English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

R Aqr is a symbiotic binary system consisting of a mira variable, a hotcompanion with a spectacular jet outflow, and an extended emission line nebula.We have used R Aqr as test target for the visual camera subsystem ZIMPOL, whichis part of the new extreme adaptive optics (AO) instrument SPHERE at the VeryLarge Telescope (VLT).  We compare our observations with data from the Hubble Space Telescope (HST)and illustrate the complementarity of the two instruments. We determine fromthe Halpha emission the position, size, geometric structure, and line fluxes ofthe jet source and the clouds in the innermost region (<2") of R Aqr anddetermine Halpha emissivities mean density, mass, recombination time scale, andother cloud parameters.  Our data resolve for the first time the R Aqr binary and we measure for thejet source a relative position 46+/-1 mas West of the mira. The central jetsource is the strongest Halpha component. North east and south west from thecentral source there are many clouds with very diverse structures. We see inthe SW a string of bright clouds arranged in a zig-zag pattern and, furtherout, more extended bubbles. In the N and NE we see a bright, very elongatedfilamentary structure and faint perpendicular "wisps" further out. Some jetclouds are also detected in the ZIMPOL [OI] and He I filters, as well as in theHST line filters for Halpha, [OIII], [NII], and [OI]. We determine jet cloudparameters and find a very well defined anti-correlation between cloud densityand distance to the central binary. Future Halpha observations will provide theorientation of the orbital plane of the binary and allow detailedhydrodynamical investigations of this jet outflow and its interaction with thewind of the red giant companion.

SPHERE / ZIMPOL observations of the symbiotic system R Aqr. I. Imaging of the stellar binary and the innermost jet clouds