Landing page for project EG104

The recently discovered substellar triple system VHS1256-1257 consists in a 2x70 Mjup M7.5 binary dwarf and a 15 Mjup L7 companion placed only at 15pc. Previous VLA observations showed that the central dwarf binary displays detectable levels of emission, 60 microJy at X-band, suggesting that both high-rotation rates and strong magnetic fields play an active role in this system. Further VLA and EVN observations provided relevant information of the spectrum of this source, showing evidences that the radiation is self-absorbed at 1.4 GHz. We request sensitive C-band eVLBI observations of VHS1256-1257 to explore the presence of compact radio emission in the host M7.5 binary, which will be essential to 1) constrain the radiation mechanism acting in this ultracool dwarf, and 2) clarify if the radio emission comes from one or both components of the binary. This may uncover differences in the stellar rotation history and therefore different magnetic field configurations for each member of the central pair.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197