Halpha and the He I D3 lines as activity indicators

CINCUNEGUI, C. C.; MAUAS, P.J.D.

Argentina

Congreso; Boletín de la Asociación Argentina de Astronomía; 2005

Asociación Argentina de Astronomía

The index mostly used to measure chromospheric stellar activity is the one combining Ca II H and K line fluxes. These lines are not particularly adequate to study cool stars, which are intrinsically faint and red. In this work we present more than 800 observations of 108 cool dwarf stars obtained at the CASLEO. They range from 3900 to 6700 Å at a spectral resolution of R ~ 26400. We have simultaneous observations of Ca II, Halpha and He I D3 fluxes because the spectra are flux-calibrated. We use them to characterize possible activity indicators associated to longer wavelengths than the calcium