Observational constraints on the steady-state catastrophic disruption rate of main belt asteroids measured using the Pan-STARRS moving object processing system

• Main Author: Denneau, Larry
• Published: Queen's University Belfast 2015
• Subjects: 521
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680156

I present the results of a search for main belt catastrophic disruptions over a 453-day Interval in the Pan-STARRS1 survey. I describe the design and Implementation of the Pan-STARRS Moving Object Processing System (MOPS), a software environment capable of both a) detecting moving objects in the Pan-STARRS1 transient detection stream and b) characterizing a general survey telescope's efficiency at detecting moving objects, providing a statistical framework from which one can characterize entire populations. I devised a simple model to describe how a catastrophic disruption would appear to the Pan-STARRS1 detection system, constructed simulations containing 1 billion synthetic catastrophic disruptions and used MOPS to measure the efficacy of Pan-STARRS1 to detect catastrophic disruption events. The catastrophic disruption search identifies a candidate catastrophic disruption, named P1 01 Oae, whose apparent brightness V = 18.5 is used to set an upper limit to the rate at which catastrophic disruptions can occur in the main asteroid belt. I adopt the power-law formulation from Bottke et al. (2005) describing differential disruption rates as a function of diameter to compute the largest diameter (more precisely the absolute magnitude HCL) at which one disruption can be occurring per year. The computed HCL suggests that collisional catastrophic disruptions, which are predicted to exhibit brightness Increases of 20 magnitudes, are occurring once per year for objects with H - 2B.7 (about 7 m diameter). At face value this would mean that for 100 m asteroids, collisional catastrophic disruptions are occurring at - 1/500 the rate predicted by Bottke et al. (2005). Recent work by Jacobson et al. (2014) shows that disruption by rotational spin-up from the Yarkovsky-O'Keefe- Radzievskii-Paddock effect (YORP; Rubincam 2000) may occur - 400 times more frequently than colllslonal disruptions, effectively making up the deficit In catastrophically disrupted 100 m asteroids.