At a distance of 160,000 light-years from us, a star with a mass 2,000 times that of the Sun is dying. Today, this star has been photographed like never before – at very close range – and details of the star’s activity and the structure surrounding it have been revealed.
The recent image of the star was taken by the European Southern Observatory’s Very Large Telescope interferometer and shows the star unloading voluminous amounts of gas and dust as it dies. Observing how a star gets rid of these materials and how these materials remain around the star provides detailed information about the last stages of stellar life as well as the star system.
The WOH star G64 is a red supergiant (like the famous Betelgeuse) and is located in the Large Magellanic Cloud, a dwarf galaxy containing about 30 billion stars.
When the star spewed gas and dust into its neighborhood, this material formed a cocoon around the star, which can be seen in the image below as a thin elliptical ring. The VLTI data analysis was published today in the journal Astronomy & Astrophysics.
“This is the first time we’ve been able to take a magnified image of a dying star in a galaxy beyond our own,” said Keichi Onaka, an astrophysicist at the Universidad Andrés Bello in Chile and lead author of the study. “We found an egg-shaped cocoon in which the star is hidden, surrounded by a ring. This means that the dying star is ejecting a lot of material.”
The team decided to photograph WOH G64 for several reasons. First of all, the supergiant is ejecting matter at a frantic rate, which leads astrophysicists to the trace of the dynamics of a dying star that is destined to become a supernova, that is, to die in a bright explosion, ejecting matter into the universe. But the distance to WOH G64 is also precisely known, making it easier for the team to calculate the star’s mass and the energy it emits.
“This star is one of the most extreme of its kind, and any abrupt change could bring it closer to an explosive end,” said study co-author Jacco van Loon, director of the Kiel University Observatory, in an ESO press release.
“The existence of a dust torus enveloping the star has already been inferred from previous measurements, but this time the authors have managed to image it, so for the first time we can see it properly and model its shape and structure, which is an important step in our understanding of this supergiant star,” László Molnár, an astronomer at Hungary’s Konkoly Observatory, told Gizmodo in an email. Earlier this year, Molnár co-authored a new Betelgeuse study suggesting that the strange eclipse pattern of the star could be due to a smaller star orbiting the red supergiant.
“They also see changes in the data and the overall brightness of the star over time, which is very interesting in itself, but the conclusions are limited by the limited data available on this subject,” adds Molnar. “I hope that the upcoming 10-year Rubin Observatory study will address this issue as well.”
The team intends to take similar close-up images of the starry sky at longer wavelengths, which may reveal more material than the above photo. Namely, the ring-shaped deviation from the star shown in the illustration above may become visible in its images.
Until then, we’ll have to settle for this eerie, blurry “Eye of Sauron” of the red supergiant. But even with this resolution, it’s amazing that our telescopes can see such a distant star up close.
