Selected topics on extrasolar planetary systems.

摘要

This thesis investigates the capabilities of planet searches to detect extrasolar planets and measure their mass and orbital parameters. I developed and demonstrated a new technique based on Markov chain Monte Carlo simulations to quantify the uncertainty in the orbital parameters of extrasolar planets using actual radial velocity observations. It is hoped that future astrometric searches will build upon the successes of radial velocity searches, providing new information about currently known planets and discovering new ones. In particular, the Space Interferometry Mission (SIM) will be capable of detecting low-mass planets around nearby stars. I simulated astrometric observations to evaluate the planet-finding capabilities of SIM and estimate the number of planets which SIM planet searches would detect and characterize and explore how various factors would affect SIM's sensitivity. For example, I investigated the tradeoffs between observing more stars at lower precision and observing less stars at higher precision. I also determined that the choice of observing schedule has relatively little effect on SIM's efficiency, so it is likely best to schedule observations so as to minimize overhead (e.g., slewing, measuring grid stars). Similarly, I quantified how much SIM's efficiency is reduced when a target star has an acceleration due to a wide-binary companion, concluding that it is generally preferable to target a nearby star in a wide-binary system rather than a more distant single star. Finally, I explored how the presence of two planets around a star can make it more difficult for SIM to measure the masses and orbital parameters of either planet. I find that the presence a giant planet can significantly reduce the sensitivity of SIM for measuring the low-mass mass and orbital parameters of a low-mass planet. Each of these studies will help guide decisions, so that SIM's valuable observing time can be used most productively.