# # Program information file # PROGRAM_ID 2024A073 PROGRAM_TITLE Probing Mass Loss and Chemical Evolution in Core-Collapse Supernovae with Near-Infrared Spectroscopy PROGRAM_INV1 Aravind Pazhayath Ravi PROGRAM_INV2 Samaporn Tinyanont PROGRAM_INV3 Ryan Foley PROGRAM_INV4 Jeonghee Rho PROGRAM_INV5 Charlie Kilpatrick PROGRAM_SCICAT extra-galactic PROGRAM_ABSTRACT_BEG Massive stars and their death in core-collapse supernovae [CCSNe] play significant roles in the chemical and dynamical evolution of their host galaxy. However, much remains unknown about how they live the last phase of their life and what determines the properties of the resulting CCSNe, especially at near-infrared [NIR] wavelengths. We propose to use NIR spectroscopy of nearby CCSNe to answer three scientific questions: [1] How much helium is left in the envelope of stripped-envelope [SE] SNe, and what mass-loss mechanism determines it? NIR spectroscopy probes strong and uncontaminated helium lines that can be used to measure He mass more robustly compared to the optical regime. [2] How much circumstellar medium [CSM] is there around red supergiants at the time of explosion, and does enhanced mass loss happen prior to the explosion? NIR spectroscopy of SNe IIP measures a high-velocity absorption of the He 1.083 micron line, which is a telltale sign of CSM interactions. [3] When and how does carbon monoxide [CO] and dust form in the ejecta of CCSNe, and how does its evolution compare to the theoretical predictions? Nebular phase NIR spectroscopy will detect CO first overtone emissions around 2.3 micron and hot dust continuum, allowing us to measure its mass to test chemical evolution models of SN ejecta. We will combine these observations with auxiliary optical data to answer the aforementioned scientific questions about the life and death of massive stars. PROGRAM_ABSTRACT_END