Surface layer independent model fitting by phase matching: theory and application to HD49933 an HD177153 (aka Perky)

Abstract

Aims. To describe the theory of surface layer independent model fitting by phase matching and to apply this to the stars HD49933 observed by CoRoT, and HD177153 (aka Perky), observed by Kepler Methods. We use theoretical analysis, phase shifts, and model fitting. Results. We define the inner and outer phase shifts of a frequency set of a model star and show that the outer phase shifts are (almost) independent of degree $\ell$, and that a function of the inner phase shifts (the phase function) collapses to an $\ell$ independent function of frequency in the outer layers. We then show how to use this result in a model fitting technique to find a best fit model to an observed frequency set by calculating the inner phase shifts of a model using the observed frequencies and determining the extent to which the phase function collapses to a single function of frequency in the outer layers. We give two examples applying this technique to the frequency sets of HD49933 observed by CoRoT and HD177153 (aka Perky) observed by Kepler, and compare our results with those of previous studies and show that they are compatible with those obtained using different techniques. We show that there can be many different models that fit the data within the errors and that better precision on the frequencies is needed to discriminate between the models. We compare this technique to that using the ratios of small to large separations, showing that in principle it is more accurate and avoids the problem of correlated errors in separation ratio fitting.

9 pages 15 figures

References in corpus (17)

• Validation of the new Hipparcos reduction
• Low Temperature Opacities
• Correcting stellar oscillation frequencies for near-surface effects
• Fundamental Properties of Stars using Asteroseismology from Kepler & CoRoT and Interferometry from the CHARA Array
• Stellar Diameters and Temperatures III. Main Sequence A, F, G, & K Stars: Additional high-precision measurements and empirical relations
• Accurate parameters of 93 solar-type Kepler targets
• Stellar ages and convective cores in field main-sequence stars: first asteroseismic application to two Kepler targets
• Modeling the Formation of Globular Cluster Systems in the Virgo Cluster
• A Stellar Model-fitting Pipeline for Asteroseismic Data from the Kepler Mission
• A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry
• Accurate fundamental parameters of CoRoT asteroseismic targets: the solar-like stars HD 49933, HD 175726, HD 181420 and HD 181906
• The diameter of the CoRoT target HD 49933. Combining the 3D limb darkening, asteroseismology, and interferometry
• The nature of p-modes and granulation in HD 49933 observed by CoRoT
• On the use of the ratio of small to large separations in asteroseismic model fitting
• Impact of the physical processes in the modeling of HD49933
• Probing the parameter space of HD 49933: a comparison between global and local methods
• On the use of the average large separation in surface layer independent model fitting

Cited by in corpus (14)

• Gaia FGK Benchmark Stars: Effective temperatures and surface gravities
• Global Seismology of the Sun
• Surface-effect corrections for oscillation frequencies of evolved stars
• Using seismic inversions to obtain an internal mixing processes indicator for main-sequence solar-like stars
• Convective boundary mixing in low- and intermediate-mass stars I. Core properties from pressure-mode asteroseismology
• The robustness of asteroseismic estimates of global stellar parameters to surface term corrections
• Mixed Modes and Asteroseismic Surface Effects: I. Analytic Treatment
• Differential Modelling Systematics across the HR Diagram from Asteroseismic Surface Corrections
• Thorough characterisation of the 16 Cygni system. Part II. Seismic inversions of the internal structure
• Robust asteroseismic properties of the bright planet host HD 38529
• Impact of magnetic activity on inferred stellar properties of main sequence Sun-like stars
• Asteroseismic modelling strategies in the PLATO era I. Mean density inversions and direct treatment of the seismic information
• The CoRoT target HD49933: a possible seismic signature of heavy elements ionization in the deep convective zone
• PLATO Hare-and-Hounds exercise: Asteroseismic model fitting of main-sequence solar-like pulsators