An Interacting Binary System Powers Precessing Outflows of an Evolved Star

Abstract

Stars are generally spherical, yet their gaseous envelopes often appear non-spherical when ejected near the end of their lives. This quirk is most notable during the planetary nebula phase when these envelopes become ionized. Interactions among stars in a binary system are suspected to cause the asymmetry. In particular, a precessing accretion disk around a companion is believed to launch point-symmetric jets, as seen in the prototype Fleming 1. Our discovery of a post common-envelope binary nucleus in Fleming 1 confirms that this scenario is highly favorable. Similar binary interactions are therefore likely to explain these kinds of outflows in a large variety of systems.Planetary nebulae (PNe) are thought to represent the transitory phase of the end of the lives of solar-like stars. The mass-loss mechanisms at play during the late stages of stellar evolution that produce the observed shapes of planetary nebulae have been a matter of debate in the last two decades (1). The leading paradigm to produce the most extreme nebular morphologies is evolution in an interacting binary system (2-4), in particular common-envelope (CE) evolution -the dramatic outcome of unstable mass transfer resulting in a binary system with a greatly reduced orbital period (P<~1 day for PNe). Despite recent detections of multiple post common-envelope binary central stars (5-7), there are as yet no clear-cut examples of binaries actively shaping their surrounding planetary nebulae. A handful of post-CE nebulae are known to be oriented in agreement with the orbital inclination of the binaries that ejected them (8) -as would be expected. However, we do not yet have any inkling how a particular binary configuration gives rise to a specific fundamental nebula shape. An alternative approach to tackle this difficult

Detection of a multishell planetary nebula around the hot subdwarf O-type star 2MASS J19310888+4324577

“…In fact, PNe with multiple structures at different orientations, such as quadrupolar or multipolar ones, are usually interpreted invoking a binary central star (e.g., Manchado et al 1996;Guerrero et al 2013, and references therein). In this respect, the structure of PN G 075.9+11.6 and the binary nature of 2M1931+4324 (Jacoby et al 2012) provide support for a binary star scenario in multishell PNe and reinforce the idea that binary stars are an important ingredient in the formation of complex PNe (De Marco 2009, and references therein; Miszalski et al 2009;Miszalski 2012;Boffin et al 2012).…”

“…Nevertheless, very large changes in orientation of the collimating agent would still be required. In any case, PN G 075.9+11.6 and its binary central star 2M1931+4324 present characteristics that make this system another interesting case for studying the formation of PNe with binary central stars, as, e.g., ETHOS 1 and Fleming 1 (Miszalski et al 2011;Boffin et al 2012).…”

The jet feedback mechanism (JFM) in stars, galaxies and clusters

“…The connection between the presence of jets (or collimated polar outflows) in PNe (and in pre-PNe) and the progenitor being in a binary system has received a huge support in the last decade (e.g., Miszalski et al 2009;Raga et al 2009;Witt et al 2009;Corradi et al 2011a,c;Miszalski et al 2011;Velázquez et al 2011;Boffin et al 2012;Miszalski et al 2013;Corradi et al 2014b;Tocknell et al 2014;Akras et al 2015;Chen et al 2016, to list a small fraction of the relevant studies). Not only white dwarf and main sequence stellar companions can shape PNe, but brown dwarfs and massive planets can play a non-negligible role as well (e.g., Soker 1996; De Marco & Soker 2011;Staff et al 2016b).…”

On the production of He, C, and N by low- and intermediate-mass stars: a comparison of observed and model-predicted planetary nebula abundances

“…According to Boffin et al (2012), Fg1 has a period of 1.2d. NGC 6826 has a fast rotating central star, which is something that can only be achieved in a merger (De Marco et al 2015).…”