Asteroseismology of Kepler red giant branch stars

We measure radial-mode frequencies from Kepler observations for 3642 solar-like oscillators on the red giant branch and use them to characterize the stars with grid-based modeling. We determine fundamental stellar parameters with good precision: the typical uncertainty is 4.5% for mass, 16% for age, 0.006dex for surface gravity, and 1.7% for radius.

We also achieve good accuracy for estimated masses and radii, based on a comparison with those determined for eclipsing binaries. We find a systematic offset of ~15% in mass and ~7% in radius between the modeling solutions and the scaling relations. Further investigation indicates that these offsets are mainly caused by a systematic bias in the {Delta}{nu} scaling relation: the original scaling relation underestimates the {Delta}{nu} value by ~4%, on average, and it is important to correct for the surface term in the calibration.