The hot corino-like properties of four FUor-type eruptive young stars

The chemical composition of planets is determined by the material they accrete from the midplane of their parent disks.  Thus, understanding the chemical evolution of protostellar/protoplanetary disks is paramount for the study of planet formation. The detection of complex molecules is attainable in the youngest protostars due to their elevated temperatures. However, as the protostars evolve and their disks become colder, the molecules freeze onto the dust grains, becoming harder to detect as evidenced by the low number of Class I and II YSOs with detections of organic molecules. Therefore, the chemical evolution of the protostar, from Class 0 to Class III, remains a mystery. FU Orionis-type objects (FUors) are low-mass young stellar objects experiencing brief periods of enhanced mass accretion rates, which cause an increase in the disk temperature, and, thus, desorb the frozen molecules, making them easier to be detected by current facilities. FUor-type events typically occur in Class I/II objects, i.e. the evolutionary stages when planets are formed, presenting a great opportunity to analyze the chemical composition of disks as they are feeding gas and dust to the protoplanets. Here we present serendipitous detections of complex organic molecules around four FUor-type objects: L1551 IRS 5, Haro 5a IRS, OO Ser and V346 Nor. The detected molecules, their temperatures and the size of their emitting regions indicate that all four FUors are similar to hot corinos. We calculated the abundances with respect to methanol, and compared with other young stellar objects that are not in outburst and in different stages of stellar evolution. We will discuss similarities and differences between FUors and quiescent sources to see what is the role that outbursts have in the overall picture of chemical evolution. Finally, we will show how these and other less powerful eruptive young stars can provide information on the chemical evolution of protostars.