Cycles of magnetic activity in solar-type stars. The place of the Sun among the stars with different levels of coronal and chromospheric activity

TL;DR

This study analyzes magnetic activity cycles in solar-type stars, revealing that cyclic activity varies with spectral class and positioning the Sun as a star with low chromospheric and coronal activity levels.

Contribution

It provides a comparative analysis of activity cycles across F, G, and K stars, highlighting the Sun's unique low activity levels among similar stars.

Findings

Cyclic activity is more prominent in K-stars.

The Sun has the lowest chromospheric activity among studied stars.

The Sun exhibits minimal coronal radiation and flux variations.

Abstract

The atmospheric activity of the Sun and solar-type stars is analysed involving observations from HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories, and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of F, G and K spectral classes, the cyclic activity, similar to the 11-yr Solar cycles, is different: it becomes more prominent in K-stars. Comparative study of solar-type stars with different levels of the chromospheric and coronal activity confirms that the Sun belongs to stars with the low level of the chromospheric activity and stands apart among these stars by the minimum level of the coronal radiation and minimum flux variations of the photospheric radiation.