Abstract
Close binary evolution is widely invoked to explain the formation of axisymmetric planetary nebulae after a brief common envelope phase. The evolution of the primary would be interrupted abruptly, its still quite massive envelope being fully ejected to form the PN, which should be more massive than a planetary nebula coming from the same star, were it single. We test this hypothesis by investigating the ionised and molecular masses of a sample consisting of 21 post-common-envelope planetary nebulae, roughly one-fifth of their known total population, and comparing them to a large sample of regular planetary nebulae (not known to host close-binaries). We find that post-common-envelope planetary nebulae arising from single-degenerate systems are, on average, neither more nor less massive than regular planetary nebulae, whereas post-common-envelope planetary nebulae arising from double-degenerate systems are considerably more massive and show substantially larger linear momenta and kinetic energy than the rest. The reconstruction of the common envelope of four objects further suggests that the mass of single-degenerate nebulae actually amounts to a very small fraction of the envelope of their progenitor stars. This leads to the uncomfortable question of where the rest of the envelope is, raising serious doubts on our understanding of these intriguing objects.
Highlights
Planetary nebulae (PNe) display beautiful, complex morphologies often showing high degrees of symmetry, mostly elliptical or bipolar
In order to overcome the clear limitation that this transition is usually not optically thin, we introduce a correction factor for the underestimated masses resulting from J = 2−1 transitions in order to match masses found via the J = 1−0 transition in a sample of PNe in which both transitions are available in the literature [14,15,16,17]
Our results indicate that post-common envelope (CE) PNe hosting SD systems seem, on average, neither more nor less massive than regular PNe, whereas post-CE PNe from DD systems seem considerably more massive than both groups
Summary
Planetary nebulae (PNe) display beautiful, complex morphologies often showing high degrees of symmetry, mostly elliptical or bipolar. In the case of a sufficiently close companion, the system undergoes a common envelope (CE) event when the primary star evolves along the giant branch(es), expanding before eventually overflowing its Roche lobe and engulfing its companion [4] In this very brief stage (∼1 year), the orbit of the secondary star quickly shrinks due to drag forces, providing an angular momentum for the system to eject the CE, which we will observe as a PN. Estimating the actual mass of post-CE PNe could help us gain a better understanding of the physics of CE ejection In this respect, it can be helpful to establish comparisons between these objects and the general population of PNe, encompassing nebulae arising from close binaries and from single stars and longer period binary stars that did not experience a CE. Please consult the main publication for additional details, information on the methods followed, and general discussion on the mass of post-CE PNe [12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
