All stars have atmospheres, but scientists have only truly observed such a veneer off our very own sun. But that’s all changed with a new image of the red supergiant Antares.
Sitting about 470 light-years away, Antares is about 12 times the mass of the sun and 700 times larger. Outside the sun, which scientists have already studied extensively, Antares is a perfect candidate for imaging a spectral map of the various material strewing around in its stellar atmosphere. The new findings, published in the journal Nature, illustrate the motion of the star’s excess material as it trudges through the late stages of its life en route to blowing up in a fiery supernova.
The new observations were captured by the European Southern Observatory’s Very Large Telescope, located in Chile at the Paranal Observatory. Its interferometer, which allows scientists to better measure surface material on Antares, produced the sharpest, clearest view of a star, besides the sun.
Bad news, though: Antares is shrinking. “How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century,” said Keiichi Ohnaka, a Chilean astronomer and lead author of the new Nature paper, in a statement. He calls the VLT and its interferometer “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.”
The new velocity map of Antares’ atmosphere shows the differences in speeds between the atmospheric gas of the star in different regions and the average speed of the entire star.
The findings are important, not simply because they demonstrate the power of new observational instruments, but also because they are the first step toward helping scientists better characterize and distinguish the more subtle details between different types of stars living out different phases of their lives. Our own sun, billions of years from now, will experience a similar sort of life that Antares currently has as it balloons into a red giant, which consumes much of the solar system.
But that’s a long time from now. Don’t fret about the existential dread of the star’s all-terrible future just yet. For now, take a look at the new picture of Antares and bask in the warm orange glow from afar.