Sirius was often described as red in ancient western literature. Scholars have found such descriptions in the cuneiform clay tablets of ancient Babylon, as well as in the works of Ptolemy, Seneca, Cicero, Hakkas and other celebrities. In ancient Greece and Rome. 1985, W. Sehlosser and W. Bergnmma brought up the old story again and announced that they had found a work written by Gregory, Bishop of Tours (in present-day France) in an early medieval manuscript. The red star mentioned in it could be confirmed to be Sirius, so it was concluded that Sirius was still red until the end of the 6th century, and then turned white [1]. This triggered a new round of debate and concern about the color of Sirius. 〔2〕
According to the current star evolution theory and the current understanding of Sirius binary star, its star A is located in the main star sequence, and it is impossible to change color on the time scale of one or two thousand years. If Sirius was really red before the 6th century AD, theoretically the only possible way out is to turn our attention to the dim Sirius B: this star is a white dwarf, and this star will go through the red giant stage before it evolves into a white dwarf, which seems to hopefully explain the ancient western record that Sirius was red-that is, the magnificent red light of star B covered star A at that time. However, according to the current stellar evolution theory, even considering the extreme situation, it takes much longer than 1 500 years to evolve from a red giant to a white dwarf. Therefore, the ancient western record that Sirius is red has never been satisfactorily explained.
Therefore, astronomers can only face the following choices: either doubt the current theory of stellar evolution or deny the ancient saying that Sirius was red.
The authenticity of the color description of Sirius in the ancient west is not completely impeccable: seneca, Cicero, Flachs and others are either philosophers, political commentators or poets, and their astronomical attainments are difficult to prove; Although Ptolemy was a great astronomer, there are still some doubts in many specific links. As for the red star described by Gregory, many people think it is arcturus [3] instead of Sirius, who is a bright red giant.
On the other hand, as we all know, the ancient astronomy-astrology documents in China are rich, systematic and detailed in astronomical records. Therefore, it is necessary to turn to the early China ancient books for evidence. In order to ensure the authority of historical materials, this paper strictly limits the scope of investigation to ancient professional documents and does not involve philosophical or literary works.