Multiple and changing cycles of active stars II. Results
Abstract
We study the time variations of the cycles of 20 active stars based on decades-long photometric or spectroscopic observations. A method of time-frequency analysis, as discussed in a companion paper, is applied to the data. Fifteen stars definitely show multiple cycles; the records of the rest are too short to verify a timescale for a second cycle. The cycles typically show systematic changes. For three stars, we found two cycles in each of them that are not harmonics, and which vary in parallel, indicating that a common physical mechanism arising from a dynamo construct. The positive relation between the rotational and cycle periods is confirmed for the inhomogeneous set of active stars. Stellar activity cycles are generally multiple and variable.
Keywords
Cite
@article{arxiv.0904.1747,
title = {Multiple and changing cycles of active stars II. Results},
author = {K. Oláh and Z. Kolláth and T. Granzer and K. G. Strassmeier and A. F. Lanza and S. Järvinen and H. Korhonen and S. L. Baliunas and W. Soon and S. Messina and G. Cutispoto},
journal= {arXiv preprint arXiv:0904.1747},
year = {2015}
}
Comments
Accepted to Astronomy and Astrophysics