Astronomers snap first up-close image of a star outside our galaxy

It’s sometimes hard to grasp the scale of our universe, when even our own galaxy is so large and filled with billions of stars. But all of the stars that we have seen in detail are contained within the roughly 100,000 light-year span of our Milky Way galaxy. That is, until now, as astronomers recently observed a star outside of our galaxy up close for the first time.

The researchers looked at star WOH G64, located 160,000 light-years away, using the European Southern Observatory’s Very Large Telescope Interferometer. The image shows the main bulk of the star surrounded by a puffy cocoon of dust and gas.

This is an image of the star WOH G64, taken by the GRAVITY instrument on the European Southern Observatory’s Very Large Telescope Interferometer. This is the first close-up picture of a star outside our own galaxy, the Milky Way. ESO/K. Ohnaka et al.

“We discovered an egg-shaped cocoon closely surrounding the star,” said lead researcher Keiichi Ohnaka of the Universidad Andrés Bello in Chile in a statement. “We are excited because this may be related to the drastic ejection of material from the dying star before a supernova explosion.”

The star is located in one of the satellite galaxies of the Milky Way, called the Large Magellanic Cloud. This satellite galaxy orbits around the Milky Way and is much smaller, at around one-hundredth of the mass of our galaxy. The star itself is a big one, though, coming in at 2,000 times the size of our sun — making it a type called a red supergiant.

The Large Magellanic Cloud is a satellite galaxy to the Milky Way, located 160 000 light-years away from us. Despite the staggering distance, the GRAVITY instrument of the European Southern Observatory’s Very Large Telescope Interferometer (ESO’s VLTI), managed to take a close-up picture of the giant star WOH G64. This image shows the location of the star within the Large Magellanic Cloud, with some of the VLTI’s Auxiliary Telescopes in the foreground. ESO/K. Ohnaka et al./Y. Beletsky (LCO)

This huge star is undergoing a process of change, in which it is shedding off its outer layers and throwing off dust and gas, creating the cocoon. This material could be what is causing the star to dim, and the fast rate of change suggests it could be set to go supernova soon.

“We have found that the star has been experiencing a significant change in the last 10 years, providing us with a rare opportunity to witness a star’s life in real time,” said fellow researcher Gerd Weigelt of the Max Planck Institute for Radio Astronomy in Germany.

Jacco van Loon of Keele University agreed: “This star is one of the most extreme of its kind, and any drastic change may bring it closer to an explosive end.”