Comet Schwassman-Wachmann 3 is really putting on quite a show as it heads into perihelion passage by late this month. Its nucleus, which broke apart into three big chunks in 1995, has now crumbled into more than 50 pieces. Everybody seems to be tracking this thing. Spitzer Space Telescope’s image is nicely reminiscent of Shoemaker-Levy 9.
Subaru Observatory (on the Big Island of Hawai’i), has released this image of just one of the pieces, called Fragment B. It’s not the brightest of the chunks of the nucleus (that would be Fragment C), but it is showing some unusual activity.
Fragment B is itself a series of little comet nucleus shards, numbering more than 13. What does this tell us about the comet? That it most likely has a pretty delicately structured nucleus. It may also be rotating very quickly, or its ices could be vaporizing rapidly. These actions, combined with its approach to the Sun (which warms the ices even more), could be applying just the stress needed to shatter this cometary nucleus once and for all.
Of course that won’t be the end of this comet. It has been long associated with the Tau Herculid meteor shower, but this year’s recurrence of that shower probably won’t benefit from the breakup.
All of the pieces of the comet will continue to orbit the Sun in a trail of debris that is the source of the Tau Herculids. It’s a sort of diaphanous ring of dust and ice particles that have been sloughed off the comet in the past. In time, Earth could experience some heightened meteor shower activity from this breakup, but there’s good news and bad news there. The good news is that even if the shower is stronger in the future, the particles will simply collide with our atmosphere, enter it, and most likely burn up as they plow through the air.
The bad news isn’t so bad, really, just sort of disappointing: the pumped-up amount of debris in the trail of the comet won’t encounter Earth until 2022. So, it’s possible that the meteor shower probably could become quite spectacular in the future. Or not. So stay tuned.