Shocks and Photoionization of the Inner 650 AU Jet of the Interacting Binary Star R Aquarii from Multiwavelength Hubble Space Telescope Observations

• Published in: arXiv.org 2023-03
• Main Authors: Huang, Caroline D, Karovska, Margarita, Hack, Warren, Raymond, John C, Montez, Rodolfo, Kashyap, Vinay L
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Angular resolution; Binary stars; Depletion; Hubble Space Telescope; Kinematics; Photoionization; Resonance lines; Shock heating; Space telescopes; X ray binaries; X ray stars
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2303.00734

Astrophysical jets are present in a range of environments, including young stellar objects, X-ray binaries, and active galactic nuclei, but their formation is still not fully understood. As one of the nearest symbiotic binary stars, R Aquarii (\(D \sim 220\) pc) offers a unique opportunity to study the inner region within \(\sim\) 600 AU of the jet source, which is particularly crucial to our understanding of non-relativistic jet formation and origin. We present high-angular resolution ultraviolet and optical imaging from the \emph{Hubble} Space Telescope in six emission-line regions of the inner jet. Using these observations to obtain a range of representative line ratios for our system and kinematic data derived from a comparison with previous studies, we model the shocked gas in order to determine the relative roles of shock heating and photoionization in the R Aquarii system. We find that our shock models suggest a nonzero magnetic field is needed to describe the measured line ratios. We also find that the Mg~II\(\lambda\lambda\)2795,2802 intensities are overpredicted by our models for most of the jet regions, perhaps because of depletion onto grains or to opacity in these resonance lines.