Title: Exploring the Mass Loss History and Shock Breakout Signals of Supernovae

Speaker: 张居甲

Institute: 云南天文台

Host: 林巍莉

Time: 2025.9.25 周四 14:30

Location: 物理楼 552

Abstract: 

Supernovae, the catastrophic explosions marking the final stages of stellar evolution, are intricately linked to Nobel Prize discoveries such as gravitational waves, neutrinos, cosmic acceleration, and compact object formation. They also play climacteric roles in cosmic chemical evolution and the origins of planetary systems. However, our understanding of fundamental questions—such as the progenitor-explosion connection and explosion mechanisms—remains incomplete, limiting progress in supernova research and related fields. A critical pathway to addressing these challenges is the study of extreme physical processes during the earliest phases of supernova explosions, particularly shock breakout and circumstellar material (CSM) structures. This talk will present results from high-cadence observations of nearby supernovae, including the first spectroscopic detection of shock breakout signals and the reconstructed mass-loss history of progenitors. These findings reveal how shocks propagate through asymmetric CSM and quantify the dramatic surge in mass-loss rates of red supergiants before the explosion, offering new insights into the dynamic interplay between stellar evolution and explosion physics.

Bio: 

Zhang Jujia is a Professor and PhD Supervisor at the Yunnan Observatories, Chinese Academy of Sciences (CAS). He is also a member of the CAS Youth Innovation Promotion Association and a recipient of the Yunnan Provincial Outstanding Youth Fund. He designed and led the Lijiang One Hour per Night Supernova (LiONS) program at the Lijiang 2.4-meter Telescope. The program has identified over 300 new supernova candidates, 60% of which were detected during their earliest explosive phases. Based on early observations, he has made significant contributions to understanding the diverse origins of supernovae and probing extreme physical processes. He has published more than 100 SCI-indexed papers, which have received over 3,000 citations, and has an H-index of 34.

Reference:

https://ui.adsabs.harvard.edu/abs/2023SciBu..68.2548Z/abstract

https://ui.adsabs.harvard.edu/abs/2024ApJ...970L..18Z/abstract

https://ui.adsabs.harvard.edu/abs/2025ApJ...978..163Z/abstract