超新星是宇宙中最剧烈的恒星级爆发现象之一，其峰值光度与整个星系的光度相当。核坍缩型超新星发生在大质量恒星演化的最后阶段，当核聚变无法抵抗核心自身引力时，恒星核心将发生坍塌，产生超新星爆发。由于其物理过程非常极端，爆发过程中的诸多细节目前仍不完全清楚，是天体物理学的前沿问题之一。

        2023年5月19日，Koichi Itagaki探测到来自M101星系的SN 2023ixf超新星爆发。M101星系是云南大学1.6米多通道测光巡天望远镜（Mephisto）的监测目标。2023年5月20日以来，Mephisto对最新爆发的2023ixf超新星持续开展多波段同时观测。目前已积累十余天的观测数据，总曝光次数已达到约650次。该超新星距离地球约2.1千万光年，是近十年以来爆发的一颗距离地球最近的核坍缩型超新星。利用Mephisto的多波段同时高精度观测数据，我们期待能够对核坍缩超新星前身星性质以及爆发机制给出有力的约束。

图1. 近邻星系M101 uvr三波段真彩色合成图。左：超新星爆发前的图像；右：超新星爆发后的图像。

Fig.1. uvr-bands composite image of neighboring galaxy M101. Left: Image before SN 2023ixf explosion. Right: Image after SN 2023ixf explosion. 

    Supernovae are one of the most violent explosive phenomena in the universe. The peak luminosity of a supernova is comparable to the luminosity of the entire galaxy. Core-collapse supernovae occur in the final stage of the evolution of massive stars. When the radiation pressure from nuclear fusion in the core cannot resist its own gravity, the star core collapses, resulting in supernova explosion. Due to the extreme physical process of supernovae, many details of the explosion process are still not well understood, which is one of the frontier issues of astrophysics.

    Koichi Itagaki detected an SN 2023ixf supernova explosion from the M101 galaxy on May 19, 2023. M101 galaxy is one of the monitoring objectives of Mephisto. Since May 20, 2023, Mephisto has conducted simultaneous multi-band observations of this new supernova SN 2023ixf. Currently, the observations are still going on, and about 650 exposures have been achieved. This supernova, which is 21 million light-years away, is the closest core-collapsed supernova to Earth discovered in a decade. Based on the high quality and simultaneous multi-band imaging data from Mephisto, it is expected that stronger constraints can be put on the progenitor and explosion mechanism of core-collapse supernovae.