Chromospheric changes in K stars with activity

VIEYTES, M.; MAUAS, P.J.D.; DÍAZ, R. F.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Blackwell Publishing Ltd

Lugar: Oxford ; Año: 2009 vol. 398 p. 1495 - 1504

0035-8711

We study the differences in chromospheric structure induced in K stars by stellar activity, to expand our previous work for G stars, including the Sun as a star.We selected six stars of spectral type K with 0.82$<B!-!V<$0.90, including the widely studied Epsilon Eridani, which have a wide variety of magnetic activity levels. We computed chromospheric models for the stars in the sample, in most cases in two different moments of activity.The models were constructed to obtain the best possible match with the Ca II K and the Hbeta observed profiles. We also computed in detail the net radiative losses for each model to constrain the heating mechanism that can maintain the structure in the atmosphere. We find a strong correlation between these losses and Sc, the index generally used as a proxy for activity, as we found for G stars.