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請回答第 46 題至第 48 題： A brown dwarf is a dim, hypothetical type of star that astronomers have long thought must exist, but firm proof that it does has so far eluded them. The problem is simply that, by definition, a brown dwarf is maddeningly difficult to see. So astronomers have resorted to rather indirect methods of detection. They have tried to find a dwarf whose gravity is causing a bright star nearby to wobble. Or they have picked a bright star that should be emitting a certain amount of light and looked to see if a dwarf companion is adding a little extra. Now the astronomer William Forrest of the University of Rochester has apparently succeeded in a direct approach: he says he has simply taken a picture of one—in fact, not just of one but of several. It was not quite as easy as it sounds. A brown dwarf has less than 8 percent of the sun’s mass, which means it is not massive enough to squeeze its core enough to keep fusion reactions going. In other words, it is not a proper star at all; the only radiation it gives off is heat left over from its birth in a collapsing cloud of interstellar gas. With no internal reactor, the star quickly cools and gets too dim and brown to see.
【題組】46 According to the passage, what does a brown dwarf refer to?
(A)A bright star
(B)A star eight times larger than the sun
(C)A dim mass with no internal reactor
(D)A star with fusion reactions going

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000 高二下 (2018/01/03)
They have tried to f☆☆☆ ☆ ☆☆☆☆☆...


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A 大四下 (2021/10/14)

A brown dwarf is a dim, hypothetical type of star that astronomers have long thought must exist, but firm proof that it does has so far eluded them. first sentence

elude  (巧妙地) 逃避，躲避▸   使困惑，難倒
dim 微暗的；暗淡的 ▸ 模糊的，朦朧的 


With no internal reactor, the star quickly cools and gets too dim and brown to see. Last sentence


請回答第 46 題至第 48 題： A brown dwarf is a d..-阿摩線上測驗