Planets with no sun to circle are focus of study

May 19, 2011—Free-floating planets, long predicted, have finally been observed by a New Zealand/Japanese survey, NASA reports.

Apparently ejected from their home systems during planet and system formation, the lonely travelers, planets with no suns to orbit, were detected by the Microlensing Observations in Astrophysics (MOA), a NewZealand and Japanese group, and confirmed by the Optical Gravitational Lensing Experiment (OGLE) team in Chile.

The project is part of the Origins of Solar Systems program at NASA led by LANL staffer Mario Perez of the Global Security program office, who is at NASA on Intergovernmental Personnel Assignment. Perez is lead program scientist of one of the three astrophysics themes, Cosmic Origins, a portfolio that includes the largest NASA astrophysics missions, including Hubble Space Telescope, James Webb Space Telescope, Spitzer, Herschel, SOFIA, GALEX, WISE, and others. He also manages the missions and research grants related to the Cosmic Origins themes within NASA.

The orphan planet study, led by Takahiro Sumi from Osaka University in Japan, appears in the May 19 issue of the journal Nature. The survey is not sensitive to planets smaller than Jupiter and Saturn, but theories suggest lower-mass planets like Earth should be ejected from their stars more often. As a result, they are thought tobe more common than free-floating Jupiters.