Relations between global seismic parameters and activity cycles of the Sun

Abstract

It is suggested that the dependency of the global asteroseismic parameters on stellar properties such as magnetic activity is carefully calibrated with a homogenous data sample in stellar parameters in the sense that the empirical scaling relations of the global asteroseismic parameters are used in estimating fundamental stellar properties. As an effort of examining the acoustic oscillations of very close stars in stellar parameters except the magnetic activity level, here, we explore the solar p-mode oscillations over the period from 1996 to 2014 covering the solar cycles 23 and the first half of 24 by analyzing photometric Sun-as-a-star data observed from the GREEN channel of the VIRGO/SPM instrument on board SoHO. By dividing the whole time series of observations into 19 segments of 1-year and calculating the corresponding power spectrum, we calculate the Spearman’s rank correlation coefficient with the chance probability between temporal variations of the global asteroseismic parameters and the solar 10.7-cm radio flux. As a result, we have confirmed earlier findings that the envelope amplitude and solar activity are negatively correlated. The envelope width has been found to show a correlation with the solar activity. We also note temporal variations on timescales shorter than ∼ 11 years in the envelope amplitude and width. As for the frequency of the maximum height in the acoustic power spectrum, the speculated correlation with solar activity has been reproduced. We have, finally, attempted to explore temporal variations of the background red-noise using a simple power-law and found that it appears to become steeper at solar minimum than at solar maximum.