Have you ever paid any attention to the red giant Antares? At a glance, it’s nothing special: it’s the fifteenth-brightest star in the night sky, appears a little red when viewed with the naked eye, and sits in the constellation of Scorpius. It’s sometimes referred to as the “heart of the Scorpion”.
So far, so ordinary – except that, as revealed in a new Nature study, we’ve now got the best view of this star than any other in the universe with the sole exception of our own local pyre.
Rather wonderfully, apart from being a magnificent image, scientists have also discovered some rather strange currents swirling around on its surface, and at present, they have no idea what they are.
The red supergiant, which is roughly 12.4 times the mass of our Sun and about 883 times as wide, is about 550 light-years from Earth. A rather powerful optical telescope was required to see it, which was why it was imaged using the European Southern Observatory’s Very Large Telescope (VLT), in Chile.
Without a doubt, this is the world’s most cutting-edge visible-light astronomical observatory. Rather than just one device, the VLT is composed of four different telescopes. When the light detected by each is combined, it forms a far higher resolution picture than any individual telescope could ever hope for.
Pointing it at the Scorpion’s heart, a series of images were captured. It’s refreshing to see real images of a distant star rather than a pixelated mess or yet another artist’s impression alone, but why was Antares picked in the first place?
As the researchers from the Catholic University of the North in Chile and the Max Plank Institute for Radio Astronomy explain in their paper, this red supergiant is losing mass rapidly as it nears the end of its life, which will terminate in a spectacular supernova.
Although the triggers behind star death are relatively well known, the process of shedding solar mass isn’t, and this endeavor was partly designed to answer that query.
Instead, it’s actually brought up more questions. The star’s upper atmosphere is convecting, which is perfectly normal for a star – hotter masses rise, cool, then sink again or drift off into space. However, it appears that the surface of the star is actually too turbulent.
Colossal clumps of star stuff are moving at speeds of up to 20 kilometers (12.4 miles) per second, and the researchers simply don’t have a clue as to how.
“Convection alone cannot explain the observed turbulent motions and atmospheric extension, suggesting that an unidentified process is operating in the extended atmosphere,” the authors conclude in their study.
As ever, there are more things in heaven and Earth than are dreamt of in our philosophy.
1
