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脈沖星

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2017-10-13 15:02China Daily Editor: Yao Lan ECNS App Download

脈沖星

pulsar

10月10日,中國科學院國家天文臺宣布,500米口徑球面射電望遠鏡(FAST)經過一年調試,已實現指向、跟蹤、漂移掃描等多種觀測模式的順利運行,并確認多顆新發現脈沖星.

After one year of trial operation, China's Five-hundred-meter Aperture Spherical Radio Telescope (FAST), the world's largest single-dish radio telescope, has identified multiple pulsars, the National Astronomical Observatories of China (NAOC) said Tuesday.

10月10日,中國科學院國家天文臺宣布,經過一年調試,500米口徑球面射電望遠鏡(FAST)已發現多顆脈沖星.FAST是世界上最大的單口徑射點望遠鏡.

Two of the pulsars, named J1859-01 and J1931-01, are 16,000 light years and 4,100 light years from Earth with rotation periods of 1.83 seconds and 0.59 seconds, respectively.

新發現的脈沖星中有兩顆分別為J1859-01和J1931-01,前者距離地球1.6萬光年,自轉周期1.83秒,后者距離地球4100光年,自轉周期0.59秒.

據科學家介紹,脈沖星(pulsar)是一種高速自轉的中子星(neutron star),由恒星演化和超新星爆發產生.它的密度極高(super density),每立方厘米重達上億噸,一塊方糖大小就相當于地球上一萬艘萬噸巨輪的重量.脈沖星自轉速度很快(fast rotational speed)、自轉周期精確(accurate rotation period),是宇宙中最精準的時鐘.這一特殊"本領",讓脈沖星在計時、引力波探測(finding gravitational waves)、航天器導航(navigating spacecraft)等領域具有重要應用.

這兩顆脈沖星J1859-01和J1931-01分別由"中國天眼"于今年8月22日、25日在南天銀道面(the southern galactic plane)通過漂移掃描(drift-scanning)發現.目前"天眼"已探測到數十個優質脈沖星候選體(promising pulsar candidates),其中6顆通過國際認證.

對于觀測范圍可達已知宇宙邊緣的"天眼"來說,發現脈沖星只是使命之一,未來,它還將在中性氫觀測(neutral hydrogen observation)、譜線觀測(spectrum observation)、尋找可能的星際通訊信號(exploration of interstellar communication signals)等方面大放異彩.

2016年9月25日,我國500米口徑球面射電望遠鏡(FAST)正式落成啟用,位于貴州省平塘縣名為大窩凼的喀斯特洼地(naturally deep and round karst depression)之中.其接收面積(receiving area)相當于30個足球場大?鞘瀾繾畬蟮牡タ誥渡淶繽毒?射電望遠鏡(radio telescope)接收的是肉眼看不到的射電波(radio waves),跟接收衛星信號的天線鍋類似,通過鍋的反射聚焦,把幾平方米到幾千平方米的信號聚攏到一點上.因此,FAST的工作不是"看",而是"聽",依靠500米口徑的"大耳朵"來"收聽"太空深處物體發出的無線電波.

 

  

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