You've probably seen close-up images of our Sun, and even videos of the material moving around on our system's star. We've had these images for a long time, which isn't surprising. The Sun is pretty close to us, relatively speaking, and it's the largest body in the solar system. We've had the technology capable of looking at it (safely, of course) for many years.
Other stars, however, pose the problem of just being too far away to image very well. Some of them are many times the size of the Sun, but because of their distance, even with the best of telescopes, they show up as blurs of light. We can tell their size and temperatures due to their colors, distances, magnitudes of light, and how other objects interact with them, but not very much else.
Recently, however, scientists have used the Very Large Telescope Interferometer (VLTI) at the European Southern Observatory to construct the most detailed image ever of a star other than our Sun. They also were able to make a map of the velocities of materials in the star's atmosphere, something, again, they were unable to do before with any star but our Sun.
Antares is a red supergiant star in the constellation Scorpius. It shines with a red glow from near the center of the constellation, and it's in the later stages of its life. Some day, probably long after you and I are dead, it will become a supernova. Astronomers at the VLTI at the Paranal Observatory in Chile are able to combine the light from up to four telescopes at the facility to make a virtual telescope that has the equivalent of a mirror 200 meters across. That's...really big. They can use this mega-Voltron telescope to see things at a much higher resolution than what can be seen with a single telescope. And that's how they were able to "see" this:
Sure, it looks blurry and smeary, but remember, Antares is 550 light years away! It's a supergiant with a diameter about 700 times larger than our Sun, but seeing detail on something that far away is a huge step forward for astronomers, especially since Antares is a red supergiant with a mystery.
Stars begin life as normal, ordinary stars, like our Sun. When stars get older, if they have the right amount of mass, they become red giant stars. This means that they balloon out, cool off, and change color. Stars like our sun will balloon out, then after another period of time, will burn off enough energy to shrink again into a white dwarf, and then continue to cool until...well...poof. But a star with a huge amount of mass will become a red SUPERgiant, like Antares, which will eventually explode and become a supernova. Right now, Antares has a mass of about twelve Suns. But when it was formed, it's thought to have had a mass of fifteen Suns. Where did all that mass go?
"How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century," says lead astronomer on the project, Keiichi Ohnaka. "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 real challenge is to identify what's driving the turbulent motions."
Because of the VLTI's awesome observing powers, scientists were not only able to get a good photo of the star. They were able to map the movement of the material that make the star up.
Yep, this is the map. In order to read this map properly, you need to think in three dimensions. The red blobs are materials that are moving away from us, and the blue blobs are moving toward us. All the colors in between are moving in directions between (so green would be sort of coming toward, but at some angle, etc). The black ring is where measurements were not possible.
This is the first time these measurements were possible on a star other than the Sun. And scientists made a discovery: because they saw low density gases moving much further from the star than they had first predicted, in an extended atmosphere. Because of this movement, they have concluded this gas is not the result of convection, the way material usually moves around in stars, transferring from the core to the outer atmosphere. They can't explain it yet, but are exploring the possibility that a new, unknown process might be behind the movement of the gasses of the outer atmospheres of red supergiants.
"In the future, this observing technique can be applied to different types of stars to study their surfaces and atmospheres in unprecedented detail. This has been limited to just the Sun up to now," says Ohnaka. "Our work brings stellar astrophysics to a new dimension and opens an entirely new window to observe stars."
Melanie R. Meadors is an author of fantasy where heroes don't always carry swords and knights in shining armor often lose to nerds who study their weaknesses. She has edited two upcoming genre anthologies, MECH: Age of Steel and HATH NO FURY, and is the science and pop culture blogger at The Once and Future Podcast. You can find her at her website, melaniermeadors.com, on Facebook, and Twitter, @melaniermeadors.