ON CHROMOSPHERIC VARIATIONS MODELING FOR MAIN-SEQUENCE STARS OF G AND K SPECTRAL CLASSES

We present a method of chromospheric flux simulation for 13 late-type main-sequence stars. These Sun-like stars have well-determined cyclic flux variations similar to 11 yr solar activity cycle. Our flux prediction is based on chromospheric HK emission time series measurements from Mount Wil-son Observatory and comparable solar data. We show that solar three-component modeling explains well the stellar observations. We find that the 10 − 20 % of K- stars disc surfaces are occupied by bright active regions. KEY WORDS: late-type stars, chromospheric variations, modeling of chromospheric emission