R Aquarii is exploding
It is actually a pair of stars, a variable red giant and white dwarf star.
The two stars are orbiting each other and the white dwarf pulls material onto its surface from the red giant. This results in an explosion.
The giant red star varies in brightness by a factor of 750 times over a period of slightly more than one year. The stars orbital period is around 44 years.
R Aquarii is located around 700 light years from here in the constellation of Aquarius.
Given the constantly changing nature of the gases being expelled it provides an excellent opportunity to observe an unusual event.
The nebula region around the star may be the result of a nova type burst which may have been observed by Japanese astronomers in the year 930.
Imaged in Ha, OIII and RGB on my Planewave CDK 700 at Observatorio El Sauce, Chile.
Image acquisition and processing: Mike Selby