Speaker
Diego Lorenzo-Oliveira
(Universidade de São Paulo)
Description
It is well known that the magnetic activity of solar type stars decreases with age, but it is widely debated in the literature whether there is a smooth decline or if there is an early sharp drop until 1-2 Gyr followed by a relatively inactive and constant phase. We revisited the activity-age (AC) relation through Mount Wilson (MW) Ca II H & K activity indices. We measure the activity indices using HARPS time-series observations of 79 solar twins with precise isochronal ages and physical parameters. New relations between activity and age of solar twins were derived assessing the chromospheric age-dating limits using MW metric. The Ca II H & K AC relation of solar twins evolves until 6 Gyr, in agreement with previous findings using open clusters. This confirms that Ca II H & K lines remain an interesting clock also for stars slightly older than the Sun. We are extending this analysis exploring the flux-flux and AC relations using other optical chromospheric sensitive lines.
Primary author
Diego Lorenzo-Oliveira
(Universidade de São Paulo)
Co-authors
Fabrício Freitas
(Instituto de Astronomia, Geofísica e Ciências Atmosféricas - Universidade de São Paulo)
Jorge Meléndez
(Instituto de Astronomia, Geofísica e Ciências Atmosféricas - Universidade de São Paulo)
