# # Program information file # PROGRAM_ID 2024B078 PROGRAM_TITLE A Near-Infrared Spectroscopic Study of Mass Loss and Chemical Evolution in Core-Collapse Supernovae PROGRAM_INV1 Aravind Pazhayath Ravi PROGRAM_INV2 Samaporn Tinyanont PROGRAM_INV3 Jeonghee Rho PROGRAM_INV4 Ryan Foley PROGRAM_INV5 Seong Hyun Park PROGRAM_SCICAT extra-galactic PROGRAM_ABSTRACT_BEG Massive stars and their eventual fate as core-collapse supernovae [CCSNe] play a pivotal role in shaping the chemical and dynamic evolution of their respective host galaxies, though many aspects of their final phases of evolution, particularly at near-infrared [NIR] wavelengths, remain unknown. Our proposal aims to employ NIR spectroscopy of nearby CCSNe to address three key scientific inquiries: [1] How much He is left in the envelope of stripped-envelope [SE] SNe at core-collapse, and what mass-loss mechanism determines this residual amount? NIR spectroscopy provides a unique probe into the strong and uncontaminated He line at 2.058 microns that can be used to measure the residual 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 tell-tale sign of CSM interactions. [3] When and how does the important diagnostic molecule 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 microns and hot dust continuum, allowing us to measure its characteristics and test chemical evolution models of SN ejecta. Combining these observations with supplementary and concurrent optical observations will help answer the scientific questions we aim to address regarding the lives and deaths of massive stars. PROGRAM_ABSTRACT_END