Variation in the frequency separations with activity and impact on stellar parameter determination

TL;DR

This paper investigates how frequency separations in asteroseismology vary with stellar activity cycles and how these variations affect the accuracy of determining stellar parameters like radius, mass, and age.

Contribution

It analyzes the impact of activity-related frequency variations on stellar parameter estimation, highlighting differences observed in the Sun during different activity phases.

Findings

Fitted solar age varies by about 0.2 Gyr between activity phases.

Solar radius estimates are about 0.5% lower during minimum activity.

Frequency separation variations influence stellar parameter accuracy.

Abstract

Frequency separations used to infer global properties of stars through asteroseismology can change depending on the strength and at what epoch of the stellar cycle the p-mode frequencies are measured. In the Sun these variations have been seen, even though the Sun is a low-activity star. In this paper, we discuss these variations and their impact on the determination of the stellar parameters (radius, mass and age) for the Sun. Using the data from maximum and minimum activity, we fitted an age for the Sun that differs on average by 0.2 Gyr: slightly older during minimum activity. The fitted radius is also lower by about 0.5% for the solar effective temperature during minimum.