13 papers
Payne4GAIN: NLTE Corrections for Red Giants in Milky Way Mapper using H-Band Neural Network Emulators
Pierre Thibodeaux, Alexander P. Ji, Nicholas Storm +12
The majority of spectroscopic surveys assume local thermodynamic equilibrium (LTE) during the modeling of stellar spectra. This assumption begins to break down for luminous stars,…
The -Process Alliance: Actinide Abundances, Variation, and Evolution in Metal-Poor Stars
Shivani P. Shah, Rana Ezzeddine, Erika M. Holmbeck +11
The actinides, including thorium (Th), are the heaviest observable elements synthesized in the universe, holding clues to the extremes of the astrophysical and nuclear conditions o…
A nearly pristine star from the Large Magellanic Cloud
Alexander P. Ji, Vedant Chandra, Selenna Mejias-Torres +28
The first stars formed out of pristine gas, causing them to be so massive that none are expected to have survived until today. If their direct descendants were sufficiently low-mas…
Discovery of the First Five Carbon-Enhanced Metal-Poor Stars in the LMC
Madeline Lucey, Vedant Chandra, Alexander Ji +7
A substantial fraction of metal-poor stars in the local Milky Way halo exhibit large overabundances of carbon. These stars, dubbed Carbon-Enhanced Metal-Poor (CEMP) stars, provide…
A second-generation star in a relic dwarf galaxy
Anirudh Chiti, Vinicius M. Placco, Andrew B. Pace +22
Stars that contain only trace amounts of elements heavier than helium, referred to as having low "metallicity", preserve the chemical fingerprints of the first generation of stars…
Evaluating Classifications of Extremely Metal-poor Candidates Selected from Gaia XP Spectra
Riley Thai, Andrew R. Casey, Alexander Ji +2
Extremely metal-poor stars are intrinsically rare, but emerging methods exist to accurately classify them from all-sky Gaia XP low-resolution spectra. To assess their overall accur…