Nav: Home

20 years keeping an eye on R Aquarii

June 07, 2018

In astronomical terms, at 600 light years away, the nebula around R Aquarii is rather close to us. The symbiotic star itself is made up of a red giant and a white dwarf which have interacted over centuries to form the magnificent surrounding nebula from material ejected from the system.

This system, known as R Aquarii for its apparent location in the large zodiacal constellation of Aquarius, is an important example of the effects of the gravitational interactions that occur between nearby stars. In the later stages of their evolution, when stars like the Sun grow to giant dimensions, lowering the surface gravity and allowing prodigious amount of matter to escape, the gravitation pull of a nearby star can become the dominant cause of their further evolution and destiny. As shown by R Aquarii, matter lost by one star can be sculpted into complex, albeit symmetric, nebulae, and in the process highly collimated outflows, called jets, can form. Jets are a common phenomenon in the Universe, and found around binary stars and black holes, as well as in the centre of the largest and most powerful galaxies.

R Aquarii is the closest-known stellar jet, allowing these complex physical processes to be studied in unprecedented detail. Given its proximity, it has been possible to follow the evolution of the nebula and its jet in real time by patiently obtaining sequence of images over many years. The study recently published in the journal Astronomy & Astrophysics (A&A) used telescopes at the Roque de los Muchachos Observatory (Garafía, La Palma) and Chile over the course of more than 20 years.

"While the large hourglass nebula expands in a regular way, the jet shows an extremely complex behaviour" says Tiina Liimets, the first author of the article and PhD student at the University of Tartu's Tartu Observatory (Estonia). The observations reveal the jets to be comprised of multiple knots of material, which at first glance don't seem to be flowing linearly away from the centre. "Instead they seem to be moving in apparently random directions, merging together and breaking apart, appearing and disappearing from view" states David Jones, researcher at the Instituto de Astrofísica de Canarias and co-author of the work. "This indicates that at the observed scales other external factors dominate the apparent evolution of the jet and its curvature, including the changes in the illumination from the central stars." adds Romano Corradi, Director of the Gran Telescopio the Canarias, and who obtained the first images for the study more than 25 years ago.

"We will continue to follow the evolution of R Aquarii over the coming decades, taking advantage of the next generation of telescopes and instruments, which will provide important information on this spectacular system and about the common processes that regulate the formation of all astrophysical jets" concludes Liimets.

The Observatories of the Instituto de Astrofísica de Canarias (IAC) form part of the Spanish network of Infraestructuras Científicas y Técnicas Singulares (ICTS).
-end-


Instituto de Astrofísica de Canarias (IAC)

Related Evolution Articles:

Chemical evolution -- One-pot wonder
Before life, there was RNA: Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich show how the four different letters of this genetic alphabet could be created from simple precursor molecules on early Earth -- under the same environmental conditions.
Catching evolution in the act
Researchers have produced some of the first evidence that shows that artificial selection and natural selection act on the same genes, a hypothesis predicted by Charles Darwin in 1859.
Guppies teach us why evolution happens
New study on guppies shows that animals evolve in response the the environment they create in the absence of predators, rather than in response to the risk of being eaten.
Undercover evolution
Our individuality is encrypted in our DNA, but it is deeper than expected.
Evolution designed by parasites
In 'Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation,' published in the September 2019 issue of The Quarterly Review of Biology, Marco Del Giudice explores an overlooked aspect of the relationship between parasites and their hosts by systematically discussing the ways in which parasitic behavior manipulation may encourage the evolution of mechanisms in the host's nervous and endocrine systems.
More Evolution News and Evolution Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...