Extrasolar planetary surveys have discovered about 780 extrasolar planets and more than 100 multiple planetary systems to date, with the largest fraction of them being confirmed by the radial velocity detection method. Multiple planetary systems, especially those contain pairs of planets in mean-motion resonances, are particularly interesting because their current orbital architectures provide constraints for orbital evolution of planetary systems. Precisely determining the orbital and dynamical state of multiple planetary systems with radial velocity measurements is important. New results from an analysis of radial velocity data of the HD 82943 planetary system based on 10 years of measurements obtained with the Keck telescope is presented in this thesis. Previous studies have shown that the HD 82943 system has two planets that are likely in 2:1 MMR, with the orbital periods about 220 and 440 days (Lee et al. 2006). However, alternative fits that are qualitatively different have also been suggested, with the two planets in 1:1 resonance or the addition of a third planet possibly in a Laplace 4:2:1 resonance with the other two (Goździewski & Konacki 2006; Beaugé et al. 2008). Here based on the X^2 minimization method combined with parameter grid search, the orbital parameters and dynamical states of the qualitatively different types of fits have been investigated. The results support the coplanar 2:1 MMR configuration for this system and fits of the 1:1 resonance and the 3-planet Laplace resonance are ruled out according to X^2 statistic and dynamical instability. The inclination of the HD 82943 system is well constrained at about 20°C. The system contains two planets with masses of about 4.64 MJ and 4.66 MJ and orbital periods of about 219 and 442 days for the inner and outer planet, respectively. The best fit is dynamically stable with two resonance angles θ 1 = λ1 - 2λ2 + ϖ1 and θ 2 = λ1 - 2λ2 + ϖ 2 librating around 0°. Based on the best fit, the origin of the 2:1 MMR of the HD 82943 planetary system has been explored by N-body simulations with forced inward migration of the outer planet. This research has demonstrated the importance of dynamical fitting for multiple planetary systems with radial velocity measurements. It also fulfills the cases of planetary systems in mean-motion resonances such that more generic understanding of the orbital evolution of planetary systems can be obtained. / published_or_final_version / Earth Sciences / Master / Master of Philosophy

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Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph.D.) - University of St Andrews, May 2007.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (p. 85-89).

Mean-motion resonances (MMR) are frequently observed in extrasolar planetary systems. It is generally believed that the resonances result from the convergent migration of planets. The much larger number of systems near the 2:1 resonance compared to 3:1 resonance in both the radial velocity and the Kepler data is probably due to the difference in the capture behaviors of 2:1 and 3:1 resonances. To study the capture probability of the 3:1 resonance, numerical three-body integrations with forced migration have been used to examine the dependence of the capture probability on migration rate, planetary masses, and initial orbital eccentricities. First, the numerical results have been confirmed with analytic theory in the adiabatic limit (Borderies & Goldreich 1984) and numerical results of the Hamiltonian model beyond this limit (Mustill & Wyatt 2011) for both the interior and exterior resonances in the circular restricted three-body problem. Then, the numerical exploration of the restricted three-body problem (R3BP) has been extended to cases with non-zero planet eccentricity in the adiabatic limit. The capture probability decreases with increasing planet eccentricity at small test particle eccentricity but does not depend strongly on the planet eccentricity at large test particle eccentricity. Interestingly, the critical eccentricity of the planet, below which resonance capture is certain, is much larger than the critical eccentricity of test particle which was not expected. Finally, the numerical exploration has been extended to situations with different planetary mass ratio m1/m2. In the cases where both planets are initially on circular orbits, the critical migration rate for certain capture agrees with that of Quillen (2006) in the R3BP. However, it does not change monotonically with m1/m2 and peaks at m1/m2 = 1. For m1/m2 = 1, the resonance capture is certain when the eccentricities of the inner and outer planets are small and decreases as the eccentricities increase. In contrast, the capture probability is low when the eccentricities are small and the capture probability peaks at certain values of the eccentricities in the non-adiabatic limits. The capture probability as a function of planet eccentricities for mass ratios m1/m2 = 0.5 and 2 in the adiabatic limit has also been studied. The capture probability at m1/m2 = 2 shows similar behaviors with m1/m2 = 1 but the capture behaviors at m1/m2 = 0.5 are significantly different from the capture behaviors at m1/m2 = 1. This research has explored the probability of resonant capture in several new regimes, including the elliptical restricted three-body problem, comparable mass cases in the adiabatic limit and the equal mass case in the non-adiabatic limits. This work enhances our knowledge in the capture behaviors of 3:1 MMR in different limits and is useful in the future studies of the period ratio distribution in extrasolar planet systems. / published_or_final_version / Physics / Master / Master of Philosophy

This dissertation is primarily focused on the topic of M dwarf metallicities and their relevance to the study of extrasolar planets. I begin by describing a method for accurately determining M dwarf metallicities with spectral synthesis based on abundance analyses of visual binary stars. I then apply this technique and present the first spectroscopic metallicities of three M dwarfs with planetary mass companions. The three M dwarf planet hosts have sub-solar metallicities, a surprising departure from the trend observed in FGK-type planet hosting stars. I discuss the implications of this result for extrasolar planet searches around the most numerous stars in the galaxy. I also present measured metallicities for a select group of M dwarfs with precisely determined masses and luminosities. Comparison of these stars' V band magnitudes with the predictions of the current state-of-the-art theoretical models for low-mass stars indicate that the models are deficient, as previously thought. I discuss how the cool star model atmospheres that were developed for the metallicity analysis technique might be used to improve M dwarf structure and evolution models. In addition to M dwarf metallicities, I describe some complementary work to determine the true mass of an extrasolar planet candidate using a combined analysis of high-precision astrometry and radial velocities. I present a dynamical mass for the companion to HD 33636 that indicates it is a low-mass star instead of an exoplanet. This result demonstrates the value of follow-up astrometric observations to determine the true masses of exoplanet candidates detected with the radial velocity method. Finally, I discuss the broader implications of the results presented in this dissertation and the prospect for similar work in the future. / text

We present the results of a survey of 45 young (<250>Myr), close (<50>pc) stars with the Simultaneous Differential Imager (SDI) implemented at the VLT and the MMT for the direct detection of extrasolar planets. Our SDI devices use a double Wollaston prism and a quad filter to take images simultaneously at three wavelengths surrounding the 1.62 um methane absorption bandhead found in the spectrum of cool brown dwarfs and extrasolar giant planets. By performing a difference of adaptive optics corrected images in these filters, speckle noise from the primary star can be significantly attenuated, resulting in photon (and flat-field) noise limited data. In our VLT data, we achieved H band contrasts > 10 mag (5 sigma) at a separation of 0.5" from the primary star on 45% of our targets and H band contrasts of > 9 mag at a separation of 0.5'' on 80% of our targets. With this degree of attenuation, we should be able to image (5 sigma detection) a 7 MJup planet 15 AU from a 70 Myr K1 star at 15 pc or a 7.8 MJup planet at 2 AU from a 12 Myr M star at 10 pc. Using the capabilities of the unique SDI device, we also discovered a methane-rich substellar companion to SCR 1845-6357 (a recently discovered (Hambly et al., 2004) M8.5 star just 3.85 pc from the Sun (Henry et al., 2006) at a separation of 4.5 AU (1.170''+-0.003'' on the sky) and fainter by 3.57$\pm$0.057 mag in the 1.575 um SDI filter.We also present high resolution (~0.1''), very high Strehl ratio (0.97+-0.03) mid-infrared (IR) adaptive optics (AO) images of the AGB star RV Boo utilizing the MMT adaptive secondary AO system. RV Boo was observed at a number of wavelengths over two epochs and appeared slightly extended at all wavelengths. With such high Strehls we can achieve super-resolutions of 0.1'' by deconvolving RV Boo with a point-spread function (PSF) derived from an unresolved star.SDI on ground based telescopes provides significant speckle attenuations down to star-planet contrasts of ~1-3x10^4. To test the classical SDI technique at contrasts of 10^6-9, we implemented a similar multiwavelength differential imaging scheme for the JPL High Contrast Imaging Testbed.

The transit method of detecting extrasolar planets relies on the small periodic changes in the brightness of the planet's host star as the planet orbits between the observer and the star. Transiting planets are extremely useful discoveries due to the significant gain in information that can be obtained on the planet and its host star than extrasolar planets discovered with other methods. The field of transiting planets has matured rapidly in the last 5 years, particularly in the area of wide-field surveys. This thesis describes the results of two such surveys. The Vulcan South Antarctic Planet Finder was designed to exploit the conditions at the South Pole, which are ideal for a transit survey. Several hardware failures resulted in the acquisition of only a small amount of corrupted data on a single field. The University of New South Wales Extrasolar Planet Search is an ongoing transit survey using the 0.5-m Automated Patrol Telescope at Siding Spring Observatory, Australia. 25 fields were observed for 1-4 months each between 2004 October and 2007 May. Light curves were constructed for ~87,000 stars down to I= 14th magnitude, and from these 23 planet candidates were identified. Ten candidates were eliminated using higher spatial resolution archived images and online catalogue data. Eight were followed up with higher spatial resolution imaging and/or medium resolution spectroscopy and were determined to be eclipsing binaries. Five candidates remain that require additional observation to determine their nature. No planets have been confirmed in this data set thus far. The large sets of high precision light curves generated by transit surveys hold significant potential for additional data-mining. To demonstrate this, a variable star catalogue was compiled from the full data set. A total of 850 variable stars were identified, with 659 new discoveries. In the course of compiling this catalogue, the first example of a high-amplitude δ Scuti star in an eclipsing binary was identified. This represented the first opportunity for a dynamical mass measurement of a highamplitude δ Scuti star, and the system was studied comprehensively.

The transit method of detecting extrasolar planets relies on the small periodic changes in the brightness of the planet's host star as the planet orbits between the observer and the star. Transiting planets are extremely useful discoveries due to the significant gain in information that can be obtained on the planet and its host star than extrasolar planets discovered with other methods. The field of transiting planets has matured rapidly in the last 5 years, particularly in the area of wide-field surveys. This thesis describes the results of two such surveys. The Vulcan South Antarctic Planet Finder was designed to exploit the conditions at the South Pole, which are ideal for a transit survey. Several hardware failures resulted in the acquisition of only a small amount of corrupted data on a single field. The University of New South Wales Extrasolar Planet Search is an ongoing transit survey using the 0.5-m Automated Patrol Telescope at Siding Spring Observatory, Australia. 25 fields were observed for 1-4 months each between 2004 October and 2007 May. Light curves were constructed for ~87,000 stars down to I= 14th magnitude, and from these 23 planet candidates were identified. Ten candidates were eliminated using higher spatial resolution archived images and online catalogue data. Eight were followed up with higher spatial resolution imaging and/or medium resolution spectroscopy and were determined to be eclipsing binaries. Five candidates remain that require additional observation to determine their nature. No planets have been confirmed in this data set thus far. The large sets of high precision light curves generated by transit surveys hold significant potential for additional data-mining. To demonstrate this, a variable star catalogue was compiled from the full data set. A total of 850 variable stars were identified, with 659 new discoveries. In the course of compiling this catalogue, the first example of a high-amplitude δ Scuti star in an eclipsing binary was identified. This represented the first opportunity for a dynamical mass measurement of a highamplitude δ Scuti star, and the system was studied comprehensively.