Uncovering the radio emission of low-mass systems

Abstract

Radio observations allow us to probe the nature of low mass objects, including ultracool dwarfs. Additionally, very long baseline interferometric observations provide the highest angular resolution in astronomy to date, which opens a window to measure dynamical masses of these objects in order to benchmark evolutionary models. We present here a multi-epoch, multi-frequency study of the substellar triple system VHS 1256−1257. We have found radio emission at 6 GHz and 33 GHz coincident with the expected position of the central binary of VHS 1256−1257. No emission is detected at higher frequencies (230 GHz and 345 GHz) nor at 5 GHz with VLBI arrays. The emission appears to be stable over almost 3 years at 6 GHz. These results can be well explained by non-thermal gyrosynchrotron emission originating at radiation belts present in both components and viewed equatorially. We also share preliminary results from our VLA observations of 5 low-mass binary systems and EVN observations of 4 ultracool dwarfs (including a binary).