29P/Schwassmann-Wachmann: A Rosetta Stone for Amorphous Water Ice and CO -> CO2 Conversion in Centaurs and Comets?
Abstract
Centaur 29P/Schwassmann-Wachmann 1 is a highly active object orbiting in the transitional "Gateway" region between the Centaur and Jupiter Family Comet regions. SW1 is unique among the Centaurs, in that it experiences quasi-regular major outbursts and produces CO emission continuously; however, the source of the CO is unclear. We argue that due to its very large size (~32 -14/+28 km radius), Centaur SW1 is likely still responding, via amorphous water ice (AWI) conversion to crystalline water ice (CWI), to the "sudden" change in its external thermal environment produced by its dynamical migration from the Kuiper belt to the Gateway Region at the inner edge of the Centaur region at 6 au. It is this conversion process that we believe is the source of the abundant CO and dust released from the object during its quiescent and outburst phases. If correct, these arguments have a number of important, testable predictions, including: the quick release on Myr timescales of CO from AWI conversion for any few km-scale scattered disk TNO transiting into the inner system; that to date SW1 has only converted between 50 to 65% of its nuclear AWI to CWI; that volume changes upon AWI conversion could have caused subsidence and cave-ins, but not significant mass wasting on SW1; that SW1's coma should contain abundant amounts of CWI CO2-rich "dust" particles; and that when SW1 transits into the inner system within the next ~1 Myr, it will be a very different kind of SP comet.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.P26A..02L