Chromospheric models of solar analogues with different activity levels
Instituto de Astronomía y Física del Espacio, CC. 67 Suc. 28 (1428) Buenos Aires, Argentina e-mail: mariela@iafe.uba.ar
Received:
6
January
2005
Accepted:
24
April
2005
We computed chromospheric models of the Sun as a star and of nine solar
analogues. The atmospheric models were constructed to obtain the best possible match
with the Ca II K and Hβ lines, including the asymmetry of the lines due to
macroscopic velocity fields. The stars were chosen with 
(the solar 
) and have a wide variety of magnetic activity levels,
which allows us to study the differences in atmospheric
structures induced by activity.
For the less active stars we found that the changes with activity are in the region of
the temperature minimum, while the
most active stars show changes all along their
atmospheric structures, mainly in the upper chromosphere.
Regarding the macroscopic velocity fields, we can distinguish between the two groups.
The most active group has a velocity field in the temperature-minimum region, and the other
group in the chromospheric plateau. We also computed the net radiative losses
for each model, and found that they depend linearly on the usual index of
chromospheric activity, SCa II.
Key words: radiative transfer / stars: atmospheres / stars: activity
© ESO, 2005