spaceSpace and Physics

The Best Image Of A Distant Star Yet


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockJun 26 2017, 19:40 UTC

The image of Betelgeuse by ALMA. ESO/ALMA/P. Kervella

An international group of astronomers has snapped an incredible image of Betelgeuse, one of the best images of a star other than our Sun – certainly the best image at radio wavelengths. The incredible photo was possible thanks to the Atacama Large Millimeter/submillimeter Array.

Betelgeuse is a red supergiant star in the constellation of Orion, and one of the most luminous and largest stars in the sky. It is as big as 1,400 Suns while weighing only 11 times our star. It’s a star at the end of its life and astronomers believe it will go supernova in the immediate (cosmic) future. All these features, make Betelgeuse one of the most intriguing objects out there.


“Located about 650 light-years away, Betelgeuse is certainly not the closest star to our solar system, but its sheer size makes it an ideal target to image directly with ALMA,” Dr Pierre Kervella, an astronomer at the Paris Observatory and member of the team, said in a statement. “When we look at the night sky with our naked eyes, we see bright stars everywhere, but because they are so small, even the most powerful telescopes in the world struggle to image their surfaces. Our results show ALMA has the capability to image the surfaces of the largest stars in detail.”

The image of Betelgeuse by ALMA overlayed with the orbits of the planets in the solar system. ESO/ALMA/P. Kervella

The study, published in Astronomy & Astrophysics, provides some clues on the mechanism responsible for heating the very fluffy atmosphere of supergiant stars. The research unequivocally shows that the atmosphere is not heated uniformly, so the team suspects that magnetic large-scale convection (like a bubbling pot) is the cause of the asymmetry.

“ALMA now provides us with the capabilities to image surface features on nearby stars while also directly measuring the temperature of these features,” added lead author Dr Eamon O’Gorman, from the Dublin Institute for Advanced Studies. “We have known for decades that the visible surface of Betelgeuse is not uniform, but ALMA has now shown in beautiful detail that the temperature in its inner atmosphere is also not uniform. It looks like these temperature fluctuations could be caused by magnetic fields, similar to what we see on the Sun, our nearest star.”


Scientists hope that these observations will lead to a clearer picture of the late evolution of stars. We have many questions regarding supernovae evolution and how the elements we are all made of are produced. It might take millions of years for Betelgeuse to explode, but until then it might give us our clearest understanding of massive stars that we can get.

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