Asteroseismic constraints on active latitudes of solar-type stars: HD173701 has active bands at higher latitudes than the Sun

Research output: Contribution to journalArticle

Colleges, School and Institutes

Abstract

We present a new method for determining the location of active bands of latitude on solar-type stars, which uses stellar-cycle-induced frequency shifts of detectable solar-like oscillations. When near-surface activity is distributed in a non-homogeneous manner, oscillation modes of different angular degree and azimuthal order will have their frequencies shifted by different amounts. We use this simple concept, coupled to a model for the spatial distribution of the near-surface activity, to develop two methods that use the frequency shifts to infer minimum and maximum latitudes for the active bands. Our methods respond to the range in latitude over which there is significant magnetic flux present, over and above weak basal ephemeral flux levels. We verify that we are able to draw accurate inferences in the solar case, using Sun-as-a-star helioseismic data and artificial data. We then apply our methods to Kepler data on the solar analogue HD173701, and find that its active bands straddle a much wider range in latitude than do the bands on the Sun.

Bibliographic note

13 pages, 15 figures, MNRAS accepted

Details

Original languageEnglish
Pages (from-to)3857–3868
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume485
Issue number3
Early online date20 Mar 2019
Publication statusPublished - 1 May 2019

Keywords

  • astro-ph.SR, asteroseismology, stars: activity, stars: individual