The R Aquarii system is a symbiotic binary star surrounded by a large, dynamic nebula. Such binaries contain two stars in an unequal and complex relationship — a white dwarf and a red giant. In a disquieting act of stellar cannibalism, the white dwarf is stripping matter from its larger companion. The tormented red giant and the unstable white dwarf occasionally eject matter in weird spurts, loops, and trails — forming the curious shapes seen in these images.
In this unusual comparison image — a rare case of dynamic evolution captured with ground-based telescopes — we see the difference 15 years can make. It may be the mere blink of an eye on a cosmic timescale, but it provides us with a wonderful opportunity to observe a truly dynamic system as it changes shape in our skies.
These images show the evolution not only of R Aquarii, but also of our observational capabilities. The earlier view was captured by the Nordic Optical Telescope on the island of La Palma, Spain — a 2.5-meter (8.2-foot) telescope. The image from 2012, on the other hand, was captured by ESO’s 8-meter (26-foot) Very Large Telescope (VLT), and reveals far more intricate details of this fascinating symbiotic star.
This comparison image is the first installment in ESO’s R Aquarii Week, during which we will explore this intriguing object and its evolution. We will reveal the dramatic and ever-changing nature of R Aquarii, showing how it has evolved and expanded over years of observations.
This video shows the evolution of a chaotic and fascinating binary star system named R Aquarii. The time lapse begins with observations from the Nordic Optical Telescope taken in 1997. In the 15 years since that image was taken the system has been observed by many other telescopes, including ESO’s Very Large Telescope. This video lapses between a selection of these images, showing the expansion and evolution of the material surrounding R Aquarii.