Asteroseismology of 16000 Kepler Red Giants: Global Oscillation Parameters, Masses, and Radii.
2018
The
Keplermission has provided exquisite data to perform an ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize
solar-like oscillationsand granulation for 16,094 oscillating
red giants, using end-of-mission long-cadence data. We produced a homogeneous catalog of the frequency of maximum power (typical uncertainty $\sigma_{\nu_{\rm max}}$=1.6\%), the mean large
frequency separation($\sigma_{\Delta\nu}$=0.6\%), oscillation amplitude ($\sigma_{\rm A}$=4.7\%), granulation power ($\sigma_{\rm gran}$=8.6\%), power excess width ($\sigma_{\rm width}$=8.8\%), seismically-derived stellar mass ($\sigma_{\rm M}$=7.8\%), radius ($\sigma_{\rm R}$=2.9\%), and thus
surface gravity($\sigma_{\log g}$=0.01 dex). Thanks to the large
red giantsample, we confirm that
red-giant-branch(RGB) and helium-core-burning (HeB) stars collectively differ in the distribution of oscillation amplitude, granulation power, and width of power excess, which is mainly due to the mass difference. The distribution of oscillation amplitudes shows an extremely sharp upper edge at fixed $\nu_{\rm max}$, which might hold clues to understand the excitation and damping mechanisms of the oscillation modes. We find both oscillation amplitude and granulation power depend on metallicity, causing a spread of 15\% in oscillation amplitudes and a spread of 25\% in granulation power from [Fe/H]=-0.7 to 0.5 dex. Our asteroseismic stellar properties can be used as reliable distance indicators and age proxies for mapping and dating galactic
stellar populationsobserved by
Kepler. They will also provide an excellent opportunity to test
asteroseismologyusing Gaia
parallaxes, and lift degeneracies in deriving atmospheric parameters in large spectroscopic surveys such as APOGEE and
LAMOST.
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