Tracing Stellar Mergers with Chemistry: Carbon Isotopes Reveal Clues to Mysterious Stars
Astronomers studied massive α-enriched (MAE) stars, which look chemically old but appear too massive to be ancient. By measuring carbon isotope ratios (¹²C/¹³C), Zachary Maas and collaborators found most MAE stars resemble thick disk stars, while a few show evidence of mass transfer or mergers. The results suggest MAE stars form through multiple pathways, with carbon isotopes serving as key clues to their hidden histories.
Tracing the Chemical Fingerprints of Early Stars through Elemental Patterns in the Milky Way
This study examines the chemical evolution of elements like carbon, nitrogen, oxygen, and lithium in 52 metal-poor giant stars in the Milky Way’s halo to understand the early Galaxy’s chemical history. By analyzing patterns in “mixed” and “unmixed” stars, the researchers found that mixed stars show evidence of internal processes altering their elemental composition, while unmixed stars retain the chemical signature of the early Galaxy. Lithium detection in some stars supported this classification, and stellar rotation was identified as a crucial factor in explaining observed nitrogen levels.