Toward a Better Understanding of Convectively-Driven Flicker in Kepler Light Curves

The light curves produced by the Kepler mission demonstrate real, stochastic brightness fluctuations (or "flicker") which impose a limit to the sensitivity of exoplanet detection and characterization methods. The sources of this brightness variation can include convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. In this work we focus on better characterizing the flicker component due to convective granulation, present in all Kepler stars with outer convective envelopes. Past work has extracted the convective flicker component of cool, low-mass Kepler stars, and additional past work has compared the amplitude of this variability component to the predictions of theoretical models and derived an empirical correction factor for these models motivated by the magnetic activity and shallow convection zones of F-dwarf stars. In this work we draw upon an expanded database of Kepler star convective flicker measurements, including a substantive sample of cool, giant stars, and we present an updated comparison of observations of convectively-driven flicker to theoretical predictions. A better understanding of convective flicker will better characterize a source of noise in exoplanet detection and characterization as well as better inform models of stellar granulation.