TOEFL Listening: ETS-TOEFL听力机经 - W9TE_3Z333441112P$

According to the professor, what used to be a problem for astronomers when a new star was discovered? A. Determining whether the new star could be part of an asterism B. Ranking the new star's importance among the stars that are visible through telescopes C. Describing the new star's location so that other astronomers could find it D. Convincing the International Astronomical Union to accept the name proposed for the new star