Multi-color light curves of Ex Lup

Despite extensive monitoring that dates back 130yr, the accretion history of EX Lup remains mostly qualitative and has large uncertainties. We assess historical accretion rates of EX Lup by applying correlations between optical brightness and accretion, developed on multi-band magnitude photometry of the ~2mag optical burst in 2022.

Two distinct classes of bursts occur: major outbursts ({Delta}V~5mag) have year-long durations, are rare, reach accretion rates of dM/dt_acc_~10^-7^M_{sun}_/yr at peak, and have a total accreted mass of around 0.1 Earth mass. The characteristic bursts ({Delta}V~2mag) have durations of ~2-3 months, are more common, reach accretion rates of dM/dt_acc_~10^-8^M_{sun}_/yr at peak, and have a total accreted mass of around 10-3 Earth masses.