Hydrodynamical simulations of convection-related stellar micro-variability. II. The enigmatic granul

@article{Ludwig2009HydrodynamicalSO,
  title={Hydrodynamical simulations of convection-related stellar micro-variability. II. The enigmatic granul},
  author={H. Ludwig and R. Samadi and M. Steffen and T. Appourchaux and F. Baudin and K. Belkacem and P. Boumier and M. Goupil and E. Michel},
  journal={Astronomy and Astrophysics},
  year={2009}
}
Context. Local-box hydrodynamical model atmospheres provide statistical information about a star’s emergent radiation field which allows one to predict the level of its granulation-related micro-variability. Space-based photometry is now sufficiently accurate to test model predictions. Aims. We aim to model the photometric granulation background of HD 49933 as well as the Sun, and compare the predictions to the measurements obtained by the CoRoT and SOHO satellite missions. Methods. We… Expand

Figures and Tables from this paper

Hydrodynamical model atmospheres: Their impact on stellar spectroscopy and asteroseismology of late-type stars
Hydrodynamical, i.e. multi-dimensional and time-dependent, model atmospheres of late-type stars have reached a high level of realism. They are commonly applied in high-fidelity work on stellarExpand
Stellar granulation as seen in disk-integrated intensity I. Simplified theoretical modeling
Context. Solar granulation has been known for a long time to be a surface manifestation of convection. The space-borne missions CoRoT and Kepler enable us to observe the signature of this phenomenaExpand
Stellar Granulation as the Source of High-frequency Flicker in Kepler Light Curves
A large fraction of cool, low-mass stars exhibit brightness fluctuations that arise from a combination of convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. MuchExpand
Stellar granulation as seen in disk-integrated intensity. II. Theoretical scaling relations compared with observations
Context. A large set of stars observed by CoRoT and Kepler shows clear evidence for the presence of a stellar background, which is interpreted to arise from surface convection, i.e., granulation.Expand
Improved calibration of the radii of cool stars based on 3D simulations of convection: implications for the solar model
Main sequence, solar-like stars (M < 1.5 Msun) have outer convective envelopes that are sufficiently thick to affect significantly their overall structure. The radii of these stars, in particular,Expand
Granulation in red giants: observations by the Kepler mission and three-dimensional convection simulations
The granulation pattern that we observe on the surface of the Sun is due to hot plasma rising to the photosphere where it cools down and descends back into the interior at the edges of granules. ThisExpand
The connection between stellar granulation and oscillation as seen by the Kepler mission
Context. The long and almost continuous observations by Kepler show clear evidence of a granulation background signal in a large sample of stars, which is interpreted as the surface manifestation ofExpand
The Stagger-grid: A grid of 3D stellar atmosphere models - I. Methods and general properties
Aims. We present the Stagger-grid, a comprehensive grid of time-dependent, three-dimensional (3D), hydrodynamic model atmospheres for late-type stars with realistic treatment of rad iative transfer,Expand
VARIATION OF STELLAR ENVELOPE CONVECTION AND OVERSHOOT WITH METALLICITY
We examine how metallicity affects convection and overshoot in the superadiabatic layer of main sequence stars. We present results from a grid of three-dimensional radiation hydrodynamic simulationsExpand
Granulation properties of giants, dwarfs, and white dwarfs from the CIFIST 3D model atmosphere grid
3D model atmospheres for giants, dwarfs, and white dwarfs, computed with the CO5BOLD code and part of the CIFIST grid, have been used for spectroscopic and asteroseismic studies. Unlike existingExpand
...
1
2
3
...

References

SHOWING 1-10 OF 42 REFERENCES
Hydrodynamical simulations of convection-related stellar micro-variability
We used a series of CO5BOLD hydrodynamical model atmospheres covering stellar objects from white dwarfs to red giants to derive theoretical estimates of the photometric and photocentric stellarExpand
A solar surface dynamo
Context. Observations indicate that the “quiet” solar photosphere outside active regions contains considerable amounts of magnetic energy and magnetic flux, with mixed polarity on small scales. TheExpand
A grid of MARCS model atmospheres for late-type stars. I. Methods and general properties
Context. In analyses of stellar spectra and colours, and for the analysis of integrated light from galaxies, a homogeneous grid of model atmospheres of late-type stars and corresponding flux spectraExpand
Accurate fundamental parameters of CoRoT asteroseismic targets - The solar-like stars HD 49933, HD 175726, HD 181420, and HD 181906
Context. The CoRoT satellite has provided high-quality light curves of several solar-like stars. Analysis of these light curves provides oscillation frequencies that make it possible to probe theExpand
A spectroscopic study of southern (candidate) gamma Doradus stars. II. Detailed abundance analysis and fundamental parameters
Context. The γ Doradus stars are a recent class of variable main sequence F-type stars located on the red edge of the Cepheid instability strip. They pulsate in gravity modes, and this makes themExpand
FIRST RESULTS FROM VIRGO, THE EXPERIMENT FOR HELIOSEISMOLOGY AND SOLAR IRRADIANCE MONITORING ON SOHO
First results from the VIRGO experiment (Variability of solar IRradiance and Gravity Oscillations) on the ESA/NASA Mission SOHO (Solar and Heliospheric Observatory) are reported. The observationsExpand
High precision determination of the atmospheric parameters and abundances of the COROT main targets
Context. One of the main goals of the COROT mission is to get precise photometric observations of selected bright stars in order to allow the modelling of their interior through asteroseismology.Expand
A substantial amount of hidden magnetic energy in the quiet Sun
TLDR
Three-dimensional radiative transfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales finds a ubiquitous tangled magnetic field with an average strength of ∼130 G. Expand
The Nature of p-Modes and Granulation in Procyon: New MOST* Photometry and New Yale Convection Models
We present new photometry of Procyon, obtained by MOST during a 38 day run in 2007, and frequency analyses of those data. The long time coverage and low point-to-point scatter of the light curveExpand
Solar-like oscillations in HD 181420: data analysis of 156 days of CoRoT data
Context. The estimate of solar-like oscillation properties, such as their frequencies, amplitudes and lifetimes, is challenging because of their low amplitudes and will benefit from long andExpand
...
1
2
3
4
5
...