OUTBURST DUST PRODUCTION OF COMET 29P/SCHWASSMANN-WACHMANN 1

Abstract

Multi-aperture photometry of Comet 29P/Schwassmann-Wachmann 1 was conducted on Johnson-Cousins R-band observations spanning 2011 May 1-9 and 2012 June 6-July 3. The comet was observed in outburst on 2011 May 3 and 2012 July 1, during which its brightness increased by 2.2 and 2.1 mag, respectively, as measured through a 10 arcsec aperture. Dust production before and after each outburst is calculated using the parameter Af ρ, which is converted to a lower limit on the dust production rate based on dust models and derived nuclear properties from other studies. Both outbursts are accompanied by large increases in dust production, Af ρ by a factor of ~6.5-7 and dust production rate by a factor of ~18-23. In addition, variations in the dust brightness profile of the coma are examined during the events. The profile is observed to steepen significantly at the beginning of each outburst and then slowly return to pre-outburst values, mirroring the behavior of Af ρ. The start of an outbound ripple of dust in the profile might be observed as the comet returns to its pre-outburst state, although this cannot be confirmed. Using a simple model of the 2011 May 3 outburst, an estimated lower limit of (2.6 ± 0.7) × 108 kg of dust was released during the event. If this is representative of a typical outburst of 29P, then it is estimated that outbursts account for a lower limit of 80 of the total material ejected by the comet per year.