First detailed image of the death of a star outside the Milky Way - 2,000 times larger than the Sun, 160,000 light-years away

Astronomers have for the first time captured an enlarged image of a star's death beyond the Milky Way. The Very Large Telescope Interferometer (VLTI) has "seen" the supergiant WOH G64.

WOH G64 is located an astonishing 160,000 light-years away in the Large Magellanic Cloud, a dwarf galaxy that is a satellite of the Milky Way. Astronomers have known about this star for some time, and it has earned the nickname "behemoth star" because it is an incredible 2,000 times larger than the Sun.

VLTI observed the star in such detail that it was able to detect a cocoon of gas and dust surrounding it. The eruption of material indicates that WOH G64 is dying and is in the final stages of its existence, ultimately leading to a powerful supernova explosion.

Astronomers have taken dozens of similar images of stars within the Milky Way, but until now, they have not been able to capture a star outside our galaxy with such detail. To obtain the actual image of WOH G64, researchers had to wait from the mid-2000s until the development of the second-generation VLTI telescope called GRAVITY, which combines light from four VLT telescopes to create high-sensitivity images of faint objects.

“We found that the star has undergone significant changes over the past 10 years, giving us a rare opportunity to observe its life in real-time,” says one of the researchers, Gerd Weigelt, a professor of astronomy at the Max Planck Institute.

As they approach the end of their lives, red supergiants shed their outer layers of gas and dust in a process that can last thousands of years. Keele Observatory director Jaco van Loon has been observing WOH G64 for the past three decades: “This star is one of the most extreme of its kind, and any sudden changes could bring it closer to an explosive end.”

WOH G64 dims due to the layers of stellar material it is shedding, creating an egg-shaped shell around it. The oddly shaped cocoon could also result from the gravitational influence of an undisclosed companion star nearby.

This is the first such image of WOH G64, but there may not be many more in the future. The behemoth star continues to expel gas and dust, making it dimmer and potentially complicating observations. Future instruments like GRAVITY+ may make it easier to obtain images.

The study was published on November 21 in the journal Astronomy & Astrophysics.

Source: Space.com