Parametrizing the time-variation of the "surface term" of stellar p-mode frequencies: application to helioseismic data

Abstract

The solar-cyle variation of acoustic mode frequencies has a frequency dependence related to the inverse mode inertia. The discrepancy between model predictions and measured oscillation frequencies for solar and solar-type stellar acoustic modes includes a significant frequency-dependent term known as the surface term that is also related to the inverse mode inertia. We parametrize both the surface term and the frequency variations for low-degree solar data from Birmingham Solar-Oscillations Network (BiSON) and medium-degree data from the Global Oscillations Network Group (GONG) using the mode inertia together with cubic and inverse frequency terms. We find that for the central frequency of rotationally split multiplets the cubic term dominates both the average surface term and the temporal variation, but for the medium-degree case the inverse term improves the fit to the temporal variation. We also examine the variation of the even-order splitting coefficients for the medium-degree data and find that, as for the central frequency, the latitude-dependent frequency variation, which reflects the changing latitudinal distribution of magnetic activity over the solar cycle, can be described by the combination of a cubic and an inverse function of frequency scaled by inverse mode inertia. The results suggest that this simple parametrization could be used to assess the activity-related frequency variation in solar-like asteroseismic targets.

arXiv comment13 pages, 11 figures. Accepted by MNRAS 13 October 2016

References in corpus (10)

• CoRoT reveals a magnetic activity cycle in a Sun-like star
• A new correction of stellar oscillation frequencies for near-surface effects
• Performance of the Birmingham Solar-Oscillations Network (BiSON)
• Solar-cycle variation of the sound-speed asphericity from GONG and MDI data 1995-2000
• Solar Cycle Related Changes at the Base of the Convection Zone
• BiSON data preparation: A correction for differential extinction and the weighted averaging of contemporaneous data
• Comparison of Ground- and Space-based Longitudinal Magnetograms
• The acoustic cut-off frequency of the Sun and the solar magnetic activity cycle
• Validation of solar-cycle changes in low-degree helioseismic parameters from the Birmingham Solar-Oscillations Network
• Modeling the Asteroseismic Surface Term across the HR Diagram

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• The robustness of asteroseismic estimates of global stellar parameters to surface term corrections
• Influence of magnetic activity on the determination of stellar parameters through asteroseismology
• Asteroseismic constraints on active latitudes of solar-type stars: HD173701 has active bands at higher latitudes than the Sun
• Impact of magnetic activity on inferred stellar properties of main sequence Sun-like stars
• Changes in the sensitivity of solar p-mode frequency shifts to activity over three solar cycles
• Imprint of the magnetic activity cycle on solar asteroseismic characterisation based on 26 years of GOLF and BiSON data
• Evidence of solar-cycle related structural changes in the solar convection zone
• Influence of the magnetic activity cycle on mean density and acoustic radius inversions
• Systematics in Asteroseismic Modelling: Application of a Correlated Noise Model for Oscillation Frequencies
• Asteroseismic Investigations of the Binary System HD176465
• Unexpected solar-cycle variation of acoustic mode power in Sun-as-a-star observations