There are many ways of detecting exoplanets. Transit method is one popular technique. When a planet happens to lie between its host star and an observer, the light from the host star is partially blocked by the transiting planet. In such case, continuous monitoring the star light exhibits periodical dimming event. The signal of the event is usually very tiny, but can be sufficiently detected by a precise instrument. The Kepler satellite was launched solely for the purpose - detecting the transit signals of Earth-like planets in the habitable zone of sun-like stars. The Kepler satellite observed more than 150,000 stars over 4 years, producing enormous amount of data. While the data reduction pipeline for the Kepler mission is superb, there are some planets falling through cracks.
The Planet Hunters project takes a different approach of analyzing the Kepler data. Instead of processing the data with a pipeline, we crowd source the Kepler data to the public, relying on hundreds of thousands of eyes of citizen scientists to identify planet transit signals. Over the past 4 years, we have enlisted more than 300,000 citizen scientists, a population that is larger than 90% of the cities worldwide. With the help of Planet Hunters, we have analyzed more than 20,000,000 segmented light curves, an effort that takes a single person 200 years to achieve if working 7/24. More than 100 planet candidates have been uniquely discovered by the Planet Hunters project.
As a member on the Science Team, I am responsible for modeling light curves and taking follow-up observations for planet candidates. I have developed an algorithm to simultaneously solve for stellar properties and planet orbital properties. This algorithm is very robust especially when a planet has an eccentric orbit, which is a common case for exoplanets. Just to name a few flag ship discoveries from the project, we have discovered a circumbinary planet, a gas giant in the habitable zone, a 7-planet system, and a low-density planet that is as dense as butter.