Signatures of r-process Enrichment in Supernovae from Collapsars

Abstract Despite recent progress, the astrophysical channels responsible for rapid neutron capture ( r -process) nucleosynthesis remain an unsettled question. Observations of kilonova following gravitational-wave-detected star merger GW170817 established mergers as one site -process, but additional sources may be needed to fully explain -process enrichment in universe. One intriguing possibility is that rapidly rotating massive stars undergoing core collapse launch -process-rich outflows off accretion disks formed from their infalling matter. In this scenario, winds are component supernova (SN) ejecta produced by “collapsar” explosions. We present first systematic study effects on emission collapsar-generated SNe. semianalytically model SN explosion out late times and determine its distinguishing features. The ease with which SNe can identified depends how effectively wind material mixes into initially -process-free outer layers ejecta. many cases, produces a near-infrared (NIR) excess detected within ∼75 days explosion. also discuss optimal targets observing strategies testing collapsar theory, find frequent monitoring optical NIR high-velocity few months after offers reasonable chance success while respecting finite resources. Such early identification candidates lays foundation nebular-phase spectroscopic follow-up mid-infrared, example, James Webb Space Telescope.