# Linear approximation of seismic inversions: new kernels and structural effects

## TL;DR

This paper investigates the limitations of linear seismic inversion techniques for stars, highlighting how uncertainties in stellar parameters and micro-physics affect the validity of these methods.

## Contribution

It provides an analysis of the validity of linear assumptions in seismic inversions for stars, considering various structural pairs and the impact of model uncertainties.

## Key findings

- Uncertainties in stellar radius significantly affect nondimensional structural variables.
- Micro-physics uncertainties impact the verification of linear relations.
- Including seismic constraints improves the linear relation satisfaction.

## Abstract

Thanks to the space-based photometry missions CoRoT and Kepler, we now benefit from a wealth of seismic data for stars other than the sun. In the future, K2, Tess and Plato will provide further observations. The quality of this data may allow kernel-based linear structural inversion techniques to be used for stars other than the sun. To understand the limitations of this approach, we analyse the validity of the linear assumption used in these inversion techniques. We inspect various structural pairs and see how they are affected by structural changes. We show that uncertainties in radius strongly affect structural pairs of nondimensional variables, and that various other effects might come into play. Amongst these, the importance of micro-physics give the most striking example of how uncertainties in stellar models impact the verification of the linear relations. We also point out that including seismic constraints in the forward modelling fit helps with satisfying the linear relations.