LBA observations for project V622 semester 2022OCTS

In 2020 we successfully observed radio emission from both components of the flare dwarf binary GJ65 (UV & BL Ceti) with the LBA. Combined with state-of-the-art astrometry from ESO's VLTI GRAVITY interferometer, we were able to determine the position of the star with great accuracy and precision, and therefore the distance of the radio emission from the stellar photosphere. We are proposing to re-observe this and two additional active, nearby M-dwarf binary systems that are scheduled to be observed as priority astrometry targets on the GRAVITY Guaranteed Time Observation list. The targets suitable for LBA observations are GJ65, GJ799, and GJ1005. M-dwarfs are associated with the majority of exoplanets detected to date and as such they provide insights into habitability around these stars, being exposed to extreme space weather environments due to enhanced stellar activity. We are requesting 10h per target, for a total of 30h with the full LBA array. Detecting emission from these active M dwarfs similar to what we observed on GJ65, combined with GRAVITY astrometry could change our understanding of the magnetic and plasma environments around M dwarfs, providing constraints on the modelling of the spatial distribution of radio emitting electrons. These objects, due to their positions, can only be observed at length using the LBA by virtue of the low latitude of this array. This synergy of infrared and radio interferometry is unique in its ability to probe the structure of coronal environments of nearby stars.