A Granulation "Flicker"-based Measure of Stellar Surface Gravity

TL;DR

This paper refines a method to measure stellar surface gravity using flicker signals in high-quality light curves, improving calibration and expanding its applications for stellar characterization in space missions.

Contribution

It updates and calibrates the flicker-based surface gravity measurement technique with a larger asteroseismic dataset and details the extraction process and limitations.

Findings

Calibrated flicker against a robust set of asteroseismic gravities.

Provided flicker-based logg values for 27,628 Kepler stars.

Enhanced understanding of flicker measurement limitations.

Abstract

In Bastien et al. (2013) we found that high quality light curves, such as those obtained by Kepler, may be used to measure stellar surface gravity via granulation-driven light curve "flicker". Here, we update and extend the relation originally presented in Bastien et al. (2013) after calibrating flicker against a more robust set of asteroseismically derived surface gravities. We describe in detail how we extract the flicker signal from the light curves, including how we treat phenomena, such as exoplanet transits and shot noise, that adversely affect the measurement of flicker. We examine the limitations of the technique, and, as a result, we now provide an updated treatment of the flicker-based logg error. We briefly highlight further applications of the technique, such as astrodensity profiling or its use in other types of stars with convective outer layers. We discuss potential uses in current and upcoming space-based photometric missions. Finally, we supply flicker-based logg values, and their uncertainties, for 27 628 Kepler stars not identified as transiting-planet hosts, with 4500<teff<7150 K, 2.5<logg<4.6, Kepler magnitude <13.5, and overall photometric amplitudes <10 parts per thousand.