The proper motions of a source obtained at different epochs or in different
spectral regions should in principle be consistent. However, in the case of a
binary source or a source with associated ejecta, they could be different
depending on the epochs when the observations were made and on what emission is
traced in each spectral region. In this paper we determine the radio proper
motions of the ultra-cool dwarf binary VHS 1256β1257AB from Very Large Array
(VLA) observations, that we find are consistent within error (β2β3%)
with those reported by Gaia DR3. The comparison of the proper motions and the
analysis of the VLA data imply that, as in the optical, the radio emission is
coming in comparable amounts from both components of the unresolved binary.Comment: 8 pages, 3 figures. To appear in Revista Mexicana de Astronomia y
Astrofisic