Reporters learned from the Yunnan Astronomical Observatory of the Chinese Academy of Sciences on the 31st that Dr. Li Zhenwei and his collaborators proposed a new formation mechanism of hot sub dwarfs, which provides a theoretical explanation for some observations of helium rich hot sub dwarfs. The international mainstream astronomical journal Astrophysics has published relevant results. Hot dwarf stars are a type of helium core burning stars, mostly found in binary systems. They are of great significance for understanding cutting-edge issues in the field of astronomy, such as the structural evolution of the Milky Way, and are important research objects in astronomy. Meanwhile, extremely short orbital period thermal dwarf binary stars are also an important type of gravitational wave source, and the gravitational wave radiation signals generated by them are expected to be captured by future space gravitational wave detectors. The mainstream research model suggests that when a star evolves into a red giant, it undergoes a binary interaction loss envelope at the top, ultimately producing a hot sub dwarf star, known as the red giant channel. However, this cannot explain the recently observed special hot sub dwarf star SMSSJ1920. This star is the third hot sub dwarf binary star discovered so far that is undergoing material transfer. About 10000 years ago, it underwent a common cladding ejection process. The typical evolution time scale of thermal sub dwarfs generated by the red giant channel is tens of millions of years, which is obviously inconsistent with the observation results. To explain the evolutionary origin of SMSSJ1920, researchers propose a new pathway for the formation of thermal sub dwarfs, where stars evolve into asymptotic giant branches with a common envelope, ultimately resulting in a thermal sub dwarf binary. This channel is also known as the asymptotic giant branch channel. Unlike thermal subdwarfs generated in the red giant channel, thermal subdwarfs generated in the asymptotic giant branch channel have carbon oxygen nuclei, helium shells, and hydrogen shells. Based on relevant numerical values, researchers have successfully constructed a thermal sub dwarf model generated by the asymptotic giant branch channel, and the new model can well explain the observational characteristics of SMSSJ1920. This new channel theory for the formation of thermal sub dwarfs provides new ideas for further understanding the evolutionary correlations of different types of thermal sub dwarfs. (Lai Xin She)