The first photo of a star in another galaxy was taken

Astronomers have taken the first detailed pictures of a star in another galaxy more than 160,000 light-years away. This giant star may be showing signs that it’s only a few years away from exploding, but we’ve never seen the process in detail.

The largest star we know of is a red supergiant, a star that has run out of hydrogen fuel in its core. Instead, the shell of hydrogen gas surrounding the core burns, causing the star’s volume to expand significantly.

One of the largest red supergiants that we know of is WOH G64, also known as a giant star. It is 1540 to 2575 times larger than the Sun and resides in the Large Magellanic Cloud, a satellite galaxy of the Milky Way. The star has attracted the attention of astronomers since its discovery in the 1970s, but its distance has made it difficult to study it in detail.

Now, Jaco van Loon of Keele University in the UK and his colleagues have used the Very Large Telescope Interferometer in Chile’s Atacama Desert to take close-up pictures of WOH G64. The interferometer functions as if four separate telescopes were linked together. It was a single 200 meter telescope. “In this image, you can see details similar to what you would see in an astronaut walking on the moon,” Van Loon said. “You can’t see it with a regular telescope aimed at the moon.”

The image, taken using infrared light, shows a bright ball of gas and dust, exhaled by the star and now surrounding it in a dense cocoon, heated to more than 1,000 degrees Celsius (1,832 degrees Fahrenheit). “This is a structure that we really didn’t expect to see,” Van Loon said. “We expected to have a star in the middle.”

The star appears dimmer than when it was last observed, so the gas and dust likely appeared relatively recently, Van Loon said. It may have been created by a star blowing away its outer layers, and astronomers have never seen it in a red supergiant.

If that happens, and the process is similar to that seen in similar stars called blue supergiants, it could be a sign that the star will take decades or even years to explode. I don’t know. “If we can see this star explode, we will be able to learn much more about the star before it explodes than ever before,” van Loon said.

“Being able to reconstruct images of this object from such a long distance is technically quite impressive,” said Paul Crowther from the University of Sheffield in the UK.

But it’s difficult to say with certainty whether the observed gases and dust, and the accompanying dimming of the brightness, are signs of an impending explosion. “Stars like this object are well known to be highly volatile,” Krauser said. “It’s simply what happens in these objects where there’s a dense, slow outflow that doesn’t go very far from the star. It’s well known that they are dust factories.”