Spectroscopy of comet C/2004 Q2 (Machholz)

Based on our observations, we determined the mixing ratios of the molecules relative to H_2_O in C/2004 Q2. C/2004 Q2 might be the intermediate type between Oort Cloud and Jupiter Family comets.

To investigate the formation conditions of such intermediate type comet, we focused on the (C_2_H_2_+C_2_H_6_)/H_2_O ratios and C_2_H_6_/(C_2_H_6_+C_2_H_2_) ratios in comets from the viewpoint of conversion from C_2_H_2_ to C_2_H_6_ in the precometary ices. We employed the dynamical-evolutional model and the chemical-evolutional model to determine the formation region of C/2004 Q2 more precisely. We found that comet C/2004 Q2 might have formed in relatively inner region of the solar nebula than the typical Oort Cloud comet (but slightly further than 5AU from the proto-Sun).