Astronomers captured the best ever image of a star’s surface and atmosphere.
Using ESO’s Very Large Telescope Interferometer astronomers have constructed the most detailed image ever of a star other than the Sun, the red supergiant star Antares.
Above image credit ESO/K. Ohnaka
They have also made the first map of the velocities of material in the atmosphere of a star other than the Sun, revealing unexpected turbulence in Antares’s huge extended atmosphere.
To the unaided eye the famous, bright star Antares shines with a strong red tint in the heart of the constellation of Scorpius (The Scorpion). It is a huge and comparatively cool red supergiant star in the late stages of its life, on the way to becoming a supernova.
A team of astronomers, led by Keiichi Ohnaka, of the Universidad Católica del Norte in Chile, has now used ESO’s Very Large Telescope Interferometer (VLTI) at the Paranal Observatory in Chile to map Antares’s surface and to measure the motions of the surface material. This is the best image of the surface and atmosphere of any star other than the Sun.
Artist’s impression of the red supergiant star Antares. Credit ESO/M. Kornmesser
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. This allows it to resolve fine details far beyond what can be seen with a single telescope alone.
Keiichi Ohnaka, who is also the lead author of the paper, said:
“How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century. 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.”