Friday, February 27, 2009

Changing geometry of comet C/2007 N3 (LULIN)

During the past few nights, we witnessed a dramatic change of the viewing geometry of comet LULIN: its ion tail switched its position from North-West, and is currently hidden behind the coma. However this phenomena doesn't change that much the visibility of some details within the inner coma of the comet.

Here you can find an image obtained on 2009, feb. 27 (details in caption):

http://tinyurl.com/av6q5e

Comparison with a similar image, obtained on 2009, Feb. 19:

http://tinyurl.com/bhku68

show the persistence of some asymmetries in the inner coma. In particular, a kind of "fan" toward PA200 deg, with a second, similar structure (but less evident) in the opposite direction, toward PA 20 deg. It's not clear yet the explanation of this features; what we can say at the moment, is that they doesn't seem to be artefacts (i.e. artificially generated features using image processing softwares) and that they show no significant changes in spite of the significative change of our perspective angle.

by Ernesto Guido, Giovanni Sostero and Paul Camilleri

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