1)FU Ori is a high mass accretion rate disk (2x10 -4 M ʘ yr -1 ) from 5 R  to 0.5-1 AU around a 0.3 M  star 2) Outbursts last ~100 yrs=>0.02 Msun t visc ~R 2 /ν = decay time α=0.02-0.2 3) Keplerian rotation disk Observation summary:
{}