Associate Professor Ian Bond PhD

Recently we found a population of 'free-floating' planets that appear not to be orbiting stars. Instead, they roam interstellar space. They could have formed in normal planetary systems and subsequently been ejected in gravitational interactions. A small population of such planets had long been anticipated, but, remarkably, our observations imply a large population, outnumbering stars by a factor of about two or more, thus implying that the process of planet formation is surprisingly chaotic. The new planets were found by a technique of Einstein in which the gravitational fields of stars are used as astronomical lenses. Previously we used this technique to study planets orbiting stars beyond their 'snowlines' where ices form. Our results complemented those obtained on warmer planets by conventional methods. The free-floating planets were discovered as gravitational lenses of weaker power than stellar lenses. The discovery measurements were sensitive to free-floating planets of about Jupiter's mass or more. In this project we shall improve the sensitivity to enable lighter free-floating planets to be detected. These may be more prevalent, and it has been conjectured that some could be habitable. We shall also extend our former studies of planets orbiting stars to include lighter planets.