Chromospheric changes in K stars with activity

Abstract

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<$0.90, including the widely studied Epsilon Eridani and a variety of magnetic activity levels. We computed chromospheric models for the stars in the sample, in most cases in two different moments of activity. The models were constructed to obtain the best possible match with the Ca II K and the H$\beta$ 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.

References in corpus (8)

• S4N: A Spectroscopic Survey of Stars in the Solar Neighborhood
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• Chemical abundances of planet-host stars: Results for alpha and Fe-group elements
• The Na I D resonance lines in main sequence late-type stars
• Mg II h + k emission lines as stellar activity indicators of main sequence F-K stars
• Carbon monoxide in the solar atmosphere II. Radiative cooling by CO lines
• Modelling the chromosphere and transition region of Epsilon Eri (K2 V)
• The corona and upper transition region of epsilon Eridani

Cited by in corpus (6)

• The FIP and Inverse FIP Effects in Solar and Stellar Coronae
• Semi-empirical Modeling of the Photosphere, Chromosphere, Transition Region, and Corona of the M-dwarf Host Star GJ 832
• A possible long-term activity cycle for ι Horologii: First results from the HKα & SPI-HKα projects
• Improvements in the determination of ISS Ca II K parameters
• Modelling chromospheric line profiles as diagnostics of velocity fields in ω Centauri red giant stars
• 12 Years of Stellar Activity Observations in Argentina