We present spectra of Pluto’s anti-Charon hemisphere obtained from the Keck and Subaru telescopes from 2.8 to 4.2 μm. Combined with 1 2.5 μm spectra from the IRTF telescope, this collective data set lets us constrain several surface frost properties. The surface area of pure nitrogen frost (as opposed to nitrogen with dissolved methane) is constrained to be 6% or less. The ratio of pure to dilu...

We present a numerical method that incorporates particle sticking in simulations using the N-body code pkdgrav to study motions in a local rotating frame, such as a patch of a planetary ring. Particles stick to form non-deformable but breakable aggregates that obey the (Eulerian) equations of rigid-body motion. Applications include local simulations of planetary ring dynamics and planet formati...

We consider a multitype epidemic model which is a natural extension of the randomized Reed–Frost epidemic model. The main result is the derivation of an asymptotic Gaussian limit theorem for the final size of the epidemic. The method of proof is simpler, and more direct, than is used for similar results elsewhere in the epidemics literature. In particular, the results are specialized to epidemi...

We consider a multitype epidemic model which is a natural extension of the randomised Reed-Frost epidemic model. The main result is the derivation of an asympotic Gaussian limit theorem for the final size of the epidemic. The method of proof is simpler, and more direct, than is used for similar results elsewhere in the epidemics literature. In particular, the results are specialised to epidemic...