The Proto-Planetary Nebula M1-92 and the Symbiotic Star MWC 560: Two Evolutionary Phases of the Same Type of Object?

Important similarities between the objects M1-92, a proto-planetary nebula of bipolar morphology, and MWC 560, a symbiotic star with a jet, have been found. A brief review of the previous studies for both objects is presented for the purpose of proposing mechanisms that best explain these similarities, since up to now both objects have been studied independently. From the comparison of the spectra of both objects, the existence of a jet is confirmed for the proto-planetary nebula M1-92, as well as its binary nature and the existence of a circumnuclear disk. Finally, an evolutionary sequence is proposed for the two objects where M1-92 is ~900 yr more evolved than MWC 560.