  I study some aspects of common envelope evolution, where a compact star
enters the envelope of a giant star. I show that in some binary systems under a
narrow range of parameters, a substantial fraction of the giant stellar
envelope is lost before the onset of the common envelope. The reduced envelope
mass at the onset of the common envelope implies that the binary system emerges
from the common envelope with a relatively large orbital separation. I
therefore caution against a simple treatment, which omits this process, in the
study of systems that evolved through a common envelope phase and ended with a
relatively large orbital separation, e.g., PG1115+166. A fraction of the
envelope that is lost while the companion is still outside the giant stellar
envelope is accreted by the companion. The companion may form an accretion disk
and blow two jets. I propose this scenario for the formation of the bipolar
planetary nebula NGC 2346, which has a binary nucleus with an orbital period
longer than that of any other known binary system in planetary nebulae. Because
this scenario, of a late common envelope phase, occurs for a narrow range of
parameters, I expect it to be applicable to a small, but non-negligible, number
of systems.
