Update on Comet 29P - 17/02/10
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This third outburst is quite a weak affair, so much so that today we have had to stack 35 one-minute exposures to build up enough signal so that we can confidently measure the motion of the ejected material. Thanks to everyone for securing the large number of images with the FTS. Unfortunately only 3 images were taken with the FTN partly through interruptions due to high wind speed on Haleakala and so these are not sufficient in number for our purpose. Also, the seeing today was not as good as yesterday.
Having images from two observing epochs enables the motion to be extrapolated back to the position of the nucleus so that the time of outburst can be calculated. This turns out to have occurred on February 15 at around 17+/-2 hr UT. In this third outburst, material has spewed out into space mainly in one direction at an average speed of 112 (+/-11) m/s as projected onto the plane of the sky. Debris moving at speeds up to at least 150 m/s is also evident.
There is also another lesser stream moving somewhat opposite in direction to the main one but this could be because the main vector of its motion is towards the Earth and so as it is very close to the nucleus most of it disappears when the rotational filter is applied. There is also a weak arc of material connecting the two streams, which itself is expanding outwards at about 100 m/s.
