Landing page for project EB102

The red dwarf WX UMa (M6.0Ve), also known as GJ 412B, is in a slow (>3kyr) orbit around GJ 412A (M1.0). Its variable radio emission is strongly (-62%) polarized in Stokes-V. We have detected the source in two EVN epochs, and in both cases, it has a significant positional offset (6.5 mas, 5 mas) compared to where it should be according to the astrometry published in Gaia DR3. We show that the offset cannot be due to phase referencing errors, the accuracy of the VLBI or Gaia astrometry, or the binary orbit. This persistent offset is well outside the expected coronal envelope of the star, and could indicate a possible unknown companion to the star. Continued observations of this source should confirm whether the location of the emission is indeed changing between epochs. Our observations will include polarization measurements to study the nature of the emission, and MultiView and in-beam references to achieve the highest possible astrometric accuracy.

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