Difference frequencies of nonradial pulsation modes and repetitive outbursts in classical Be stars

TL;DR

This paper investigates the relationship between difference frequencies in nonradial pulsations and outburst phenomena in classical Be stars, suggesting slow pulsation variations may assist in stellar mass loss.

Contribution

It identifies and analyzes the role of low-frequency difference pulsations in classical Be stars and their possible connection to outburst events.

Findings

Difference frequencies can be as low as 0.03 c/d.

Slow pulsation variations may facilitate mass loss.

Frequency pairs often relate to stellar variability.

Abstract

Space photometry has revealed rich pulsation spectra in classical Be stars. Often frequency pairs can be found that differ by nearly the frequency of a third genuine stellar variability. The lowest currently known of these so-called difference (or $\Delta$) frequencies reach 0.03 c/d, which is the upper limit of outburst frequencies. The potential of such slow variations for pulsation-assisted mass loss is discussed.