The observations of Comet C/2007 N3 (Lulin) from SLT at Lulin Observatory.

Abstract

The green comet C/2007 N3 (Lulin) is a new Oort cloud comet which has retrograde orbit (inclination = 178°). It reached its perihelion on January 10, 2009, and the closest distance to Earth was 0.411 AU on February 24. Soon after its discovery on July 11, 2007, the coma activity of comet Lulin was monitored closely by SLT 41-cm telescope until April 2009. After long time monitoring of comet Lulin the dust production rates (A(θ)fρ) was estimated. We discovered the anti-tail in the end of Dec. 2008 and this anti-tail were last for quite a while due to an effect of the orbital geometry. We also found the coincidence between the jet activity and the peak of A(θ)fρ values and this is a clue for us to realize what happens in dust coma of comet Lulin. 來自於歐特雲並擁有著逆行軌道（傾角~178度，軌道傾角大於90度稱之逆行）的鹿林彗星(C/2007 N3)是一顆長週期的綠色彗星。它所呈現的綠色代表著從彗星核心正噴出大量的氣體，例如氰(CN)與雙原子碳(C2)。這顆彗星於2009年1月10日到達近日點，並於2月24日通過近地點(0.411AU)。其實早在2007年7月11日發現鹿林彗星後（當時彗星距離太陽有6.36AU，離地球也有5.65AU的距離），我們就開始利用當初發現它的鹿林天文台SLT望遠鏡密切地持續觀察此彗星的發展。經分析SLT長期觀測資料，可粗略獲得鹿林彗星的灰塵粒子產生率(A( )f )與日心距離的關係圖。此外，我們也在2008年年底發現了不尋常的反向彗尾！經由影像分析後，發現彗星中的噴流結構似乎與灰塵分子產生率有某種關連性，而這線索或許能幫我們瞭解彗星的彗核在這段監測期間所發生的變化，例如彗核爆發伴隨著噴流產生等現象。