Recent Outburst of Comet 29P/Schwassmann-Wachmann

Comet 29P/Schwassmann-Wachmann 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.

In observations taken of this comet by Richard Miles of the British Astronomical Association, the stellar appearance of the pseudonucleus and associated faint diffraction spikes can be seen (see image below).  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.

Details of the image shown:

2.0-m Faulkes Telescope North
Mid-exposure time:  2010 February 03 14:42 UT
2 x 60-sec R-filter and 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 = 1.5 x 1.9 arcmin
Seeing 1.8-2.0 arcsec FWHM
Image orientation North up, normal

Richard Miles
British Astronomical Association