Magnetic activity properties of M-type kepler stars

In this paper, we study the magnetic activity properties for a sample of M-type stars in Kepler field by using the two light-curve-based magnetic proxies, iAC and Reff, which describe the periodicity and magnitude of light-curve variations, respectively. It is found that (1) stars with short rotational period might have a relatively large value of R¯eff (mean of Reff) while stars with long period can't have large R¯eff value; (2) there is a weak trend between the rotation period and the correlation of iAC and Reff, that is, the correlation of the two magnetic proxies tends to be positive for stars with shorter period and be zero and negative for stars with longer period; and finally (3) statistically speaking, the negative correlation stars can't have a large value of R¯eff as positive correlation stars. We describe the similarities and differences of magnetic activities, base on current and previous analysis, for M-type and G-type stars. The similarity of magnetic activity behaviors between M-type stars and G-type stars implies that the two kinds of stars obey the same magnetic dynamo mechanism, though their internal structures of the convective zone may be distinctly different.