A spectrophotometric study of the COMA of COMET C/2001 A2 (LINEAR)

Low-resolution spectrographic observations of comet C/2001 A2 (LINEAR) were carried out between 2001 July 5 and 9 at Beijing Astronomical Observatory using its 2.16 m telescope. From the spatial distributions of the brightness profiles of C₂, C₃, CN, NH₂, and the dust continuum, we are able to trace the source regions of these cometary radicals and their parent molecules. The CN emission displayed a remarkable asymmetry, with its intensity peak shifted 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 CN has a distributed source not necessarily associated with the central nucleus. A probable release mechanism is associated with a CN jet structure detected in imaging photometric measurements.