Abstract:

The recent discoveries of planetary systems in orbit around other stars have uncovered several types of planetary objects which are not represented in our own solar system. In addition to the well known 'hot-Jupiters' - gas giant planets at very short orbital distances from their parent stars - recent observations have discovered Neptune-mass objects in short-period orbits, as well as planets which appear to fall squarely into the gap between the masses of Earth and Neptune. In this paper we review the observations of these fascinating new objects, and discuss theories of their formation and speculations on their possible interior structures.

Document Type: Research article

DOI: 10.1080/00107510701521528