Friday, September 4, 2009

Update about the unusual activity of 217P/LINEAR

We post here an update about the unusual activity of 217P/LINEAR (see our previous post ). We did not use invasive image processing routines (as the Larson-Sekanina filtering) in order to minimize the risk of introducing any artefact in the images. In the panels you will find only ordinary grayscale palette images, azimuthal median subtractions and 1/r theoretical coma subtractions, in order to enhance inner coma details:

2009 Aug. 15, David Cardenosa:

2009 Aug. 20, Michael Jaeger:

2009 Aug. 21, David Cardenosa:

2009 Aug. 22, David Cardenosa:

2009 Aug 22, Guido-Sostero:

2009, Sept.3, Paul Camilleri:

Central condensation evolution during the rise of the phenomena:

From what is possible to see from the above images, we might bracket the rise of the event between Aug. 20 and Aug. 21. It had a rather quick evolution (matter of hours) and then it settled down in some days.

We would exclude a foreshortening effect. In our opinion we have witnessed a transient phenomena that has interested the nucleus of the comets and/or its surroundings for a relatively short time. Currently (i.e. after a couple of weeks from the event) the comet seems to have recevered to its pre-something occurence.

We are grateful with the authors of the images.

by Giovanni Sostero & Ernesto Guido

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