Scaling relations for width of the power excess of stellar oscillations

초록

Relations between global asteroseismic quantities allow us to derive fundamental stellar parameters. To obtain an insight into solar-like pulsators by an accurate estimate of stellar property requires to explore various scaling relations other than commonly-exploited ones as well as to calibrate the dependence of those over a range of metallicity, mass and evolutionary status of stars. We investigate statistical properties of the width of the Gaussian envelope delta nu(env) for the stellar oscillation power excess by analyzing light curves of 160 stars observed with short-cadence mode by Kepler. We consider the envelope width as important because it measures the efficiency of excitation and damping of solar-like oscillations due to the turbulence in the outer convective envelope. We attempt to fit a single slope power-law and a broken power-law to relations of delta nu(env) with nu(max) and Delta nu resulting from three different background models, each of which delineates the red-noise of the stellar power spectrum. A goodness of fit is provided in term of chi(2). In the case of a single slope fit the resulting slope ends up with delta nu(env)/mu Hz proportional to (nu(max)/mu Hz)(similar to 1.47) and delta nu(env)/mu Hz proportional to(Delta nu/mu Hz)(-1.83) on average, which is somewhat steeper than a previous outcome for red giants. Fitting with two distinct slopes at breaks of nu(max) similar to 850 mu Hz and Delta nu similar to 50 mu Hz, however, suits in the power-law fit than with a single slope in general. Direct fitting in nu(max) - n(env)plot yields the power-law index +0.53, apparently steeper than previously reported slope from red giants. The origin of breaks can be illustrated by the attributes in the delta nu(env)-distribution of main-sequence and sub-giant stars in the seismic H-R diagram.

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