Recently, the researchers of Yunnan Observatory of the Chinese Academy of Sciences reproduced the quasi periodic light variation curve of the ultra soft X-ray source by simulating the feedback of white dwarfs on the periodic mass transfer driven by the companion star of X-ray irradiation, which provides a new way to explain the origin of the quasi periodic light variation curve of the ultra soft X-ray source and the research of the predecessor stars of Ia type supernova. This achievement was published in the International Astronomical Journal "Astronomy and Astrophysics". Type Ia supernova is recognized as the "standard candle" of the universe. In the 1990s, people used it to find that the universe was expanding rapidly, which meant that there was dark energy in the universe. This discovery posed a great challenge to basic physics research. Now, people use it to measure cosmological parameters, so as to test the evolution of dark energy equation of state with time. "At present, the predecessor of type Ia supernova is still unclear, which may hinder the development of accurate cosmology." Meng Xiangcun, a researcher at Yunnan Observatory, said that the super soft X-ray source is considered to be the most likely predecessor of type Ia supernova. The super soft X-ray source is composed of a white dwarf star and a massive main sequence companion star. The white dwarf accretes the material from the companion star and continuously increases its own mass until its mass reaches the Chandraseka mass limit, thus causing the explosion of type Ia supernova. The light variation curve of the ultra soft X-ray source shows a quasi periodic change of alternating light and dark. However, the cause of this quasi periodic variation curve of ultra soft X-ray source is still unclear. In previous studies on the origin of this quasi periodic light variation curve, the illumination of the companion star by ultra soft X-ray was ignored. For this reason, Zhao Weitao, a doctoral student of Yunnan Observatory, and Meng Xiangcun, a researcher, proposed that the companion star would expand and contract periodically through the periodic irradiation of ultra soft X-ray. Therefore, the mass transfer rate of the binary stars increases and decreases periodically, leading to the periodic expansion and contraction of the white dwarf star's photosphere layer, which reproduces the light variation curve of the ultra soft X-ray source. This result provides a new way to explain the origin of the quasi periodic light variation curve in the ultra soft X-ray source, and also provides a new idea for the research of the predecessor stars of type Ia supernova. (Outlook New Times)