Research: Super telescope reveals galactic battle

2020-02-21

A long time ago in a remote part of the galaxy, two stars met in a fight for survival. Now the light of that confrontation is reaching our planet, just in time for astronomers to document the sequence of events in images using new technology.

With the ALMA super telescope, astronomers have succeeded in depicting the clash between one of the smaller stars in the Milky Way and a red giant.
Photograph: ALMA (ESO/NAOJ/NRAO), Olofsson et al. Acknowledgement: Robert Cumming

With the ALMA super telescope, astronomers have been able to depict the clash between one of the smaller stars in the Milky Way and a red giant – a star whose hydrogen has been consumed and that is growing far beyond its original size as it dies. During the confrontation that took place about 700 years ago, the smaller star moves in a spiral path towards the larger star’s nucleus, causing it to eject gas layers, exposing its core.

“For four decades we have captured energy signals indicating that something is going on in the area, which we estimate to be about 3,000 light years away. Using new technology, we can finally document the process in images, and the material we now have access to is of very high quality,” says Sofia Ramstedt, a researcher at the Department of Physics and Astronomy.

The meeting between the two stars is a lengthy process. Though researchers have already been following several similar events in space, images of this type of confrontation have never been captured before. The result adds a very important component to our knowledge of what happens when a star perishes.

Creating a 3D map of the Milky Way

“We know that during the death process, stars shed their outer layers, leaving behind a small, very dense white dwarf. However, we cannot answer why or exactly how this happens. The images we now are getting show a transition phase accelerated by the confrontation and which is in a gap between previously studied stages. On the whole, this provides important information about what fate awaits our own sun as well as the universe as a whole,” says Ramstedt.

The ALMA telescope, an international resource located in Chile’s Atacama region, has been operating since 2013. As a member state of the European Southern Observatory (ESO), Swedish astronomers can apply for research time at the facility.

“I am also working on a project in which we use images from ALMA to map all the sun-like stars in the southern sky within 1,500 to 2,000 light years from Earth. We hope to identify interesting objects for further research. We also look forward to the results of the Gaia satellite’s mission to create a three-dimensional map of the Milky Way and the launch of the James Webb telescope, which is expected to take place in March 2021. A great many extremely exciting things are happening in astronomy right now,” Sofia Ramstedt notes.

Magnus Alsne

Facts

  • The depicted confrontation took place in the HD 101584 Star System.
  • HD 101584 is included in the Centaurus constellation in the southern sky.
  • ALMA (Atacama Large Millimeter/submillimeter Array) is a collaboration between ESO, the National Science Foundation, the National Institutes of Natural Sciences and Chile.