How a dying star is similar to a lava lamp

In a first, astronomers captured how convective forces power the quick bubbling movement of gas cells on the surface of a distant, massive star.

Sep 16, 2024 - 22:30

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How a dying star is similar to a lava lamp

Astronomers captured bubbling cells of gas Seventy five times as wide because the sun in this red giant big name

Three yellow circles packed with different patterns of light and dark

A time series of images of the massive name R Doradus shows bubbles of gas rising and sinking. The pictures were taken in 2023 with the ALMA telescope in Chile on July 18 (left), July 27 (center) and August 2 (right). The giant bubbles appear as bright and dark spots on the massive name’s surface and indicate convection within the massive name.

ALMA (ESO, NAOJ, NRAO), W. Vlemmings et al.

For the first time, astronomers have watched gas boil and bubble on the skin of a some distance off big name.

Scientists observed the red giant big name R Doradus with the Atacama Large Millimeter/submillimeter Array, or ALMA, in Chile over the course of four weeks in July and August 2023. The series of images shows large cells of gas rising to the massive name’s surface and sinking again, the team reports in Nature Eleventh of September.

Those bubbles are the hallmark of convection, the strategy that transports heat and energy across the insides of stars. “It’s kind of the principle of a lava lamp or boiling water,” says astronomer Wouter Vlemmings of the Chalmers University of Technology in Gothenburg, Sweden.

Similar bubbles have been seen on other giant stars. But that's the first time the bubbles’ speeds and motions have been tracked in a megastar with the exception of the sun.

Three yellow circles with smaller blue and red circles within them. — This diagram shows the sizes and locations of bubbles on the skin of R Doradus, as seen by ALMA over a period of some weeks. The red solid lines represent bubbles which can even be rising to the skin, and the blue dashed lines represent bubbles falling into the massive name towards its core.W. Vlemmings et al/Nature 2024This diagram shows the sizes and locations of bubbles on the skin of R Doradus, as seen by ALMA over a period of some weeks. The red solid lines represent bubbles which can even be rising to the skin, and the blue dashed lines represent bubbles falling into the massive name towards its core.W. Vlemmings et al/Nature 2024

R Doradus is about one hundred eighty light-years from Earth and is nearing the tip of its lifetime (SN: 7/23/21). As a component to its death process, it has puffed up to about 350 times the width of the sun, though both stars have about the identical mass.

The convective cells on the massive name’s surface are correspondingly enormous. A single cell spans Seventy five times the width of the sun. The cells upward push and fall all at some stage in the massive name at about 20 kilometers per second, about 60 times the speed of sound. That’s faster than astronomers expected in line with how convection works on the sun, and fast enough that a small fraction of the gas may maybe break out into space (SN: 12/5/13).

These observations and others find it irresistible truly is some distance ready to lend a hand illuminate the origins of the elements that make up stars, planets and folks (SN: eleven/29/20). Nearly the complete stardust that goes on to grow to be new objects “comes from stars equivalent to the one we looked at,” Vlemmings says. “But the approach to how this works remains to be no longer fully understood. We’d prefer to understand the physics, the small print of how this works.”