Measurement of parallax and lens mass in the gravitational microlensing free floating planet event MOA-2011-BLG-274, and aspects of planet detection at moderately high magnification

Abstract

Microlensing is a powerful technique for detecting non-luminous objects in the galaxy. This has been one of several techniques that, in the past few years, have discovered hundreds of planets orbiting around other stars in our galaxy. The microlensing event MB11274 showed a short timescale and a large source size effect. These suggest that, rather than being a star, the lens body in this event may be a free floating planet, a class of object only recently discovered. A measurement of parallax in this event would allow the mass of this object to be measured – the first time that the mass of one of these planets has been measured directly. In this thesis an attempt to measure the terrestrial parallax signal in the event is described. Searches are also made for a nearby star, and any moons orbiting the planet. In addition, microlensing surveys looking for planets usually focus on the highest magnification events, as it is assumed that they give the best chance of detection. This thesis also presents analysis of moderate magnification microlensing events, which suggests that this type of event provides a higher sensitivity to planets.