Abstract
The theoretical oscillation frequencies of even the best asteroseismic models of solar-like oscillators show significant differences from observed oscillation frequencies. Structure inversions seek to use these frequency differences to infer the underlying differences in stellar structure. While used extensively to study the Sun, structure inversion results for other stars have so far been limited. Applying sound speed inversions to more stars allows us to probe stellar theory over a larger range of conditions, as well as look for overall patterns that may hint at deficits in our current understanding. To that end, we present structure inversion results for 12 main-sequence solar-type stars with masses between 1 and 1.15 M ⊙. Our inversions are able to infer differences in the isothermal sound speed in the innermost 30% by radius of our target stars. In half of our target stars, the structure of our best-fit model fully agrees with the observations. In the remainder, the inversions reveal significant differences between the sound speed profile of the star and that of the model. We find five stars where the sound speed in the core of our stellar models is too low and one star showing the opposite behavior. For the two stars in which our inversions reveal the most significant differences, we examine whether changing the microphysics of our models improves them and find that changes to nuclear reaction rates or core opacities can reduce, but do not fully resolve, the differences.
Original language | English |
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Article number | 198 |
Number of pages | 18 |
Journal | The Astrophysical Journal |
Volume | 961 |
Issue number | 2 |
Early online date | 26 Jan 2024 |
DOIs | |
Publication status | Published - 1 Feb 2024 |
Bibliographical note
AcknowledgmentsWe thank the anonymous referee for the constructive feedback that improved the manuscript considerably. The research leading to the presented results has received funding from the ERC Consolidator Grant DipolarSound (grant agreement No. 101000296). S.B. acknowledges NSF grant AST-2205026. S.B. would also like to thank the Heidelberg Institute of Theoretical Studies for their hospitality during the early days of this project. This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission Directorate. In addition, this work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC; https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. We have also used the gaia-kepler.fun crossmatch database created by Megan Bedell.
Facilities: Kepler - The Kepler Mission, Gaia - .
Keywords
- Stellar oscillations
- Stellar structures
- Stellar evolutionary models
- Stellar physics
- Low mass stars