"Figure 1: Brightness variations of Kepler stars with asteroseismically-determined surface gravities. The x-axis shows ""F8"", the brightness variation over granulation timescales. The y-axis is ""range"", the amplitude of variations. The symbol size shows ""X0"", what timescale variations are the most important (high X0 means shorter timescale variations, such as granulation, dominate). For low range stars, F8 correlates well with surface gravity (color scale)."