The missing mass conundrum of post-common-envelope planetary nebulae
  Most planetary nebulae (PNe) show beautiful, axisymmetric morphologies
despite their progenitor stars being essentially spherical. Angular momentum
provided by a close binary companion is widely invoked as the main agent that
would help eject an axisymmetric nebula, after a brief phase of engulfment of
the secondary within the envelope of the Asymptotic Giant Branch (AGB) star,
known as a common envelope (CE). The evolution of the AGB would be thus
interrupted abruptly, its (still quite) massive envelope fully ejected to form
the PN, which should be more massive than a PN coming from the same star were
it single. We test this hypothesis by deriving the ionised+molecular masses of
a pilot sample of post-CE PNe and comparing them to a regular PNe sample. We
find the mass of post-CE PNe to be actually lower, on average, than their
regular counterparts, raising some doubts on our understanding of these
intriguing objects.
