Spectacular star system discovered which could explode to create powerful cosmic firework display

19th November 2018

A spectacular star system wrapped in an elegant spiral dust cloud has been discovered by astronomers.

The system is believed to contain a star that is spinning extremely fast, which could produce one of the most powerful explosions in the Universe. The binary star system, containing a pair of massive 'Wolf-Rayet' stars, has been discovered by an international team of researchers, including Professor Paul Crowther from the University of Sheffield, and published in Nature Astronomy. Wolf-Rayet stars are amongst the hottest stars in the Universe, blast out powerful winds of hot gas, and represent the last stage in the evolution of the most massive stars prior to exploding as a supernova. Located around 8,000 light years away half a billion times further away than our Sun the binary system is surrounded by a gigantic dust cloud. The collision between the winds of the two stars can form dust, which takes on elegant spiral pinwheel shapes as the stars orbit each other. Using the Very Large Telescope (VLT) in Chile and the Anglo-Australian Telescope (AAT) in Australia, the team has found that the star system is producing incredibly fast winds, 100,000 times quicker than a hurricane on Earth. This wind speed is routine for Wolf-Rayet stars. However, the researchers discovered that the dust cloud is moving much slower. The differing speeds of wind and dust suggest that the Wolf-Rayet stars are spewing out faster gas at the poles and slower gas at the equator, according to the study, which was led by Dr Joseph Callingham from the Netherlands Institute for Radio Astronomy. Co-author Dr Benjamin Pope from New York University commented: -One way for such different winds to happen is via critical rotation. Critical rotation is needed in most supernova models for a star's fiery death to be accompanied by the most energetic explosion in the Universe: a gamma-ray burst. Professor Paul Crowther from the University of Sheffield's Department of Physics and Astronomy, said: -It remains a mystery how dust - similar to soot from a candle - forms in such harsh environments, but this newly discovered system is the most beautiful case seen to date. The study was conducted by Dr Joseph Callingham from the Netherlands Institute for Radio Astronomy (ASTRON), Professor Peter Tuthill from the University of Sydney, Dr Benjamin Pope, NASA Sagan Fellow at New York University, Dr P. Williams from the University of Edinburgh, Professor Paul Crowther from the University of Sheffield, Mr. M. Edwards from the University of Sydney, Dr B. Norris from the University of Sydney and Dr L. Kedziora-Chudczer from the University of New South Wales. To access the paper after the embargo has lifted, visit: http://dx.doi.org/10.1038/s41550-018-0617-7 Scientists at the University of Sheffield's Department of Physics and Astronomy are conducting research to explore the fundamental laws of the Universe and developing pioneering technologies with real-world applications. Sheffield researchers are looking beyond our planet to map out distant galaxies, tackling global challenges, such as energy security, and exploring opportunities presented by quantum computing and 2D materials. Scientists at the University play a crucial role in major international collaborations, from the ATLAS project at CERN's Large Hadron Collider and the LIGO collaboration behind the detection of gravitational waves, to neutrino detection as part of the T2K Collaboration in Japan and dark matter experiments with the LUK-Zeplin experiment at the Sanford Underground Research Facility. Sheffield astrophysicists work closely with the teams behind NASA's Hubble Space Telescope and the Isaac Newton Group of Telescopes on La Palma in the Canary Islands, while biological physicists at the University are leading the Imagine: Imaging Life project a major University of Sheffield research initiative that is applying revolutionary microscopy techniques to biology and medicine. The University is also training the next generation of physicists through a range of three and four year undergraduate degrees in physics and astrophysics.