A Study of Cometary Comae of Split Comets

• Main Authors: Zhong-Yi Lin, 林忠義
• Other Authors: 葉永烜
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/40984879840271436647

博士 === 國立中央大學 === 天文研究所 === 95 === The splitting of comets has been observed many times. These fragmentation events can be roughly divided into four types. One the split comets disappeared completely (C/1999 S4 LINEAR); two the comet was destroyed during its impact with Jupiter (D/1993 F2 Shoemaker-Levy 9); the third where fragments have remained for a long time (73P/Schwassmann-Wachmann 3); and the fourth the comets suffered several minor fragmentations (C/2004 Q2 Machholz). In this study, we used low-resolution spectrographic and photometry imaging to investigate the activity coma of natural and artificial outburst events. We found that the CN emission of comet 2001 A2 LINEAR displayed remarkable asymmetry, with its intensity peak shiftting to the tailward side by as much as 1000 km away from the center of the dust continuum. There is thus a strong indication that the source of CN distribution was due to the spliting event and not necessarily associated with the central nucleus. A probable release mechanism is associated with the CN jet structure detected in the imaging photometric measurements. Two jets observed for comet C/2004 Q2 Machholz were observed in the coma distributions of C2 and CN of comet Machholz that were not formed in the dust coma. The jets were spiral-like in structure and were angled differently at different observing times. The formation of these jets can be explained by the presence of two active surface regions on the rotating cometary nucleus. Arclets structures are found in comet 73P/Schwassmann-Wachmann 3B after the splitting event and the sources produced a lot of dust and gas particles come from the boulder train (fiant-fragments). Althoughc there were no fragments found in the artificial outburst event, the result still provide us with a much better understanding of the physical structure of the surface of comet Tempel 1.