Astronomers capture best image yet of a star other than the sun

Geronimo Vena
Agosto 27, 2017

Famously known as red supergiant star Antares, was mapped with the aid of Very Large Telescope Interferometer [VLTI] in Chile. The subject of the photo is the supergiant Antares, visible to the unaided eye in the constellation Scorpius. Compared to our Sun, its mass is 12 times greater and its diameter is 700 times more, these characteristics turn Antares into the biggest and brightest star that exists in our galaxy.

A supermassive alien star called Antares has been analysed with the help of three telescopes by a team of astronomers from Universidad Católica del Norte in Chile. Astronomers of the same performed the best ever image of the star outside our solar system. This capability allows the VLTI to spot the finer details the telescopes won't be able to see on their own.

The VLTI is a unique facility that can combine the light from up to four telescopes, either the 8.2-metre Unit Telescopes, or the smaller Auxiliary Telescopes, to create a virtual telescope equivalent to a single mirror up to 200 metres across.

"How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century", said Keiichi Ohnaka, who is also the lead author of the paper. "The next challenge is to identify what's driving the turbulent motions", Ohnaka added.

Image by ESO  M. Kornmesser
Image by ESO M. Kornmesser

Using ESO's Very Large Telescope Interferometer astronomers have constructed this remarkable image of the red supergiant star Antares. The data they gathered was used to calculate the difference between the speed of the atmospheric gas various points on the star and the average speed across the whole star. The astronomers created a map for another star apart from our Sun, that portrays the relative speed of the atmospheric gas throughout the Antares disc. Armed with the new results, the team created a 2D velocity map of a star's atmosphere using the VLTI. This also confirmed that there are clumps of gas in the atmosphere of Antares nearly 2 times its radii. They reason that a new, now unknown, process may be needed to explain these movements in the extended atmospheres of red supergiants like Antares.

"In the future, this observing technique can be applied to different types of stars to study their surfaces and atmospheres in unprecedented detail", says Ohnaka.

"Our work brings stellar astrophysics to a new dimension and opens an entirely new window to observe stars", Ohnaka concluded.

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