Detection of binary and multiple systems among rapidly rotating K and M dwarf stars from Kepler data

TL;DR

This study analyzes Kepler data to identify rapidly rotating K- and M-dwarf stars, discovering multiple systems through periodicity analysis and imaging, which aids in understanding young stellar systems.

Contribution

It introduces methods to distinguish true multiple star systems from other light variations and confirms their physical association with multi-technique validation.

Findings

Approximately 50 stars show multiple incommensurate periods.

Multiple periodicities are independent and likely from different stars.

Validated multiple systems with imaging and pixel-level data analysis.

Abstract

From an examination of ~18,000 Kepler light curves of K- and M-stars we find some 500 which exhibit rotational periods of less than 2 days. Among such stars, approximately 50 show two or more incommensurate periodicities. We discuss the tools that allow us to differentiate between rotational modulation and other types of light variations, e.g., due to pulsations or binary modulations. We find that these multiple periodicities are independent of each other and likely belong to different, but physically bound, stars. This scenario was checked directly by UKIRT and adaptive optics imaging, time-resolved Fourier transforms, and pixel-level analysis of the data. Our result is potentially important for discovering young multiple stellar systems among rapidly rotating K- and M-dwarfs.