Abstract

Contributed Talk - Splinter StellarEndpoints   (MW-2235)

Multiwavelength Signatures of Supernova Shock Breakout

Wun-Yi Chen, Ke-Jung Chen, Keiichi Maeda, Friedrich K. Roepke, Po-Sheng Ou, Sung-Han Tsai
ASIAA, HITS, NTU

We present new radiation hydrodynamic simulations of supernova shock breakout from blue supergiant (BSG) and red supergiants (RSGs) using the CASTRO code. We consider a range of circumstellar media (CSMs) produced by stellar winds to investigate how preexplosion mass loss affects shock breakout. The multigroup flux-limited diffusion scheme in CASTRO captures the interaction between the explosion shock, its radiation precursor, and the surrounding CSM. We find that strong radiation precursors, generated by radiation leakage behind the shock, can drive fluid instabilities and move the effective photosphere outward before the shock reaches the stellar surface. The resulting breakout emission is longer than previous one-dimensional models. The light-curve colors gradually evolve from blue to red after the peak. The dense CSM further extends the breakout rise time by increasing the photon diffusion. These results provide new constraints on stellar atmospheres and mass-loss histories prior to core collapse. Although our selected wavelength ranges fall outside the observational bands of missions such as the Einstein Probe and ULTRASAT, our study still provides valuable insights into the color evolution of shock breakout and can help guide the interpretation of future observations.