Conaire Deagan

Mapping stellar surfaces with high-precision astrometry

Mapping stellar surfaces is important for understanding stellar activity and its implications. Accurate localisation and temporal tracking of large-scale magnetic surface features, such as starspots and plages, can provide insights into stellar dynamos, differential rotation, and other phenomena. Traditionally, stellar surface mapping has relied on interferometry or light curve inversion techniques. However, recent work has demonstrated fundamental limitations in light curve inversion methods, including the ability to model any light curve with a two-spot model and the retrieval of, at best, only 50% of the surface information—often much less. This work demonstrates that high-precision astrometry offers a superior alternative for stellar surface mapping of nearby stars. Our approach not only yields more comprehensive information about stellar surfaces but also achieves finer “resolution” compared to traditional methods. This new mapping technique can improve our understanding of stellar activity and evolution, paving the way for more accurate models of stellar behaviour and structure.