Signatures of Magnetic Activity in the Seismic Data of Solar-type Stars Observed by Kepler

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Santos, ARG (Author) Other; Campante, TL (Author) FCUP; Chaplin, WJ (Author) Other; Cunha, MS (Author) FCUP; Lund, MN (Author) Other; Kiefer, R (Author) Other; Salabert, D (Author) Other; Garcia, RA (Author) Other; Davies, GR (Author) Other; Elsworth, Y (Author) Other; Howe, R (Author) Other

Journal

Title: Astrophysical Journal, Supplement Series

Vol. 237

Final page: 17

ISSN: 0067-0049

Publisher: American Astronomical Society

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 15 Citations

Other information

Authenticus ID: P-00P-2KD

DOI: 10.3847/1538-4365/aac9b6

Abstract (EN): In the Sun, the frequencies of the acoustic modes are observed to vary in phase with the magnetic activity level. These frequency variations are expected to be common in solar-type stars and contain information about the activity-related changes that take place in their interiors. The unprecedented duration of Kepler photometric time-series provides a unique opportunity to detect and characterize stellar magnetic cycles through asteroseismology. In this work, we analyze a sample of 87 solar-type stars, measuring their temporal frequency shifts over segments of 90 days. For each segment, the individual frequencies are obtained through a Bayesian peak-bagging tool. The mean frequency shifts are then computed and compared with: (1) those obtained from a cross-correlation method; (2) the variation in the mode heights; (3) a photometric activity proxy; and (4) the characteristic timescale of the granulation. For each star and 90-day sub-series, we provide mean frequency shifts, mode heights, and characteristic timescales of the granulation. Interestingly, more than 60% of the stars show evidence for (quasi-)periodic variations in the frequency shifts. In the majority of the cases, these variations are accompanied by variations in other activity proxies. About 20% of the stars show mode frequencies and heights varying approximately in phase, in opposition to what is observed for the Sun.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 19