corral van Damme and Sz. Csizmadia and M. B. Davies and M. Deleuil and A. Deline and L. Delrez and O. D. S. Demangeon and B. -O. Demory and A. Erikson and A. Fortier and L. Fossati and D. Gandolfi and M. Gillon and M. Güdel and K. Heng and K. G. Isaak and L. L. Kiss and J. Laskar and A. Lecavelier des Etangs and D. Magrin and M. Munari and V. Nascimbeni and G. Olofsson and R. Ottensamer and I. Pagano and E. Pallé and G. Peter and G. Piotto and D. Pollacco and D. Queloz and R. Ragazzoni and N. Rando and H. Rauer and I. Ribas and M. Rieder and N. C. Santos and D. Ségransan and A. M. S. Smith and M. Steinberger and M. Steller and Gy. M. Szabó and N. Thomas and S. Udry and N. A. Walton and D. Wolter},
journal= {arXiv preprint arXiv:2211.14398},
year = {2023}
}
Comments
Accepted to A&A, 30 pages, 21 figures, 10 tables (one online)