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swedish researchers recently published a paper in the british journal nature, saying that when they observed the star r doradus 178 light years away, they saw a huge bubble float to the surface, sink after cooling and return to the interior of the star. this is the first time that humans have observed the convection structure and its movement on a star outside the solar system in detail, which will help us to deeply understand the evolution of stars.

r doradus is located in the southern sky. it is a red giant star with a diameter of about 350 times that of the sun and a mass similar to that of the sun. about 5 billion years from now, when the sun enters its old age, it may look like r doradus now.

from july to august 2023, researchers from the chalmers institute of technology in sweden used the atacama large millimeter/submillimeter array telescope in chile to observe r doradus and took multiple images. from these images, we can see a huge bubble 75 times larger in diameter than the sun rising and sinking, with a movement period of about one month, which is faster than previous theoretical predictions.

nuclear fusion reactions inside stars continuously release heat, hot gases rise and cool gases sink, forming convection, transferring heat and bringing heavy elements such as carbon and nitrogen generated in the core to the surface. stars eject matter and lose mass through stellar winds, and convection is also believed to be the cause of stellar winds. the research team plans to further observe r doradus to study whether the bubbles it emits give rise to stellar winds.

previously, people have observed the convection of the sun in detail, but the research on other stars is still based on theoretical models and lacks actual observations. the researchers said they do not understand why the convection of r doradus is faster than that calculated based on the sun. it is possible that the convection pattern of the star has changed after aging.