Download In the Belly of the Beast

In the Belly of the Beast
2 August 2006
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每天晚上穿越行星, 天文學家使用最先進的儀器to tease away
new details about宇宙, 並且有時候他們盡力捕捉一些相當奇
妙的事件. Take the case of WD0137-349, a collapsed star
known as a white dwarf. 以由the European Southern
Observatory‘s Very Large Telescope in Chile所收集的軌跡及溫
度資料為依據, 一個研究團隊已經決定當WD0137-349 was a
much bigger red giant star, it swallowed a nearby planet like
object called a brown dwarf, which miraculously survived the
experience.
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這之間的關係並不總是如此的混亂. Once, the two objects
were as far apart as Earth and the sun. 但當恆星接近其生命
終點時, 他膨脹到比原始大小的100倍大, becoming a
hydrogen-filled red giant big enough to overtake the brown
dwarf. As the brown dwarf plowed through the red giant's
atmosphere, it began to orbit the giant less quickly, drawing the
two objects closer together. They now circle each other at a
distance of only about 400,000 kilometers, or about the space
between Earth and the moon.
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儘管如此, there‘s the question of how the brown dwarf made it
out alive. 這答案, says team member Matt Burleigh of the
University of Leicester in the United Kingdom, is that the red
giant’s mostly hydrogen atmosphere was much less dense than
the brown dwarf‘s mostly nitrogen envelope. 此外, the team
reports tomorrow in Nature, the engulfment lasted for only a
few thousand years--a wink of an eye in cosmic timeframes.
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Though the brown dwarf survived no worse for wear, the same
could not be said for the red giant. "The shock waves generated
by this encounter ripped apart the red giant," says lead researcher
Pierre Maxted of Keele University, also in the U.K. What's left is
a rather odd combination of a Jupiter-sized planet closely
orbiting a terrestrial-sized but more massive star.
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天文學家Mario Livio of the Space Telescope Science
Institute in Baltimore,美國馬里蘭州, 認為此發現 “相當
具有說服力的” 並說 it shows that objects other than black
holes and pulsars can survive a plunge through the interior
of a giant star. 他說此研究下一必然的步驟即是找出是否
brown dwarfs that have undergone such a swallowing
process are any different from their uningested counterparts.
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