Jet creation in post-asymptotic giant branch binaries

Astrophysical jets are frequently observed phenomena in the Universe, ranging from high-energy jets in active galactic nuclei to low-energy stellar jets. Recent studies, have shown that jets are also present in a large fraction of binary post-asymptotic giant branch (post-AGB) systems. These are systems in which a post-AGB star and a main-sequence companion form a binary, that is surrounded by a circumbinary disk. The companion star itself is surrounded by a smaller accretion disk, from which a jet is launched. The jet-launching mechanisms and their physical structure are currently unknown. However, it is likely that the jets are governed by the same physics as those observed in other astrophysicsal objects.In this thesis, we study the jet in post-AGB binary systems. We collect high-resolution optical spectra of jet-creating post-AGB binary systems that were obtained from the HERMES spectrograph, mounted on the MERCATOR telescope. We develop a spatio-kinematic and radiative transfer model, from which we obtain important jet properties, such as opening angles, velocities, orientation and mass-loss rates. We show that our model is successfull in reproducing the jet feature in the spectra. We link the mass-loss rates in the jet with the mass-accretion rate in the accretion disk and the stellar and orbital properties of the system. Correlating the jet and accretion properties with the binary properties, provides us more insights on the binary interaction history of post-AGB binary systems and how they are connected to the formation of these jets.

Publication year:2021

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