BETA PICTORIS: An Early Solar System?

Abstract

▪ Abstract  Beta Pictoris (βPic) is the best studied of the normal main-sequence stars surrounded by circumstellar dust disks. We review the status of βPic and its disk, and compare it with both the early and the present Solar System. The disk has very little gas and therefore is more evolved and older than the primordial solar nebulae, which persist for 1–10 Myr. We concentrate on the observed optical properties, spatial and size distribution, mineralogy, and physics of the dust component, all of which are similar, if not identical, to those of the interplanetary and cometary dust in the Solar System. The most important process in the disk is collisional fragmentation of orbiting solid bodies, leading to the eventual removal of micron-sized and smaller debris from the system by radiation pressure. Silicate dust and sand, as well as planetesimals (perhaps comets) are observed around the star in quantities that are orders of magnitude larger than those in the present Solar System, but are consistent with a young solar system in the clearing stage. Theory of the βPic disk indicates that its age must be <100 Myr, and its mass comparable with that of all solid bodies in our system. Several indirect arguments support the hypothetical existence of planet(s) in orbit around the star. Our current knowledge strongly suggests a positive answer to the title question.