Do long-cadence data of {\it Kepler} satellite capture the basic properties of flares ?

TL;DR

This study compares long-cadence and short-cadence Kepler data for stellar flares, finding that long-cadence data can capture basic flare properties despite underestimating energies and amplitudes.

Contribution

It provides a systematic comparison showing that long-cadence data, despite limitations, can still reflect the fundamental characteristics of stellar flares.

Findings

LC data underestimates flare energies by 25%

LC data underestimates flare amplitudes by 60%

LC data overestimates flare durations by 50%

Abstract

Flare research is becoming a burgeoning realm in the study of stellar activity due to the launch of {\it Kepler} in 2009. {\it Kepler} provides data with two time resolutions, i.e., the long-cadence (LC) data with a time resolution of 30 minutes and the short-cadence(SC) data with a time resolution of 1 minute, both of which can be used to study stellar flares. In this paper, we search flares in light curves with both LC data and SC data, and compare them in aspects of the true-flare rate, the flare energy, the flare amplitude, and the flare duration. It is found that LC data systematically underestimated the energies of flares by 25\%, and underestimated the amplitudes of flares by 60\% compared with SC flares. The duration are systematically overestimated by 50\% compared with SC flares. However, the above percentages are poorly constrained and there is a lot of scatter. About 60\% SC flares have not been detected by LC data. We investigate the limitation of LC data, and suggest that although LC data cannot reflect the detailed profiles of flares, they also can capture the basic properties of stellar flares.