R Aquarii's Binary Stars Reveal Explosive Secrets at Closest Approach

A team of astronomers at the University of Tartu's Tartu Observatory has uncovered new details about the binary star system R Aquarii. Their research reveals that powerful jets of matter erupt precisely when the two stars draw closest together, creating a white screen of activity. The findings, now published in Astronomy & Astrophysics, confirm a long-standing hypothesis about how these jets form.

R Aquarii is a symbiotic system made up of a red giant and a white star at very different stages of their evolution. The red giant sheds stellar wind, while the white star follows an elongated 40-year orbit around it. When the two stars reach their nearest point—known as periastron—they drive mass transfer, creating an unstable accretion disk around the white star.

Using the Gemini South Telescope in Chile and advanced speckle imaging, the team captured high-resolution observations of the system. Their data showed that matter is expelled in narrow, cone-shaped jets, shooting out perpendicular to the disk like water from a faucet. These jets appear on both sides of the disk only during the stars' closest encounters, illuminating the system in a white light show.

Tiina Liimets, an astronomer at Tartu Observatory, highlighted the importance of approaching scientific work with an open mind. The discovery not only matches earlier predictions but also provides concrete evidence linking periastron events to jet formation in binary star systems.

The study offers clear confirmation of a decades-old theory about jet production in R Aquarii. By observing the precise timing of these eruptions, researchers have deepened their understanding of how mass transfer and orbital dynamics shape stellar phenomena. The findings were made possible through high-resolution imaging and international collaboration.