For the first time, astronomers have used some of Earth’s most powerful telescopes to create the clearest ever image of a star’s surface and atmosphere.
In a major breakthrough for our understanding of the wider universe, a team of astronomers has generated the clearest ever image of another star.
Located more than 600 light years from Earth, Antares is a red supergiant with 12 times the mass of our sun and a diameter about 700 times as much. During its lifetime, it has shed three solar masses of material.
Using the European Southern Observatory’s Very Large Telescope Interferometer (VLTI) in Chile, Keiichi Ohnaka and his team were able to map Antares’ surface and measure the motions of the surface material.
Thanks to the VLTI’s unique ability to combine the light from up to four telescopes, the team was able to create a virtual telescope equivalent to a single mirror, up to 200 metres, giving it a view unlike any other.
It wasn’t so straightforward though, as another instrument called AMBER was used to make separate images of the surface of Antares over a small range of infrared wavelengths.
‘An entirely new window to observe stars’
It was then a matter of using this data to calculate the difference between the speed of the atmospheric gas at various positions on the star, and the average speed over the entire star.
This generated a map of the relative speed of the atmospheric gas across the entire disc of Antares, thereby becoming the first ever one created for a star other than the sun.
“How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century,” Ohnaka said.
“The VLTI is the only facility that can directly measure the gas motions in the extended atmosphere of Antares – a crucial step towards clarifying this problem. The next challenge is to identify what’s driving the turbulent motions.”
Following this breakthrough, Ohnaka said that this observing technique can be applied to different types of stars to study their surfaces and atmospheres in unprecedented detail, opening “an entirely new window to observe stars”.