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NASA's planet-hunting TESS Mission keeps giving astronomers new realities to examine and explain.
Case in point: astronomers using the tools of asteroseismology—the observations and measurements of a star's oscillations, or starquakes, that appear as changes in brightness—have learned more about two stars bright enough to be visible in a dark sky to the naked eye. These red-giant stars—older, "retired" stars no longer burning hydrogen in their cores—are known as HD 212771 and HD 203949.
Stars - Planets - TESS - Data - Exoplanets
Both stars are known to host their own planets. And the TESS data indicate one of those "exoplanets" (the general term for planets that orbit stars other than our sun) is so close to its host star it shouldn't have survived the star's expansion as a red giant—if, that is, the star is old enough to have expanded and retreated.
Steve Kawaler, an Iowa State University distinguished professor of physics and astronomy, and Miles Lucas, a recent Iowa State graduate and current doctoral student at the University of Hawaii at Manoa, are part of the TESS asteroseismology study team.
Notes - Stars - Kawaler - Data - Values—mass
"We listened to the notes the stars were singing," Kawaler said. "We used that data to determine actual values—mass, radius and evolutionary stage—for these stars. Asteroseismology can tell us all these things—and more—about stars that are difficult to obtain with other tools."
The team of 48 astronomers describe their findings in a paper recently published by The Astrophysical Journal. The lead author is Tiago L. Campante of Portugal's Universidade do Porto.
Paper - Use - TESS - Data - Oscillations
The paper describes the first use of TESS data to detect oscillations of stars already known to host exoplanets. The new work, the authors wrote, is a way of "further showcasing the mission's potential to conduct asteroseismology of red-giant stars."
Kawaler said the study indicated star HD 203949...
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A pox on both their houses!