New research has found planets around stars are the rule rather than the exception – there are more planets in our galaxy than there are stars. An international team including five Tasmanian astronomers made the discovery.
The team searched for exoplanets (planets outside the Solar System) using gravitational microlensing. This method can detect planets over a much wider range of masses, and distances from their parent stars (stars that give the planets light and warmth), than other methods.
In six years of observations, the Probing Lensing Anomalies NETwork (PLANET) and the Optical Gravitational Lensing Experiment (OGLE) researchers discovered three exoplanets on their own, and seven more in co-operation with other survey teams. Although the number of planets that were detected is small, statistical analysis of the microlensing process shows that it is a truly impressive haul.
To detect these planets, astronomers have either hit a jackpot against huge odds, or planets are so abundant in the galaxy that their discovery is almost inevitable.
Dr John Greenhill, School of Maths and Physics, University of Tasmania
Nature; http://www.utas.edu.au/tools/recent-news/news/planets-outnumber-stars-in-our-galaxy