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.

arXiv commentAccepted to A&A, 30 pages, 21 figures, 10 tables (one online)

References in corpus (73)

• emcee: The MCMC Hammer
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Transiting Exoplanet Survey Satellite
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• A new generation of PARSEC-COLIBRI stellar isochrones including the TP-AGB phase
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• ESPRESSO@VLT -- On-sky performance and first results
• Spectroscopy Made Easy: Evolution
• Testing Scaling Relations for Solar-Like Oscillations from the Main Sequence to Red Giants using Kepler Data
• Radial Velocity Jitter in Stars from the California and Carnegie Planet Search at Keck Observatory
• Improved spectroscopic parameters for transiting planet hosts
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs I. New atmospheric parameters and masses for 48 stars with planets
• A simple method to estimate radial velocity variations due to stellar activity using photometry
• The CHEOPS mission
• Planetary detection limits taking into account stellar noise. I. Observational strategies to reduce stellar oscillation and granulation effects
• The connection between stellar granulation and oscillation as seen by the Kepler mission
• CLES, Code Liegeois d'Evolution Stellaire
• ARES v2 - new features and improved performance
• Granulation in Red Giants: observations by the Kepler mission and 3D convection simulations
• Solar Oscillations and Convection: II. Excitation of Radial Oscillations
• Asteroseismology of solar-type stars
• A Grid of 3D Stellar Atmosphere Models of Solar Metallicity: I. General Properties, Granulation and Atmospheric Expansion
• On the Mass of CoRoT-7b
• Photometric Variability in Kepler Target Stars: The Sun Among Stars -- A First Look
• Three years of Sun-as-a-star radial-velocity observations on the approach to solar minimum
• An observational correlation between stellar brightness variations and surface gravity
• Expected performances of the Characterising Exoplanet Satellite (CHEOPS) III. Data reduction pipeline: architecture and simulated performances
• Age consistency between exoplanet hosts and field stars
• Characterising stellar micro-variability for planetary transit searches
• Revising the ages of planet-hosting stars
• Three Years of HARPS-N High-Resolution Spectroscopy and Precise Radial Velocity Data for the Sun
• The quest for the solar g modes
• SWEET-Cat 2.0: The Cat just got SWEETer; Higher quality spectra and precise parallaxes from GAIA eDR3
• Stellar Activity in the Broad-Band Ultraviolet
• Filtering solar-like oscillations for exoplanet detection in radial velocity observations
• SPECIES I: Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars
• CHEOPS observations of the HD 108236 planetary system: A fifth planet, improved ephemerides, and planetary radii
• Theoretical seismology in 3D : nonlinear simulations of internal gravity waves in solar-like stars
• Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops
• Interaction Between Convection and Pulsation
• A PSF-based Approach to TESS High quality data Of Stellar clusters (PATHOS) -- I. Search for exoplanets and variable stars in the field of 47 Tuc
• Three-dimensional simulations of near-surface convection in main-sequence stars - II. Properties of granulation and spectral lines
• Granulation properties of giants, dwarfs, and white dwarfs from the CIFIST 3D model atmosphere grid
• Photospheric and chromospheric magnetic activity of seismic solar analogs. Observational inputs on the solar/stellar connection from Kepler and Hermes
• The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - II. Horizontal and Temporal Averaging and Spectral Line Formation
• WASP-186 and WASP-187: two hot Jupiters discovered by SuperWASP and SOPHIE with additional observations by TESS
• A PSF-based Approach to TESS High quality data Of Stellar clusters (PATHOS) -- II. Search for exoplanets in open clusters of the southern ecliptic hemisphere and their frequency
• Reinvestigating $\alpha$ Cen AB in light of asteroseismic forward and inverse methods
• A Granulation "Flicker"-based Measure of Stellar Surface Gravity
• Radial Velocity Variations of Photometrically Quiet, Chromospherically Inactive Kepler Stars: A Link Between RV Jitter and Photometric Flicker
• Hydrodynamical simulations of convection-related stellar micro-variability. I. Statistical relations for photometric and photocentric variability
• Estimating Stellar Radial Velocity Variability from Kepler and GALEX: Implications for the Radial Velocity Confirmation of Exoplanets
• Stellar Surface Magneto-Convection as a Source of Astrophysical Noise III. Sun-as-a-star Simulations and Optimal Noise Diagnostics
• Stellar granulation as seen in disk-integrated intensity. II. Theoretical scaling relations compared with observations
• Understanding stellar activity-induced radial velocity jitter using simultaneous K2 photometry and HARPS RV measurements
• FliPer: A global measure of power density to estimate surface gravities of main-sequence Solar-like stars and red giants
• Three-dimensional simulations of near-surface convection in main-sequence stars. IV. Effect of small-scale magnetic flux concentrations on centre-to-limb variation and spectral lines
• Mitigating flicker noise in high-precision photometry. I -- Characterization of the noise structure, impact on the inferred transit parameters, and predictions for CHEOPS observations
• A PSF-based Approach to TESS High quality data Of Stellar clusters (PATHOS) -- IV. Candidate exoplanets around stars in open clusters: frequency and age-planetary radius distribution
• The effects of granulation and supergranulation on Earth-mass planet detectability in the habitable zone around F6-K4 stars
• Surface gravities for 15,000 Kepler stars measured from stellar granulation and validated with Gaia DR2 parallaxes
• Modelling solar irradiance variability on time scales from minutes to months
• 3D magneto-hydrodynamical simulations of stellar convective noise for improved exoplanet detection. I. Case of regularly sampled radial velocity observations
• Predicting Granulation "Flicker" and Radial Velocity "Jitter" from Spectroscopic Observables
• Searching for g modes: Part I. A new calibration of the GOLF instrument
• Expected performances of the Characterising Exoplanet Satellite (CHEOPS) II. The CHEOPS simulator
• Spatially resolved spectroscopy across stellar surfaces. V. Observational prospects: Toward Earth-like exoplanet detection
• Changes in granulation scales over the solar cycle seen with SDO/HMI and Hinode/SOT
• Velocity-intensity asymmetry reversal of solar radial p-modes

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