Researchers from the University of Sheffield and Imperial College London have observed a “retired” asymptotic giant branch (AGB) star passing through a young stellar region, something previously thought to be impossible.
The researchers identified that this interaction took place in one of the places where they thought that stars like our sun should form, using the Gaia satellite, a 740m € mission to map the positions of billions of stars in our galaxy.
The latest data release from Gaia, Data Release 3, means the research team can pinpoint the interloping stars. These interlopers are stars that did not form in the region, but are just passing through. The team previously found young interloping stars, but now found a much older, evolved star, known as an AGB, passing through a region.
Previous research has shown that these retired AGB stars produce large amounts of radioactively unstable chemical elements, Aluminum-26 and Iron-60. Aluminum-26 and Iron-60 were supplied to our young solar system during planet formation, and are thought to dominate Earth’s early internal heating.
Finally, Aluminum-26 and Iron-60 may indirectly contribute to our planet’s plate tectonics, which helps maintain a breathable atmosphere on Earth. The research team calculated how much Aluminum-26 and Iron-60 from the AGB a star like our sun can take up as it forms its planets.
Richard Parker, a lecturer in Astrophysics in the Department of Physics and Astronomy at the University of Sheffield, and the lead author of the study published in The Astrophysical Journal Letterssays, “Until now, researchers doubted that these old, evolved stars could meet young stars that form planets, so this discovery reveals more about the dynamics, relationships and journeys of stars.
“By showing that AGB stars can encounter young planetary systems, we show that other sources of Aluminum-26 and Iron-60, such as the wind and supernovae of more massive stars, may not necessarily explain the origin of these chemical elements in our solar system.”
Christina Schoettler, an Astrophysics research associate in the Department of Physics at Imperial College London, identified the AGB star in the Gaia DR3 data. He said, “Gaia changed our ideas about how stars form, and then move in the galaxy. This discovery of an old, evolved star near young planet-forming stars is a beautiful example of the power of serendipity in scientific research.”
The next step in this research is to look for other changing stars in young forming regions to determine how common these retired interlopers are.
More information:
Richard J. Parker et al, Isotopic Enrichment of Planetary Systems from Asymptotic Giant Branch Stars, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/ace24a
Provided by the University of Sheffield
Citation: Older evolved stars passing through a star-forming region could heat an early Earth (2023, July 24) retrieved 24 July 2023 from https://phys.org/news/2023-07-older-evolved-stars-star-forming-region.html
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