comet 29P/Schwassmann-Wachmann
The British Astronomical Association (BAA) is reporting a new outburst of cryovolcanic comet 29P/Schwassmann-Wachmann. On Nov. 22nd, amateur astronomer Patrick Wiggins watched 29P increase in brightness by more than 4 magnitudes--a sign that a major eruption was in progress. On Nov. 23rd, André Debackère used the Faulkes Telescope North in Hawaii to photograph the expanding shell of debris:

The Pac-Man shape of the ejecta shows that this is not a uniform global eruption. Instead, it is coming from one or more discrete sources on the comet's surface.

This fits a leading model of the comet developed by Dr. Richard Miles of the British Astronomical Association. Miles believes that 29P is festooned with ice volcanoes. There is no lava. The "magma" is a cold mixture of liquid hydrocarbons (e.g., CH4, C2H4, C2H6 and C3H8) akin to those found in lakes and streams on Saturn's moon Titan. The cryomagma is suffused with dissolved gases N2 and CO, much like carbonation in a soda bottle. These bottled-up volatiles love to explode when a fissure is opened by the warming action of sunlight.

A new image just taken by Cai Stoddard-Jones using the Faulkes Telescope North adds weight to the idea that a single volcano or active zone is involved. Processing the data with a rotational gradient filter, Stoddard-Jones found an intense condensation of debris at position angle 330 degrees:
comet 29P/Schwassmann-Wachmann
This narrow plume probably leads back to the primary source the eruption. The plume is currently streaming away from the nucleus at 75 m/s (270 km/hr) and stretches more than 11,000 km from end to end. If an eruption like this were happening on Earth, it would jut far outside our planet's atmosphere; it's huge.

These dimensions, plus the integrated brightness of the comet (magnitude +11), put 29P within easy range of many backyard telescopes. If past eruptions are any guide, Pac-Man should grow much larger in the nights ahead. Observers can find 29P after sunset in the constellation Gemini.
comet 29P/Schwassmann-Wachmann
For more information visit the British Astronomical Association's MISSION 29P website.