James Webb Space Telescope Feed Post

JWST NIRSpec+MIRI Observations of the nearby Type IIP supernova 2022acko

NIRCAM F300M, F355M, F360M 30 pixel × 30 pixel stamps of SN 2022acko, and MIRI F770W, F1000W and F1130W 30 pixel × 30 pixel stamps of SN 2022acko. We do not show the F2100W filter as the SN is not visible. Abstract: We present JWST spectral and photometric observations of the Type IIP supernova (SN) 2022acko at ~50 days past explosion. These data are the first JWST spectral observations of a core-collapse SN. We identify ~30 different H I features, other features associated with products produced from the CNO cycle, and s-process elements such as Sc II and Ba II. By combining the JWST spectra with ground-based optical and NIR spectra, we construct a full Spectral Energy Distribution from 0.4 to 25 microns and find that the JWST spectra are fully consistent with the simultaneous JWST photometry. The data lack signatures of CO formation and we estimate a limit on the CO mass of < 10^{-8} solar mass. We demonstrate how the CO fundamental band limits can be used to probe underlying physics during stellar evolution, explosion, and the environment. The observations indicate little mixing between the H envelope and C/O core in the ejecta and show no evidence of dust. The data presented here set a critical baseline for future JWST observations, where possible molecular and dust formation may be seen.