# Seismic Signatures of Stellar Magnetic Activity -- What Can We Expect from TESS?

## TL;DR

This paper explores how TESS data can be used to detect stellar magnetic activity through seismic signatures, deriving a new scaling relation for activity-related frequency shifts and estimating the number of stars where these shifts can be observed.

## Contribution

It introduces a new scaling relation for acoustic frequency shifts due to stellar activity and predicts the potential yield of detectable signals with TESS.

## Key findings

- Significant p-mode frequency shifts are expected in hundreds of main-sequence and early subgiant stars.
- TESS can potentially detect activity-related seismic signatures in thousands of late subgiant and red giant stars.
- A new scaling relation links stellar activity amplitude to seismic frequency shifts.

## Abstract

Asteroseismic methods offer a means to investigate stellar activity and activity cycles as well as to identify those properties of stars which are crucial for the operation of stellar dynamos. With data from CoRoT and \textit{Kepler}, signatures of magnetic activity have been found in the seismic properties of a few dozen stars. Now, NASA's Transiting Exoplanet Survey Satellite (TESS) mission offers the possibility to expand this, so far, rather exclusive group of stars. This promises to deliver new insight into the parameters that govern stellar magnetic activity as a function of stellar mass, age, and rotation rate. We derive a new scaling relation for the amplitude of the activity-related acoustic (p-mode) frequency shifts that can be expected over a full stellar cycle. Building on a catalogue of synthetic TESS time series, we use the shifts obtained from this relation and simulate the yield of detectable frequency shifts in an extended TESS mission. We find that, according to our scaling relation, we can expect to find significant p-mode frequency shifts for a couple hundred main-sequence and early subgiant stars and for a few thousand late subgiant and low-luminosity red giant stars.