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Chromospheric emission of solar-type stars with asteroseismic ages
Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avis › Tidsskriftartikel › Forskning › peer review
- R. S. Booth, Queen's University Belfast ,
- K. Poppenhaeger, Queen's University Belfast, University of Potsdam ,
- C. A. Watson, Queen’s University Belfast ,
- V. Silva Aguirre
- D. Stello
- H. Bruntt, Aarhus Katedralskole, Skolegyde 1, D-8000 Aarhus C, Denmark
Stellar magnetic activity decays over the main-sequence life of cool
stars due to the stellar spin-down driven by magnetic braking. The
evolution of chromospheric emission is well studied for younger stars,
but difficulties in determining the ages of older cool stars on the main
sequence have complicated such studies for older stars in the past.
Here, we report on chromospheric Ca II H and K line measurements for 26
main-sequence cool stars with asteroseismic ages older than a gigayear
and spectral types F and G. We find that for the G stars and the cooler
F-type stars that still have convective envelopes the magnetic activity
continues to decrease at stellar ages above 1 Gyr. Our magnetic activity
measurements do not show evidence for a stalling of the magnetic braking
mechanism, which has been reported for stellar rotation versus age for
G- and F-type stars. We also find that the measured R^' }_{ HK}
indicator value for the cool F stars in our sample is lower than
predicted by common age-activity relations that are mainly calibrated on
data from young stellar clusters. We conclude that, within individual
spectral type bins, chromospheric magnetic activity correlates well with
stellar age even for old stars.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Monthly Notices of the Royal Astronomical Society |
| Vol/bind | 491 |
| Nummer | 1 |
| Sider (fra-til) | 455-467 |
| Antal sider | 13 |
| ISSN | 0035-8711 |
| DOI | |
| Status | Udgivet - jan. 2020 |
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