A SUBMILLIMETER-WAVE FLARE FROM GG TAURI

We have monitored the millimeter and submillimeter emission from the y oung stellar object GG Tau, a T Tauri binary system surrounded by a ma ssive circumbinary disk. We find that between 1992 and 1994, the flux has increased significantly at 800, 1100, and 1300 mu m, resulting in a steepening of the observed spectral energy distribution at those wav elengths. Such an increase appears consistent with a modest increase i n disk luminosity (a factor of 2). The increase in the effective disk temperature might arise from a slight change in the disk heating proce sses. Alternatively, the flux increase may reflect a sudden change in the underlying dust optical properties.