Temporal Variations and Spectroscopy of the Core of R Aquarii
Session 84 -- Variable Stars
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [84.10] Temporal Variations and Spectroscopy of the Core of R Aquarii

Warren J. Hack, Francesco Paresce (Space Telescope Science Institute)

The inner region of the symbiotic system R Aquarii was imaged with the Faint Object Camera on the Hubble Space Telescope (HST) in order to determine the source and structure of the highly collimated bipolar jet near the central Mira variable. We present images which cover both a wide wavelength and temporal range taken through narrow and medium band filters F501N, F253M and F190M containing the [O{\small III}]~$\lambda$5007, [O{\small II}]~$\lambda$2470, C{\small III}]~$\lambda$1909 emission lines taken approximately a pulsation period apart on October~1991 and December~1992 with a single image taken just after minimum in October~1993. The jet can be clearly detected in the UV down to at least 15~AU of the Mira, placing its source well within the expected binary orbit. Those features within 100~AU in the NE jet vary in phase with the Mira while those outside this region change the positions of emission supporting the idea that the Mira wind influences the speed or direction of the jet. In addition to the direct images, objective prism images taken in October~1991 and December~1992 allow us to track which lines are responsible for the majority of the emission in each of the features from one epoch to the next. The line ratios derived from the images and spectra are consistent with a shock being driven through material left over from an earlier episode of mass ejection.