Shaping the nebula around the symbiotic system R Aquarii

TL;DR

This study models the complex nebula around R Aquarii using spectroscopic data and shape software, revealing three main structures with different ages and suggesting jet interactions shape the nebula.

Contribution

It provides a detailed morpho-kinematic model of R Aquarii's nebula, highlighting the interaction of jets with circumstellar material and estimating the ages of nebular components.

Findings

Identified three main nebular structures with distinct ages.

Proposed the spiral filament traces jet interactions.

Estimated the jet activity ceased about 230 years ago.

Abstract

We present an analysis of high-dispersion spectroscopic observations of the symbiotic system R Aquarii (R Aqr) obtained with the Manchester Echelle Spectrograph (MES) at the 2.1 m telescope of the San Pedro M\'artir Observatory (Mexico). An interpretation of these data is presented by means of the shape software to disclose the morpho-kinematics of the nebulosities associated with R Aqr. The best model that reproduces narrow-band images and position-velocity diagrams is composed by three structures: an outer (large) hourglass structure surrounding an inner bipolar with a spiral-like filament entwined around the later. Different expansion velocity patterns are predefined for each structure, which predict kinematic ages of $\tau_{1}$=450$\pm$25 yr (outer hourglass), $\tau_{2}$=240$\pm$20 yr (inner bipolar) and $\tau_{3}$=215$\pm$20 yr (spiral-like filament). We suggest that the spiral-like filament is tracing the regions of interaction of the precessing jet with the circumstellar material, which simultaneously carves the inner bipolar structure. If a similar process created the large hourglass structure, it means that the action of the jet ceased for about 230 yr. We discuss the implication for other unresolved symbiotic systems detected in X-rays.