Solar Photospheric Spectrum Microvariability I. Theoretical searches for proxies of radial-velocity jittering

Abstract

Extreme precision radial-velocity spectrometers enable extreme precision stellar spectroscopy. Searches for low-mass exoplanets around solar-type stars are limited by the physical variability in stellar spectra, such as the short-term jittering of apparent radial velocities. To understand the physical origins of such jittering, the solar spectrum is assembled, as far as possible, from basic principles. Surface convection is modeled with time-dependent 3D hydrodynamics, followed by the computation of hyper-high resolution spectra during numerous instances of the simulation sequences. The behavior of different classes of photospheric absorption lines is monitored to identify commonalities or differences between different classes of lines: weak or strong, neutral or ionized, high- or low-excitation, atomic or molecular. For Fe I and Fe II lines, the radial-velocity jittering over the small simulation area typically amounts to +-150 m/s, scaling to about 2 m/s for the full solar disk. Most photospheric lines vary in phase but with different amplitudes among different classes of lines. Radial-velocity excursions are greater for stronger and for ionized lines, decreasing at longer wavelengths. The differences between various line-groups are about one order of magnitude less than the full jittering amplitudes. By matching very precisely measured radial velocities to the characteristic jittering patterns between different line-groups should enable to identify and to remove a significant component of the stellar noise originating in granulation. To verify the modeling toward such a filter, predictions of solar center-to-limb dependences of jittering amplitudes are presented for different classes of lines, testable with spatially resolving solar telescopes connected to existing radial-velocity instruments.

arXiv comment18 pages, 20 figures, accepted for publication in Astronomy & Astrophysics

References in corpus (94)

• ESPRESSO@VLT -- On-sky performance and first results
• Simulations of stellar convection with CO5BOLD
• State of the Field: Extreme Precision Radial Velocities
• Using the Sun to estimate Earth-like planets detection capabilities II. Impact of plages
• 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
• Observational manifestations of solar magneto-convection -- center-to-limb variation
• Measuring precise radial velocities on individual spectral lines. I. Validation of the method and application to mitigate stellar activity
• The Sun as a planet-host star: Proxies from SDO images for HARPS radial-velocity variations
• SPIRou: nIR velocimetry & spectropolarimetry at the CFHT
• Small-scale solar magnetic fields
• EXPRES: A Next Generation RV Spectrograph in the Search for Earth-like Worlds
• Three years of Sun-as-a-star radial-velocity observations on the approach to solar minimum
• Observational constraints on the origin of the elements. I. 3D NLTE formation of Mn lines in late-type stars
• Atomic and Molecular Data for Optical Stellar Spectroscopy
• Three Years of HARPS-N High-Resolution Spectroscopy and Precise Radial Velocity Data for the Sun
• HARPS-N observes the Sun as a star
• Radial-Velocity Fitting Challenge. II. First results of the analysis of the data set
• Measuring precise radial velocities on individual spectral lines : II. Dependance of stellar activity signal on line depth
• The IAG solar flux atlas: Accurate wavelengths and absolute convective blueshift in standard solar spectra
• Bright points in the inter-network quiet Sun
• Separating planetary reflex Doppler shifts from stellar variability in the wavelength domain
• A comprehensive radial velocity error budget for next generation Doppler spectrometers
• Three-dimensional simulations of solar magneto-convection including effects of partial ionization
• Reconstructing the solar integrated radial velocity using MDI/SOHO
• Performance Verification of the EXtreme PREcision Spectrograph
• G-band Spectral Synthesis in Solar Magnetic Concentrations
• Granulation properties of giants, dwarfs, and white dwarfs from the CIFIST 3D model atmosphere grid
• Variability of stellar granulation and convective blueshift with spectral type and magnetic activity. I. K and G main sequence stars
• Radial Velocity Fitting Challenge. I. Simulating the data set including realistic stellar radial-velocity signals
• Three-dimensional simulations of near-surface convection in main-sequence stars. III. The structure of small-scale magnetic flux concentrations
• On the Feasibility of Intense Radial Velocity Surveys for Earth-twin Discoveries
• Towards Understanding Stellar Radial Velocity Jitter as a Function of Wavelength: The Sun as a Proxy
• The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
• The Stagger-grid: A grid of 3D stellar atmosphere models V. Synthetic stellar spectra and broad-band photometry
• A Granulation "Flicker"-based Measure of Stellar Surface Gravity
• Long-term radial-velocity variations of the Sun as a star: The HARPS view
• Hydrodynamical simulations of convection-related stellar micro-variability. I. Statistical relations for photometric and photocentric variability
• Stellar Granulation as the Source of High-Frequency Flicker in Kepler Light Curves
• Measuring precise radial velocities on individual spectral lines. III. Dependence of stellar activity signal on line formation temperature
• 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
• Statistical methods for exoplanet detection with radial velocities
• Unexpectedly strong effect of supergranulation on the detectability of Earth twins orbiting Sun-like stars with radial velocities
• Spectral variability of photospheric radiation due to faculae I: The Sun and Sun-like stars
• From Solar to Stellar Brightness Variations: The Effect of Metallicity
• Temporal evolution and correlations of optical activity indicators measured in Sun-as-a-star observations
• 3D Radiative MHD simulations of starspots
• Three-dimensional non-LTE radiative transfer effects in Fe I lines I. Flux sheet and flux tube geometries
• The correlation between photometric variability and radial velocity jitter, based on TESS and HARPS observations
• Understanding stellar activity-induced radial velocity jitter using simultaneous K2 photometry and HARPS RV measurements
• HARPS3 for a Roboticized Isaac Newton Telescope
• uvby-$\beta$ photometry of solar twins: the solar colors, model atmospheres, and the Teff and metallicity scales
• 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
• The SPIRou wavelength calibration for precise radial velocities in the near infrared
• A new method of correcting radial velocity time series for inhomogeneous convection
• A combined spectroscopic and photometric stellar activity study of Epsilon Eridani
• Spatially resolved spectroscopy across stellar surfaces. I. Using exoplanet transits to analyze 3-D stellar atmospheres
• Mitigating flicker noise in high-precision photometry. I -- Characterization of the noise structure, impact on the inferred transit parameters, and predictions for CHEOPS observations
• New wavelength calibration of the HARPS spectrograph
• Photometry as a proxy for stellar activity in radial velocity analyses
• Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, Hipparcos, Gaia, and SDSS systems
• Spectral variability of photospheric radiation due to faculae II: Facular contrasts for cool main-sequence stars
• 3-D non-LTE radiative transfer effects in Fe I lines: III. Line formation in magneto-hydrodynamic atmospheres
• The Stellar Variability Noise Floor for Transiting Exoplanet Photometry with PLATO
• Transit least-squares survey IV. Earth-like transiting planets expected from the PLATO mission
• The effects of granulation and supergranulation on Earth-mass planet detectability in the habitable zone around F6-K4 stars
• Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO
• The spectral impact of magnetic activity on disk-integrated HARPS-N solar observations: exploring new activity indicators
• Spatially resolved spectroscopy across stellar surfaces. II. High-resolution spectra across HD209458 (G0V)
• Stellar granulation as seen in disk-integrated intensity. I. Simplified theoretical modeling
• Predicting Granulation "Flicker" and Radial Velocity "Jitter" from Spectroscopic Observables
• Probing photospheric magnetic fields with new spectral line pairs
• Non-magnetic photospheric bright points in 3D simulations of the solar atmosphere
• A limit on variations in the fine-structure constant from spectra of nearby Sun-like stars
• Investigation of intergranular bright points from the New Vacuum Solar Telescope
• Spatially resolved spectroscopy across stellar surfaces. V. Observational prospects: Toward Earth-like exoplanet detection
• Spatially resolved spectroscopy across stellar surfaces. III. Photospheric Fe I lines across HD189733A (K1 V)
• Testing the Spectroscopic Extraction of Suppression of Convective Blueshift
• Spatially resolved spectroscopy across stellar surfaces. IV. F, G, & K-stars: Synthetic 3D spectra at hyper-high resolution
• Unsigned magnetic flux proxy from solar optical intensity spectra
• Inference of stellar parameters from brightness variations
• Connecting measurements of solar and stellar brightness variations
• The dark side of solar photospheric G-band bright points
• Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. II. The role of convection accross the H-R diagram
• Spectral Line Depth Variability in Radial Velocity Spectra
• The Zeeman effect in the G band
• Probing Galactic variations in the fine-structure constant using solar twin stars: systematic errors
• Reducing activity-induced variations in a radial-velocity time series of the Sun as a star
• A Harsh Test of Far-Field Scrambling with the Habitable Zone Planet Finder and the Hobby Eberly Telescope
• A Refined Model of Convectively-Driven Flicker in Kepler Light Curves
• The signature of granulation in a solar power spectrum as seen with CO${}^5$BOLD
• Probing Galactic variations in the fine-structure constant using solar twin stars: methodology and results
• The Average Physical Properties of A-G Stars Derived from uvby-H$\beta$ Strömgren-Crawford Photometry as the Basis for a Spectral-Classification Synthetical Approach

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• GRASS II: Simulations of Potential Granulation Noise Mitigation Methods
• Solar photospheric spectrum microvariability II. Observed relations to magnetic activity and radial-velocity modulation
• The CARMENES search for exoplanets around M dwarfs. The impact of rotation and magnetic fields on the radial velocity jitter in cool stars
• Towards understanding stellar variability at the sub m/s level: granulation-induced variability across the optical spectrum
• Solar photospheric spectrum microvariability III. Radial velocities and line profiles in magnetic active-region granulation