by Astronomers have obtained the first detailed images of turbulent activity in a star other than our own Sun.
A time-lapse video released Wednesday (Sept. 11) shows huge bubbles of gas swirling around a nearby star called R Doradus, a red giant about 300 times larger than our sun which is located about 180 light-years away in the southern constellation Dorado. Like boiling soup on a stove, the star’s glowing material is bursting into bubbles on its surface, swelled to a whopping 75 times the size of our sun, according to astronomers.
“It’s spectacular that we can now directly image the details on the surface of stars so far away,” said Behzad Bojnodi Arbab, a doctoral student at Chalmers University of Technology in Sweden and co-author of a new study about the observations, published Wednesday in the journal Nature, said in a propositionThe latest images now allow astronomers to “observe physics that until now could mainly only be observed in our Sun,” Arbab added.
The video was compiled from the best images ever taken of the star’s chaotic surface, captured by a network of radio telescopes in Chile called the Atacama Large Millimeter/submillimeter Array, or ALMA In short, the images show the plasma bubbles, driven by heat rising from the star’s core, crashing down on the surface so violently that they appear to slightly deform the star.
Related: Meet ALMA: Stunning images from the giant radio telescope array
“We never expected the data to be of such high quality that we could see so many details of the convection on the surface of the star,” Wouter Vlemmings, the study’s lead researcher and a professor at Chalmers University of Technology, said in the statement.
Based on the latest snapshots of R Doradus, taken by ALMA from early July to August last year, Vlemmings and his colleagues estimate that the star’s plasma bubbles rise and fall in a monthly cycle, faster than the timeline followed by similar convective cells on the surface of our Sun.
“We don’t yet know the reason for the difference,” said Vlemmings.
Although R Doradus is incredibly bloated, its mass is comparable to that of our sun. So the study team suspects that the star reflects what our sun will look like in about five billion years, when it enters its red giant phase by blow up to the point where you ingest mercury and Venus.
“It seems that convection changes as a star ages, in ways we don’t yet understand,” Vlemmings said.
Previous ALMA observations showed that R Doradus is spinning at least two orders of magnitude faster than expected for a red giant. In the new study, Vlemmings and his team ruled out the possibility that the high spin is an illusion created by the star’s boiling surface, a hypothesis that recently brought forward by another team of astronomers who Betelgeuzeanother red giant in the constellation Orion that is known to be spinning 100 times faster than expected.
Vlemmings and his colleagues argue that the rotation rate of R Doradus is much longer than the one-month cycle of the planet’s convective bubbles, ruling out the possibility that telescopes would be fooled by such a coincidental alignment of gas bubbles.
