Pulsation powered by deuterium burning in brown bwarfs and very-low-mass stars

TL;DR

This study investigates pulsations caused by deuterium burning in young brown dwarfs and very-low-mass stars, using a dedicated observational campaign to detect variability and explore their internal structures.

Contribution

It provides the first comprehensive survey of variability in young low-mass objects, testing the presence of deuterium-burning pulsations and analyzing rotation periods.

Findings

Detected variability on timescales from minutes to days.

Achieved sensitivity to millimagnitude amplitude oscillations.

Provided new data on rotation period distribution in young clusters.

Abstract

Pulsation powered by deuterium burning in brown dwarfs and very low mass stars has been put forth (Palla & Baraffe 2005) as a novel probe of the interiors of these objects in the 1-15 Myr age range. Previous observations have hinted at variability on the expected timescales of a few hours, suggesting but not confirming that the phenomenon is at work in young brown dwarfs. We have recently carried out a dedicated campaign to search for this putative class of pulsators among known low-mass members of five young star clusters. Our survey achieves sensitivity to periodic oscillations with photometric amplitudes down to several millimagnitudes. We present the census of variability over timescales ranging from minutes to days and discuss the current prospects for pulsation as a tool in the study of young, objects near the substellar boundary. As a byproduct, this work provides new insights into the distribution of stellar rotation periods at young ages via the detection of variability due to cool surface spots.