Abstract
Planetary nebulae (PNe) represent a well defined stage of stellar evolution, where the characteristics of both, the central star and the gaseous envelope have defined properties. A large fraction of PNe contain binary nuclei, therefore, binary evolution plays an important role in the AGB and proto-planetary stages under certain circumstances. Symbiotic nebulae with extended envelopes (D-type), are identified with binary systems where the primary component is usually a Mira giant and the companion a hot white dwarf. Some of these systems resemble planetary nebulae and as a consequence can lead to misleading interpretations. Here we discuss some relevant links and differences between these two types of nebulae.
