We present a complete atomic model for Si I line synthesis. We study how the computed profiles of two blue lines of this atom are influenced by the choice of the atomic parameters and find that, although several cross ...

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 ...

M stars are ideal targets to search for Earth-like planets. However, they usually have high levels of magnetic activity, which could affect their habitability and make difficult the detection of exoplanets orbiting around ...

We have built different models for stars of the same spectral type than the Sun but with different levels of chromospheric activity, to study the response of the S index of activity built from the emission of the Ca II ...

Context: The IUE database provides a large number of UV high and low-resolution spectra   of RS CVn-type stars from 1978 to 1996. In particular, many of these stars were monitored  continuously during several seasons by ...

Context.The main chromospheric activity indicator is the S index, which is the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied for stars from F to K. Another chromospheric ...

Stellar radiation from X-rays to the visible provides the energy thatcontrols the photochemistry and mass loss from exoplanet atmospheres.The important extreme ultraviolet (EUV) region (10-91.2 nm) isinaccessible and should ...

We present a detailed analysis of seven young stars observed with the spectrograph SOPHIE at the Observatoire de Haute-Provence for which the chemical composition was incomplete or absent in the literature. For five stars, ...

I present chromospheric-activity measurements of ~670 F, G, K, and M main-sequence stars in the Southern Hemisphere, from ~8000 archival high-resolution echelle spectra taken at Las Campanas Observatory since 2004. These ...