Chemical impact of FUor outburst in embedded objects

FU Orionis-type objects (FUors), which experience sudden accretion outbursts, can be of two main types: evolved young stellar objects of Class II and earlier objects of Class I with embedding envelopes. Here we consider the impact of a FUor outburst on the chemical composition of protoplanetary disk and the envelope, paying special attention to CO molecule. We compare the results of astrochemical models with and without the envelope.