Astronomers Identified Star That Swallowed Planets
The star HD 129171 shows chemical signatures of consuming at least 11.2 Earth masses of rocky material.
Updated on Sept. 20, 2026 in Space
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Researchers have identified that the star HD 129171 consumed at least 11.2 Earth masses of rocky debris. This finding, published in Astronomy & Astrophysics, utilizes chemical anomalies to track planetary engulfment.
Why it matters
Identifying beryllium levels provides a longer-lasting chemical indicator of planetary consumption than previous methods using lithium. This discovery helps astronomers distinguish between chemical differences inherited at birth and those acquired through later orbital interactions.
The star HD 129171 is 30% richer in iron and contains 1.6 times more beryllium than its companion, HD 129209, despite both sharing an estimated age of 5 billion years.
The players
Very Large Telescope
A major ground-based observatory in Chile used for high-resolution spectroscopy.
Astronomy & Astrophysics
A peer-reviewed journal publishing research on theoretical and observational astronomy.
The details
Researchers utilized the UVES spectrograph—an instrument that measures the intensity of light at different wavelengths—on the Very Large Telescope in Chile to capture the chemical signatures of the star pair. By comparing the surface composition of these stars, which share a common birth history, the team modeled the quantity of rocky material required to shift the observed chemical ratios. Beryllium is particularly stable, allowing it to serve as a reliable marker for matter consumed long after a star's formation.
Timeline
In 2021, the initial study identified chemical differences in the star pair.
September 20, 2026, marks the public release of these findings.
The Tech Race
This research follows a pattern set by the UVES spectrograph stellar survey programs to identify chemical anomalies in binary star systems. It expands the search for planetary engulfment by establishing beryllium as a more durable tracer than traditional lithium-based models.
This study does not affect consumer technology or current workflows, as it is a fundamental astrophysical finding. It provides a new standard for researchers to analyze how stars evolve chemically over billions of years.
The takeaway
This discovery validates the use of beryllium as a reliable forensic tool for detecting historical planetary consumption in older stars. Future observations will track whether these chemical patterns appear in other binary systems to refine current models of star-planet interactions.
What happens next
The research team plans to initiate a broader survey of other mismatched stellar twins to determine if beryllium signatures can consistently identify past planetary engulfment events.
Further reading
Explore more findings regarding stellar composition and evolution in our Space section.
Source note: This article includes information reported by Earth.
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