Optical light curves of the FUor and FUor-like objects

For several decades we have been performing photometric monitoring of some of the star formation regions. We consider that the study of photometric variability of pre-main sequence stars is of great importance in understanding stellar evolution. Significant place in our program take observations of FUor and FUor-like objects. The FUor phenomenon is relatively rare but it is of great importance for the formation of young stars. During the outbursts, FUor objects undergo significant increase of accretion rate from the circumstellar disk onto the stellar surface.

In this presentation, we show the latest data from optical photometric studies of five FUors, one FUor-like and two intermediate objects with very large amplitudes. Our collection contains the following objects: V1735 Cyg, V733 Cep, V2493 Cyg (HBC 722), V582 Aur, V900 Mon, Parsamian 21, V1647 Ori and V2492 Cyg. Our monitoring is carried out in BVRI filters, which allows studying the variability in color indexes also. By comparing the historical light curves of these objects and adding other well-studied FUor objects, we try to classify them into several main groups.