Today we wanted to make some wide-field imaging of comet C/2007 N3 (LULIN), in search for large scale structural features. In our image (see below, details in the caption; click on it for a bigger version):
is clearly visible the characteristic dichotomy of this comet: a dusty anti-tail pointing toward the Sun (i.e. to South-East) and the highly structured ion (plasma) tail toward West,Northwest. This uncommon configuration, is due to the particular geometric circumstances occuring during these nights, with the comet seen nearly head-on as seen from Earth.
Moreover, we were lucky enough to capture an intriguing phenomena: in our images is clearly visible a nice disconnection event (DE) in the plasma tail of the comet (evidenced by a red circle in this rendition):
The DE indicates that the comet has recently passed through a disturbance in the magnetic field carried by the solar wind, that destroyed the original plasma tail, creating a new one. The separation of the two ion tails indentified by the DE, is visible in our image as a kind of elongated and diffuse "knot" along the plasma tail.
A 3x zoomed view of this feature is available here:
The "knot" is dragged tailward by the solar wind, and will dissipate soon. More events like this are expected in the near future, when comet LULIN will approah Earth. Comet aficionados, heads-up!
by Ernesto Guido, Giovanni Sostero and Paul camilleri