GRE阅读高频机经原文：蓝脱序星的两种形成过程
<p> 34. 蓝脱序星<span word="blue">blue</span> <span word="straggler">straggler</span>的两种形成过程</p><p> <span word="Vampires">Vampires</span> <span word="and">and</span> <span word="collisions">collisions</span> <span word="rejuvenate">rejuvenate</span> <span word="stars">stars</span></p><p> <span word="Using">Using</span> <span word="the">the</span> <span word="NASA">NASA</span>/<span word="ESA">ESA</span> <span word="Hubble">Hubble</span> <span word="Space">Space</span> <span word="Telescope">Telescope</span>, <span word="astronomers">astronomers</span> <span word="have">have</span> <span word="uncovered">uncovered</span> <span word="two">two</span> <span word="distinct">distinct</span> <span word="kinds">kinds</span> <span word="of">of</span> <span word="rejuvenated">rejuvenated</span> <span word="stars">stars</span> <span word="in">in</span> <span word="the">the</span> <span word="globular">globular</span> <span word="cluster">cluster</span> <span word="Messier">Messier</span> 30. <span word="A">A</span> <span word="new">new</span> <span word="study">study</span> <span word="shows">shows</span> <span word="that">that</span> <span word="both">both</span> <span word="stellar">stellar</span> <span word="collisions">collisions</span> <span word="and">and</span> <span word="a">a</span> <span word="process">process</span> <span word="sometimes">sometimes</span> <span word="called">called</span> <span word="vampirism">vampirism</span> <span word="are">are</span> <span word="behind">behind</span> <span word="this">this</span> <span word="cosmic">cosmic</span> <span word="face">face</span> <span word="lift">lift</span>. <span word="The">The</span> <span word="scientists">scientists</span> <span word="also">also</span> <span word="uncover">uncover</span> <span word="evidence">evidence</span> <span word="that">that</span> <span word="both">both</span> <span word="sorts">sorts</span> <span word="of">of</span> <span word="blue">blue</span> <span word="stragglers">stragglers</span> <span word="were">were</span> <span word="produced">produced</span> <span word="during">during</span> <span word="a">a</span> <span word="critical">critical</span> <span word="dynamical">dynamical</span> <span word="event">event</span> <span word="that">that</span> <span word="occurred">occurred</span> <span word="in">in</span> <span word="Messier">Messier</span> 30 <span word="a">a</span> <span word="few">few</span> <span word="billion">billion</span> <span word="years">years</span> <span word="ago">ago</span>.</p><p> <span word="Stars">Stars</span> <span word="in">in</span> <span word="globular">globular</span> <span word="clusters">clusters</span> <span word="are">are</span> <span word="generally">generally</span> <span word="extremely">extremely</span> <span word="old">old</span>, <span word="with">with</span> <span word="ages">ages</span> <span word="of">of</span> 12-13 <span word="billion">billion</span> <span word="years">years</span>. <span word="However">However</span>, <span word="a">a</span> <span word="small">small</span> <span word="fraction">fraction</span> <span word="of">of</span> <span word="them">them</span> <span word="appear">appear</span> <span word="to">to</span> <span word="be">be</span> <span word="significantly">significantly</span> <span word="younger">younger</span> <span word="than">than</span> <span word="the">the</span> <span word="average">average</span> <span word="population">population</span> <span word="and">and</span>, <span word="because">because</span> <span word="they">they</span> <span word="seem">seem</span> <span word="to">to</span> <span word="have">have</span> <span word="been">been</span> <span word="left">left</span> <span word="behind">behind</span> <span word="by">by</span> <span word="the">the</span> <span word="stars">stars</span> <span word="that">that</span> <span word="followed">followed</span> <span word="the">the</span> <span word="normal">normal</span> <span word="path">path</span> <span word="of">of</span> <span word="stellar">stellar</span> <span word="evolution">evolution</span> <span word="and">and</span> <span word="became">became</span> <span word="red">red</span> <span word="giants">giants</span>, <span word="have">have</span> <span word="been">been</span> <span word="dubbed">dubbed</span> <span word="blue">blue</span> <span word="stragglers">stragglers</span> . <span word="Blue">Blue</span> <span word="stragglers">stragglers</span> <span word="appear">appear</span> <span word="to">to</span> <span word="regress">regress</span> <span word="from">from</span> <span word="old">old</span> <span word="age">age</span> <span word="back">back</span> <span word="to">to</span> <span word="a">a</span> <span word="hotter">hotter</span> <span word="and">and</span> <span word="brighter">brighter</span> <span word="youth">youth</span>, <span word="gaining">gaining</span> <span word="a">a</span> <span word="new">new</span> <span word="lease">lease</span> <span word="on">on</span> <span word="life">life</span> <span word="in">in</span> <span word="the">the</span> <span word="process">process</span>. <span word="A">A</span> <span word="team">team</span> <span word="of">of</span> <span word="astronomers">astronomers</span> <span word="used">used</span> <span word="Hubble">Hubble</span> <span word="to">to</span> <span word="study">study</span> <span word="the">the</span> <span word="blue">blue</span> <span word="straggler">straggler</span> <span word="star">star</span> <span word="content">content</span> <span word="in">in</span> <span word="Messier">Messier</span> 30, <span word="which">which</span> <span word="formed">formed</span> 13 <span word="billion">billion</span> <span word="years">years</span> <span word="ago">ago</span> <span word="and">and</span> <span word="was">was</span> <span word="discovered">discovered</span> <span word="in">in</span> 1764 <span word="by">by</span> <span word="Charles">Charles</span> <span word="Messier">Messier</span>. <span word="Located">Located</span> <span word="about">about</span> 28 000 <span word="light">light</span>-<span word="years">years</span> <span word="away">away</span> <span word="from">from</span> <span word="Earth">Earth</span>, <span word="this">this</span> <span word="globular">globular</span> <span word="cluster">cluster</span><span word="a">a</span> <span word="swarm">swarm</span> <span word="of">of</span> <span word="several">several</span> <span word="hundred">hundred</span> <span word="thousand">thousand</span> <span word="stars">stars</span><span word="is">is</span> <span word="about">about</span> 90 <span word="light">light</span>-<span word="years">years</span> <span word="across">across</span>.</p><p> <span word="Although">Although</span> <span word="blue">blue</span> <span word="stragglers">stragglers</span> <span word="have">have</span> <span word="been">been</span> <span word="known">known</span> <span word="since">since</span> <span word="the">the</span> <span word="early">early</span> 1950<span word="s">s</span>, <span word="their">their</span> <span word="formation">formation</span> <span word="process">process</span> <span word="is">is</span> <span word="still">still</span> <span word="an">an</span> <span word="unsolved">unsolved</span> <span word="puzzle">puzzle</span> <span word="in">in</span> <span word="astrophysics">astrophysics</span>. <span word="Its">Its</span> <span word="like">like</span> <span word="seeing">seeing</span> <span word="a">a</span> <span word="few">few</span> <span word="kids">kids</span> <span word="in">in</span> <span word="the">the</span> <span word="group">group</span> <span word="picture">picture</span> <span word="of">of</span> <span word="a">a</span> <span word="rest">rest</span>-<span word="home">home</span> <span word="for">for</span> <span word="retired">retired</span> <span word="people">people</span>. <span word="It">It</span> <span word="is">is</span> <span word="natural">natural</span> <span word="to">to</span> <span word="wonder">wonder</span> <span word="why">why</span> <span word="they">they</span> <span word="are">are</span> <span word="there">there</span>, <span word="says">says</span> <span word="Francesco">Francesco</span> <span word="Ferraro">Ferraro</span> <span word="from">from</span> <span word="the">the</span> <span word="University">University</span> <span word="of">of</span> <span word="Bologna">Bologna</span> <span word="in">in</span> <span word="Italy">Italy</span>, <span word="lead">lead</span> <span word="author">author</span> <span word="of">of</span> <span word="the">the</span> <span word="study">study</span> <span word="that">that</span> <span word="will">will</span> <span word="be">be</span> <span word="published">published</span> <span word="this">this</span> <span word="week">week</span> <span word="in">in</span> <span word="Nature">Nature</span> . <span word="Researchers">Researchers</span> <span word="have">have</span> <span word="been">been</span> <span word="studying">studying</span> <span word="these">these</span> <span word="stars">stars</span> <span word="for">for</span> <span word="many">many</span> <span word="years">years</span> <span word="and">and</span> <span word="knew">knew</span> <span word="that">that</span> <span word="blue">blue</span> <span word="stragglers">stragglers</span> <span word="are">are</span> <span word="indeed">indeed</span> <span word="old">old</span>. <span word="They">They</span> <span word="were">were</span> <span word="thought">thought</span> <span word="to">to</span> <span word="have">have</span> <span word="arisen">arisen</span> <span word="in">in</span> <span word="a">a</span> <span word="tight">tight</span> <span word="binary">binary</span> <span word="system">system</span> . <span word="In">In</span> <span word="such">such</span> <span word="a">a</span> <span word="pair">pair</span>, <span word="the">the</span> <span word="less">less</span> <span word="massive">massive</span> <span word="star">star</span> <span word="acts">acts</span> <span word="as">as</span> <span word="a">a</span> <span word="vampire">vampire</span>, <span word="siphoning">siphoning</span> <span word="fresh">fresh</span> <span word="hydrogen">hydrogen</span> <span word="from">from</span> <span word="its">its</span> <span word="more">more</span> <span word="massive">massive</span> <span word="companion">companion</span> <span word="star">star</span>. <span word="The">The</span> <span word="new">new</span> <span word="fuel">fuel</span> <span word="supply">supply</span> <span word="allows">allows</span> <span word="the">the</span> <span word="smaller">smaller</span> <span word="star">star</span> <span word="to">to</span> <span word="heat">heat</span> <span word="up">up</span>, <span word="growing">growing</span> <span word="bluer">bluer</span> <span word="and">and</span> <span word="hotter">hotter</span><span word="behaving">behaving</span> <span word="like">like</span> <span word="a">a</span> <span word="star">star</span> <span word="at">at</span> <span word="an">an</span> <span word="earlier">earlier</span> <span word="stage">stage</span> <span word="in">in</span> <span word="its">its</span> <span word="evolution">evolution</span>.</p>
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