Why are extrasolar planets so hard to detect?
Deming: They’re so hard to detect because, so far, we cannot spatially resolve them from their parent stars, so we have to study them in the combined light of the planet and the star. That means it’s a small signal riding on top of a large noise source – in this case, the star. NTB: You are the principal investigator on a program called EPOCh, which stands for Extrasolar Planet Observations and Characterization. Tell us about that program and what you hop to accomplish with it. Deming: Well, we have just concluded our observing with EPOCh. We have over 170,000 images of planet-hosting stars, and when we get these images we don’t resolve the planet from the star. We use the images to do precise photometry. These are bright stars that have planets that transit in front of them, and the geometry of the transit tells us quite a bit about the planet. It tells us the radius. We can examine the data to see whether it has rings or moons. We can look for other, smaller planets in the system tha