彗星67P 上的灰塵噴流與質量傳輸;Dust Jets and Mass Transport of Comet 67P/Churyumov–Gerasimenko

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Title:	彗星67P 上的灰塵噴流與質量傳輸;Dust Jets and Mass Transport of Comet 67P/Churyumov–Gerasimenko
Authors:	賴彥霖;Lai, Ian-Lin
Contributors:	太空科學研究所
Keywords:	彗星;羅賽塔;直接模擬蒙地卡羅法;comets;Rosetta;DSMC
Date:	2019-01-17
Issue Date:	2019-04-02 14:20:23 (UTC+8)
Publisher:	國立中央大學
Abstract:	羅賽塔太空船在彗星67P上近距離觀測到許多有趣的現象，太陽加熱不規則彗核上的揮發物昇華並產生氣體噴流，夾帶著灰塵粒子形成一束束的灰塵噴流，太空船上搭載的OSIRIS光學照相機觀測到許多灰塵噴流從彗核表面射出，因此可以從影像定位出些噴流在彗星上的位置。我們找出了這些灰塵噴流的來源會隨著太陽照射的位置而改變並且與附近地貌有關。此外，我們也研究灰塵粒子隨著彗星噴氣的牽引力而移動，有些會再度掉回到彗星表面，其中主要是由南半球向著北半球方向的傳輸。;Rosetta spacecraft observations at close distance have shown many interesting phenomenon on Comet 67P/ Churyumov–Gerasimenko. Gas outflow could drag dust grains as indicated by the collimated dust jet structures on the sunlit side because of the diurnal thermal cycle and the irregular shape of the nucleus. The OSIRIS imaging observations show that the dust coma was filled by numerous dust jets emanating from the nucleus surface. This means that they can be used to trace the active regions as the comet moved around the perihelion. In this work, we show the source regions of dust jets would move in consonance with the sunlit belt. Therefore, a number of source regions characterized by repeated jet activity could be identified which might be the result of local topographical variations or chemical heterogeneities. With a time variability model of the global gas production rate, we also investigate the transport of dust grains calculated by dust particle dynamics under the influences of the rotating nucleus and gas dragging force. From these considerations, we find a redeposition of the ejected dust grains from the southern hemisphere to the northern hemisphere during the southern summer season.
Appears in Collections:	[Graduate Institute of Space Science] Department of Earth Sciences

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