Planet hunting in new stellar domains

I have investigated the relationship between the characteristics of stars, and the occurrence and orbital properties of their planetary companions. I explored these relationships by searching for planets around extremely low-mass M Dwarfs, high-mass subgiants, and metal-rich, main-sequence stars. Several recent studies have shown that stellar metallicity is a strong tracer for planet occurrence. I worked with the "Next 2000 Stars" (N2K) Consortium to use a quick-look observing strategy to search for short-period "hot Jupiters" around nearby metal-rich stars. For this project, I developed a modification to the iodine cell Doppler technique that eliminates the need for an observed stellar template spectrum, and I used this technique to detect three new hot Jupiters. Theoretical work in the context of the core accretion planet formation model has predicted that stellar mass is another tracer of planet occurrence. I tested this prediction by searching for Jovian planets orbiting low-mass, M dwarf stars as part of the NASA Keck M Dwarfs Survey. I present the detection of only the second Jupiter-mass planetary companion orbiting an M dwarf, GL 849. I also study the relationship between stellar mass and planet occurrence by comparing the fraction of low-mass stars with planets to the corresponding fraction of Sun-like stars with planets. In addition to searching for planets around low-mass stars, I probed the high-mass end of the stellar mass distribution by searching for giant planets orbiting intermediate-mass subgiant stars. I present the detection of a rare, eccentric hot Jupiter orbiting the 1.28 M⊙ subgiant HD 185269, and 3 new exoplanets orbiting "retired" (evolved) A-type stars. I use these detections to explore the relationship between the occurrence and properties of giant planets, and the mass of their host stars.