Search for dark stars and planets by the grabitaional microlensing method

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The Japan-NZ astronomy collaboration known as MOA (Microlensing Observations in Astrophysics) installed a 1.8m telescope at Mt John in 2005. Since that time more than 500 microlensing events have been found each year towards the galactic bulge.This resulted in the discovery of 53 extra-solar planets orbiting stars in the galactic disc and the galactic bulge. These planets were found just beyond the snowlines of their host stars. This is the region of maximum sensitivity of the microlensing technique, and it also the region where ice-giant and gas-giant planets form according to the core accretion theory. The data on these planets complements data being obtained on closer-in planets by the radial velocity and transit techniques. In addition to the above discoveries, a new class of extra-solar planets was discovered by MOA. These planets are not bound to stars. They have masses similar to that of Jupiter, and they are approximately as abundant as stars in the galaxy.