Study Finds 6 Red Dwarfs Engulfed Planets, Marked by Anomalous Lithium
Updated
Updated · Universe Today · May 28
Study Finds 6 Red Dwarfs Engulfed Planets, Marked by Anomalous Lithium
2 articles · Updated · Universe Today · May 28
Summary
Six early M-dwarf stars in three open clusters showed unexpected lithium levels, which researchers say are the clearest signs yet that some red dwarfs swallowed rocky planets early in their lives.
The team screened more than 114,000 stars in the Gaia-ESO survey and found the lithium-rich outliers among 50- to 200-million-year-old cluster stars, where lithium should already have been destroyed.
Models suggest engulfing about 3 to 10 Earth masses of rocky material could leave that chemical trace; the six stars were otherwise indistinguishable from sibling stars in position, motion and other properties.
The outliers account for roughly 2% to 3% of comparable stars, though the true engulfment rate could be higher if lithium signatures fade faster than expected.
Researchers said magnetic activity, rotation or unusual accretion histories could also explain the anomaly, but argued planetary engulfment is the most likely fit and may be common around planet-rich M-dwarfs.