A SEARCH FOR COLD DUST AROUND POST-T TAURI CANDIDATES

We have made 1.3 mm continuum observations of 15 age-dated post-T Taur i candidates that occur as secondaries in binary systems with a primar y of early spectral type (so-called Lindroos systems). Most of the obj ects have estimated ages of 10-100 Myr. None of the companions were de tected at 3 sigma upper limits ranging from 13-134 mJy. This implies u pper limits on the mass of cold circumstellar dust of similar to 8 10( -6)-3 10(-4)M.. The absence of dust emission suggests that the dust gr ains may have grown into planetesimals or planets, or they may have be en dispersed or accreted. Our observations put a limit on the lifetime of optically thin dusty disks of order 10(7) yr in these systems. Two primaries were also included in this survey, again with no detections .