Stars, similar to our Sun, will eventually die by expanding outwards an becoming red giants. When our Sun dies – in about 7.5 billion years – it will grow so large that it will engulfs Mercury, Venus and Earth.
That sounds terrifying, but the explosion and expansion will produce the most beautiful nebula. There’s has been some speculation about would happen to our Sun in the far-off future.
Some scientists believe that our Sun will swell into a red giant, then collapse into a relatively cool white dwarf; a “very dim reminder that our solar system once existed.”
However, others believe that our Sun will go out in style and create a planetary nebula – “the prettiest objects in the sky” – which will be visible from millions of light-years away.
A stellar fight
A similar display has recently been observed by the ESO (European Southern Observatory), using the Atacama Large Millimeter/submillimeter Array (ALMA).
ALMA, an astronomical interferometer of 66 radio telescopes in the Atacama Desert of northern Chile, spotted a peculiar gas cloud that resulted from a confrontation between two stars.
One star grew so large it engulfed the other. The other star, in turn, spiralled towards its partner; provoking it into shedding its outer layers in a cosmic array of colours.
This new ALMA image shows the outcome of a stellar fight: a complex and stunning gas environment surrounding the binary HD101584. The colours represent speed, going from blue — gas moving the fastest towards us — to red — gas moving the fastest away from us. Photo: ALMA (ESO/NAOJ/NRAO), Olofsson et al. Acknowledgement: Robert Cumming
According to the ESO, the dying sun will lose its outer layers and leave behind a hot, dense white dwarf. Hans Olofsson of the Chalmers University of Technology, Sweden, explains:
“The star system HD101584 is special in the sense that this ‘death process’’was terminated prematurely and dramatically as a nearby low-mass companion star was engulfed by the giant”.
Thanks to new observations with ALMA, Olofsson and his research team describes what happened in the double-star system HD101584 as a stellar fight.
Understanding the evolution of a star
The team says the complex structure of the gas in the HD101584 nebula is “due to the smaller star’s spiralling towards the red giant, as well as to the jets of gas that formed in this process”.
As a deadly blow to the already defeated gas layers, these jets blasted through the previously ejected material. It then formed the rings of gas and the bright bluish and reddish blobs seen in the nebula.
A silver lining of a stellar fight is that it helps astronomers to better understand the final evolution of stars like the Sun. Co-author Sofia Ramstedt from Uppsala University, Sweden, adds:
“Currently, we can describe the death processes common to many Sun-like stars; we cannot explain why or exactly how they happen. HD101584 gives us important clues to solve this puzzle; it is currently in a short transitional phase between better studied evolutionary stages.
Ramstedt adds that the team will continue their research using the Extremely Large Telescope (ETO); which is currently under construction in Chile’s Atacama Desert.
“It will provide information on the ‘heart’ of the object’,” Olofsson concludes.
The world’s biggest eye on the sky. An artist’s depiction of the Extremely Large Telescope (ELT) on Cerro Armazones in northern Chile. At a ceremony in Garching bei München, Germany on 25 May 2016, ESO signed the contract with the ACe Consortium, consisting of Astaldi, Cimolai and the nominated sub-contractor EIE Group for the dome and telescope structure of the ELT. This was the largest contract ever awarded by ESO and the largest ever contract in ground-based astronomy. At this occasion the construction design of the E-ELT was unveiled. This artist’s rendering of the ELT is based on the detailed construction design for the telescope. Image: ESO.org