Barium Clues: Unraveling the Origins of Carbon-Enhanced Ancient Stars
Sitnova et al. studied ten carbon-enhanced metal-poor stars to measure their barium isotope ratios. They found that CEMP-s stars have isotope patterns consistent with the slow neutron-capture (s-) process, while CEMP-rs stars show signatures matching the intermediate (i-) process. This distinction suggests that the i-process, rather than a mix of s- and r-processes, shaped the chemical makeup of many CEMP-rs stars.
Carbon-Enhanced Dwarf Stars: Clues from the Galactic Halo
This study analyzed over 1,000 dwarf carbon stars using SDSS and Gaia data, providing the first reliable distances for such a large sample. The results show that about 60% belong to the Milky Way’s halo and 30% to the thick disc, confirming they are mostly old, metal-poor stars. These findings establish dwarf carbon stars as valuable tracers of the Galaxy’s early history and stellar evolution.
Carbon Stars and Their Hidden Population: Insights from Gaia DR3
The study used Gaia DR3 data and machine learning to identify 43,574 carbon star candidates, including dwarf carbon (dC) stars, which inherit carbon from former AGB companions. They measured a dC space density of 1.96 × 10⁻⁶ stars per cubic parsec, showing they are more common than previously thought. This research improves understanding of binary star evolution and highlights the power of machine learning in astronomy. Future work will refine classifications and explore dC star variability.