Left: A picture of the star WOH G64 taken with the Very Massive Telescope Interferometer in Chile. Proper: An artist’s impression of the star
ESO/Ok. Ohnaka et al., L. Calçada
Astronomers have taken the primary detailed image of a star in one other galaxy, greater than 160,000 gentle years away. The large star could also be exhibiting indicators that it’s simply years away from exploding, a course of now we have by no means seen intimately.
The biggest stars we all know of are purple supergiants, that are stars which have run out of hydrogen gasoline of their cores. A shell of hydrogen fuel surrounding the core burns as an alternative, massively increasing the quantity of the star.
One of many largest purple supergiants we all know of is WOH G64, generally known as the behemoth star. It’s between 1540 and 2575 instances the scale of the solar and resides in a satellite tv for pc galaxy of the Milky Manner, the Massive Magellanic Cloud. The star has been a goal for astronomers because it was found within the Seventies, however its distance has made it arduous to look at carefully.
Now, Jacco van Loon at Keele College, UK, and his colleagues have taken a close-up image of WOH G64 utilizing the Very Massive Telescope Interferometer within the Atacama desert in Chile, a group of 4 particular person telescopes linked collectively to operate as in the event that they had been a single 200-metre telescope. “In this image, we can see detail which would be equivalent to seeing an astronaut walking on the moon,” says van Loon. “You can’t see that through a normal telescope pointing at the moon.”
The picture, which was taken utilizing infrared gentle, exhibits a shiny ball of fuel and dirt, greater than 1000°C (1832°F), that the star has pumped out and that now surrounds it as a dense cocoon. “It’s really a structure we had not expected to actually see,” says van Loon. “We had expected just to see the star in the middle.”
The star seems dimmer than when it was final noticed, so the fuel and dirt in all probability appeared comparatively not too long ago, says van Loon. It might need been produced by the star blowing off its outer layers, which astronomers have by no means captured in a purple supergiant.
If that’s what occurred and the method resembles one seen in related stars known as blue supergiants, then it could be an indication that the star is many years or years away from exploding. “If we can see this star explode, we have much more detail about a star before it’s exploded than ever before,” says van Loon.
“It’s technically extremely impressive to be able to reconstruct an image of this object given its extreme distance,” says Paul Crowther on the College of Sheffield, UK.
Nevertheless, it’s tougher to say for sure whether or not the noticed fuel and dirt, and the related dimming in brightness, are an indication of an imminent explosion. “Stars like this object are well known to be highly variable,” says Crowther. “It’s simply what happens in these objects where they have this dense, slow outflow that doesn’t go very far from the star. They’re well known to be dust factories.”
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