2. 外语
  3. Hotter and more massive than the Sun, stars called “stragglers” are puzzling to astronomers because such rapidly burning stars w

Hotter and more massive than the Sun, stars called “stragglers” are puzzling to astronomers because such rapidly burning stars w

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问题     Hotter and more massive than the Sun, stars called “stragglers” are puzzling to astronomers because such rapidly burning stars would not be expected to persist in ancient star clusters. Some researchers believe that the typical blue stragglers formed when two ancient, lower-mass stars collide and merge form more massive, hotter star. Peter Leonard theorizes alternatively that in low density globular clusters, where mergers between single stars occur too infrequently to account for the observed quantity of blue stragglers, these stragglers are created instead by a group of stars. He suggests that a pair of stars already orbiting each other presents a larger target for a third star or another pair. Once this new grouping forms, close encounters between the stars could prompt any two to merge as a blue straggler. Leonard’s model predicts that each blue straggler has a distant orbiting companion—as appears true of many blue stragglers in the M67 cluster of the Milky Way galaxy.
The passage cites which of the following as evidence undermining the theory presented in the second sentence?
选项 A、A discrepancy between the number of mergers between single stars in certain low-density globular clusters and that in other low-density globular clusters
B、A discrepancy between the heat and mass of blue stragglers formed by one type of process and the heat and mass of blue stragglers formed by another type of process
C、A discrepancy between the frequency of star mergers in low-density globular clusters and those in high-density globular clusters
D、A discrepancy between the amount of heat and mass of ancient single stars and that of blue stragglers
E、A discrepancy between the number of mergers between single stars in certain star clusters and the number of blue stragglers in those clusters
答案E
解析 本题考查对老观点的批判原理。老观点被反驳的原因就是理论推断出的蓝色离散星的数量和实际观察到的蓝色离散星数量不符，因此选项E正确。
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本试题收录于： GRE VERBAL题库GRE分类
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