. | . |
20 years keeping an eye on R Aquarii by Staff Writers La Laguna, Spain (SPX) Jun 08, 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 and Astrophysics (A and A) used telescopes at the Roque de los Muchachos Observatory (Garafia, 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 Astrofisica 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 Astrofisica de Canarias (IAC) form part of the Spanish network of Infraestructuras Cientificas y Tecnicas Singulares (ICTS).
Collisions Spray Heavy Elements Throughout Small Galaxies Pasadena CA (SPX) Jun 08, 2018 Caltech scientists have found, for the first time, that merging pairs of neutron stars - the burnt-out cores of stars that have exploded - create the majority of heavy elements in small "dwarf" galaxies. Heavy elements, such as silver and gold, are key for planet formation and even life itself. By studying these dwarf galaxies, the researchers hope to learn more about the primary sources of heavy elements for the whole universe. The origin of the majority of the heaviest elements of the periodic ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |