The Rotation of Comet Machholz (C/2004 Q2)

This page contains links to two "movies" of comet Machholz (C/2004 Q2). Each movie shows a sequence of images that have been phased to represent one rotation of the nucleus (with a period of 17.6 hours). The data presented here is discussed more fully in our paper Cyanogen Jets and the Rotation State of Comet Machholz (C/2004 Q2) By Tony Farnham, Nalin Samarasinha, Beatrice Mueller and Matttew Knight.

These movies were made from images obtained with the HB narrowband CN filter, which isolates light emitted by the cyanogen molecule. The comet's nucleus is in the center of the image, and the bright central peak of the coma has been removed by dividing out an azimuthally averaged radial profile. This enhancement reveals the changes that take place as the nucleus rotates.

In both sequences, two jets can be seen, pointing in roughly opposite directions. These jets oscillate back and forth during a rotation, and the material they emit expands outward with time. Stars can be seen as streaks in some of the images.

The sequences can be looped to simulate continuous rotational changes.

March 2005 Rotational sequence from 11-14 March 2005. (922 KB)

April 2005 Rotational sequence from 9-14 April 2005. (844 KB)

Last modified: June 12, 2006

email: farnham@astro.umd.edu