An examination of some characteristics of Kepler Short and Long Cadence Data

TL;DR

This paper compares Kepler short- and long-cadence data, highlighting the advantages of short-cadence data for time resolution and frequency analysis, and discusses residual noise issues affecting asteroseismology.

Contribution

It provides a detailed comparison of Kepler short- and long-cadence data, revealing subtle differences and advantages of short-cadence data for stellar analysis.

Findings

Short-cadence data offer higher time resolution for short-lived events.

Short-cadence data have a higher Nyquist frequency.

Long-cadence data residuals show increased noise affecting asteroseismology.

Abstract

A close comparison of Kepler short- and long-cadence data released prior to 2011 Nov 1 has shown some subtle differences that make the short-cadence data superior to their long-cadence counterparts. The inevitable results of a faster sampling rate are present: the short-cadence data provide greater time resolution for short-lived events like flares, and have a much higher Nyquist frequency than the long-cadence data; however, they also contain fewer high-amplitude peaks at low frequency and allow a more precise determination of pulsation frequencies, amplitudes and phases. The latter observation indicates that Kepler data are not normally distributed. Moreover, a close inspection of the Pre-search Data Conditioned (PDC) long-cadence data show residuals that have increased noise on time-scales important to asteroseismology, but unimportant to planet searches.