M dwarfs quasi-periodic pulsations at a time resolution of 1 s

TL;DR

This study reports the discovery of 13 new quasi-periodic pulsations in stellar flares of M dwarfs, with periods from 6 to 107 seconds, using high-resolution observations and advanced analysis methods.

Contribution

It provides the first detailed analysis of stellar QPPs in the tens-of-seconds range using 1-second resolution data, revealing new correlations with flare properties.

Findings

13 new QPPs detected in stellar flares

QPP periods range from 6 to 107 seconds

Significant correlations between QPP period and flare characteristics

Abstract

Quasi-periodic pulsations (QPPs) of Sun and stars are challenging for stellar flare models. The white light stellar QPPs in the periodicity region of tens of second are unexplored yet. On the basis of observations with the 6-m telescope BTA in U-band of flaring dM-stars EV Lac, Wolf 359, Wolf 424, V577 Mon and UV Ceti we found 13 new QPPs. This composes 30% occurrence among 44 worked flares. These QPPs were found to have periods ranging from 6 to 107 seconds and were detected using both Fourier transform and empirical mode decomposition methods. The observed QPPs were categorized by the evolution of their oscillation envelope and fractional flux amplitudes. There are shown the statistically significant correlations of the QPP period with the duration, the equivalent duration and the amplitude of a flare, and the correlation between the QPP amplitude and flare amplitude.