This review examines our current understanding of the possible birth environments of our
Solar System. Because most stars form within groups and clusters, the question becomes …

▪ Abstract Planets form in the circumstellar disks of young stars. We review the basic physical
processes by which solid bodies accrete each other and alter each others' random …

How big were the first planetesimals? We attempt to answer this question by conducting
coagulation simulations in which the planetesimals grow by mutual collisions and form …

We know little about the outermost exoplanets in planetary systems because our detection
methods are insensitive to moderate-mass planets on wide orbits. However, debris discs …

This paper presents a model for the outcome of collisions between planetesimals in a debris
disc, and assesses the impact of collisional processes on the structure and size distribution …

We describe calculations for the formation of icy planets and debris disks at 30-150 AU
around 1-3 M⊙ stars. Debris disk formation coincides with the formation of planetary …

We present new optical coronagraphic data of Fomalhaut obtained with HST/STIS in 2010
and 2012. Fomalhaut b is recovered at both epochs to high significance. The observations …

In a separate paper, we have reexamined the observations of IR excess obtained with the
Infrared Space Observatory satellite and discussed the ages of stars with excess. The …

Appetitive locomotion is essential for animals to approach rewards, such as food and prey.
The neuronal circuitry controlling appetitive locomotion is unclear. In a goal-directed …

We have investigated the spatial distribution, and the properties and chemical composition
of the dust orbiting HD 100546. This system is remarkably different from other isolated …