VLBI Astrometry
Very Long Baseline Interferometry (VLBI) is a powerful technique in radio astronomy that allows astronomers to observe celestial objects using radio telescopes separated by hundreds or even thousands of kilometers. By combining the signals recorded at each telescope, it becomes possible to computationally reconstruct images with extremely high angular resolution. In fact, VLBI offers the highest angular resolution of any technique in astronomy. Its capabilities were spectacularly demonstrated by the Event Horizon Telescope, which captured groundbreaking images of nearby supermassive black holes. In addition to imaging, VLBI enables ultra-precise measurements of celestial positions—known as astrometry. Such measurements are essential across nearly all fields of astrophysics, from planet and star formation to cosmology.
Following a series of pioneering observations with the Very Long Baseline Array (VLBA) that demonstrated the astrometric power of VLBI when applied to young stars, we launched a large-scale program known as GOBELINS (Gould's Belt Distances Survey). This project focused on dozens of young stars spread across five nearby star-forming regions: Ophiuchus, Taurus, Perseus, Orion, and Serpens. For each target, we measured both the trigonometric parallax and proper motion with an accuracy better than 50 microarcseconds—comparable to that of the Gaia satellite and corresponding to relative distance uncertainties of about 1%. Within our sample, we also identified many tight binary systems, for which we were able to determine individual stellar masses with high precision. Learn more about GOBELINS by following the link below.
