This comet appears to have undergone another massive outburst, this time on 2010 February 2 increasing in brightness by a factor of 30-40. The object is one of the largest active comets known. It follows a near-circular path about 6.2 AU from the Sun, i.e. well beyond the orbit of Jupiter. This is its fourth outburst of a similar magnitude in the past 8 years. The nucleus of the comet is probably about 50 km in size and its behaviour may be a consequence of its very slow rotation along with the fact that it appears to be rich in carbon monoxide, a very volatile gas. The outburst was discovered only a few hours after it had begun by amateur astronomer, Faustino Garcia of Asturias, Spain on February 2nd at 23:58 UT during the course of routine monitoring of several comets.
Note the stellar appearance of the pseudonucleus and associated faint diffraction spikes. The near-spherical expanding coma is about 12-13 arcsec across and has a noticeable assymmetry directed towards position angle 305 deg. The integrated V magnitude of the entire coma is 11.89 +/-0.05. There also appears to be a brighter inner envelope offset from the pseudonucleus, which may be associated with expanding dust. The outer envelope may be especially rich in gas and very fine dust.
Update 8 February 2010
Richard has taken further observations of the comet (image 2). Note that the view shown lies entirely within the bright expanding spherical coma. Application of a rotational filter using IRIS software has revealed details of discrete features close to the pseudonucleus, which is itself elongated in shape. The image is reminiscent of Comet 17P/Holmes after its unique outburst except that here the streamers of larger fragments appear to be travelling more slowly in somewhat opposing directions, although this may be an illusion caused by perspective. It should be possible to track the motion of these larger fragments over the coming few weeks.
| Details of first image | |
|---|---|
| Telescope | Faulkes Telescope North |
| Mid-exposure date: | 2010 February 3, 14:42 UT |
| Filters | 2 x 60-sec R-filter 1 x 90-sec V filter images tracked and stacked in Astrometrica and subjected to a logarithmic stretch in false (blue-white) color |
| Field of View | .5 x 1.9 arcmin |
| Seeing conditions | 1.8-2.0 arcsec FWHM |
| Image orientation | North Up, East left |
Many thanks to Richard Miles from British Astronomical Association for producing the image and text.
