Multicolor Variability of Young Stars with Disks: Insights from Coordinated Space and Ground Observations

Space telescopes have provided unprecedented depictions of the manifold variability behaviors typical of young stellar objects (YSOs). However, the lack of coordinated, multiband data often limited our understanding of the observed flux patterns. We conducted a comprehensive variability survey of 278 B-to-K YSOs in the 1-2 Myr-old cluster NGC 6530. Our sample was monitored with Kepler/K2, and simultaneous u,g,r,i,Halpha time series were acquired with VST/OmegaCAM. We detected substantially lower variability on B/A stars than on G/K stars for any light curve morphology, and a dearth of some distinctive disk-driven behaviors among stars earlier than G. We could also pinpoint distinct contributions to the leading day-to-week variability timescales, from intense accretion triggered by inner disk instabilities, to variable accretion efficiency in the outer magnetosphere. On the heels of that project, we are undertaking a new survey of the Taurus star forming region, coupling high-precision photometry from TESS with simultaneous u,g,r,i data from the Las Cumbres Observatory. This program will provide unique constraints on the physical drivers of YSO variability, and on the mid- to long-term stability of inner disks around young stars.