Thesis (M.Sc.). / Written for the Dept. of Physics. Title from title page of PDF (viewed 2008/12/04). Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Georgia State University, 2007. / Title from file title page. Harold A. McAlister, committee chair; Todd J. Henry, Douglas R. Gies, Theo A. ten Brummelaar, Nikolaus Dietz, committee members. Electronic text ( 433 p. : ill.) : digital, PDF file. Description based on contents viewed Oct. 29, 2007. Includes bibliographical references (p. 184-194).

The technique of searching for extra-solar planetary transits is investigated. This technique, which relies on detecting the brief, shallow eclipses caused by planets passing across the line of sight to the primary star, requires high-precision time-series photometry of large numbers of stars in order to detect these statistically rare events. Observations of ~ 18000 stars in the field including the intermediate-age open cluster NGC 6819 are presented. This target field contrasts with the stellar environment surveyed by the radial velocity technique, which concentrates on the Solar neighbourhood. I present the data-reduction techniques used to obtain high-precision photometry in a semi-automated fashion for tens of thousands of stars at a time, together with an algorithm designed to search the resulting lightcurves for the transit signatures of hot Jupiter type planets. I describe simulations designed to test the detection efficiency of this algorithm and, for comparison, predict the number of transits expected from this data, assuming that hot Jupiter planets similar to HD 209458 are as common in the field of NGC 6819 as they are in the Solar neighbourhood. While no planetary transits have yet been identified, the detection of several very low amplitude eclipses by stellar companions demonstrates the effectiveness of the method. This study also indicates that stellar activity and particularly blending are significant causes of false detections. A useful additional consequence of studying this time-series photometry is the census it provides of some of the variable stars in the field. I report on the discovery of a variety of newly-discovered variables, including Algol-type detached eclipsing binaries which are likely to consist of M-dwarf stars. Further study of these stars is strongly recommended in order to help constrain models of stellar structure at the very low mass end. I conclude with a summary of this work in the context of other efforts being made in this field and recommend promising avenues of further study.

In this thesis I present near-infrared detections of the thermal emission of a number of hot Jupiters and likely transit depth differences from different wavelength observations of a super-Earth. I have pioneered ``Staring Mode'' using the Wide-field Infrared Camera on the Canada-France-Hawaii Telescope to achieve the most accurate photometry to-date in the near-infrared from the ground. I also discuss avenues that should allow one to achieve even more accurate photometry in the future. Using WIRCam on CFHT my collaborators and I have detected the thermal emission of the following hot Jupiters: TrES-2b and TrES-3b in Ks-band, WASP-12b in the J, H \& Ks-bands, and WASP-3b in the Ks-band on two occasions. Near-infrared detections of the thermal emission of hot Jupiters are important, because the majority of these planets' blackbodies peak in this wavelength range; near-infrared detections allow us to obtain the most model-independent constraints on these planets' atmospheric characteristics, their temperature-pressure profiles with depth and an estimate of their bolometric luminosities. With these detections we are able to answer such questions as: how efficiently these planets redistribute heat to their nightsides, if they're being inflated by tidal heating, whether there's any evidence that one of these planets is precessing, and whether another experiences extreme weather and violent storms? My collaborators and I have also observed several transits of the super-Earth GJ 1214b. We find a deeper transit depth in one of our near-infrared bands than the other. This is likely indicative of a spectral absorption feature. For the differences in the transit depth to be as large as we observed, the atmosphere of GJ 1214b must have a large scale height, low mean molecular weight and thus have a hydrogen/helium dominated atmosphere. Given that other researchers have not found similar transit depth differences, we also discuss the most likely atmospheric makeup for this planet that results from a combination of all the observations to date. Lastly, by searching for long-term linear trends in radial velocity data, I constrain the theory that most hot Jupiters migrated to their present positions via the Kozai mechanism with tidal heating.

In this thesis I present near-infrared detections of the thermal emission of a number of hot Jupiters and likely transit depth differences from different wavelength observations of a super-Earth. I have pioneered ``Staring Mode'' using the Wide-field Infrared Camera on the Canada-France-Hawaii Telescope to achieve the most accurate photometry to-date in the near-infrared from the ground. I also discuss avenues that should allow one to achieve even more accurate photometry in the future. Using WIRCam on CFHT my collaborators and I have detected the thermal emission of the following hot Jupiters: TrES-2b and TrES-3b in Ks-band, WASP-12b in the J, H \& Ks-bands, and WASP-3b in the Ks-band on two occasions. Near-infrared detections of the thermal emission of hot Jupiters are important, because the majority of these planets' blackbodies peak in this wavelength range; near-infrared detections allow us to obtain the most model-independent constraints on these planets' atmospheric characteristics, their temperature-pressure profiles with depth and an estimate of their bolometric luminosities. With these detections we are able to answer such questions as: how efficiently these planets redistribute heat to their nightsides, if they're being inflated by tidal heating, whether there's any evidence that one of these planets is precessing, and whether another experiences extreme weather and violent storms? My collaborators and I have also observed several transits of the super-Earth GJ 1214b. We find a deeper transit depth in one of our near-infrared bands than the other. This is likely indicative of a spectral absorption feature. For the differences in the transit depth to be as large as we observed, the atmosphere of GJ 1214b must have a large scale height, low mean molecular weight and thus have a hydrogen/helium dominated atmosphere. Given that other researchers have not found similar transit depth differences, we also discuss the most likely atmospheric makeup for this planet that results from a combination of all the observations to date. Lastly, by searching for long-term linear trends in radial velocity data, I constrain the theory that most hot Jupiters migrated to their present positions via the Kozai mechanism with tidal heating.

This work describes the observations and results found from a photometric survey of a 0.5° by 0.5° area of the Galactic Plane performed using the 2.2 metre ESO telescope at La Silla, Chile. The dataset comprises a total of 267 images with 204 from a 16 day observation run in 2005 and 63 from a six week observation run in 2002. The new image subtraction reduction algorithm implemented on this data resulted in more than 500,000 lightcurves with a magnitude limit of R ~ 24.5. The precision of the data following reduction is suitable for transit searches as well as identification of variable stars. Resulting from the transit search was an initial list of 31 candidates, reducing to 23 on further examination. Nine candidates were eliminated by examination of the images and the remaining list re-reduced. After this reduction three good candidates remain. These candidates have periods from 1.2840 to 2.6269 days and depths of around 75 mmags. These three candidates require followup of either multi-colour photometry or spectroscopy to determine their nature. The variable star search resulted in detections of 1475 variable stars of different types. The largest portion were eclipsing binary stars. A number of the contact binaries have possible low mass-ratios and there are also a number of contact and detached binaries which may contain low-mass components. Three of the contact binaries were found to have periods at the known period cut off including two with periods lower than any previously published. Also identified were two possible pre-main sequence detached eclipsing binaries. The binary fraction of the field was calculated from the observed contact binaries to be 46% ± 4%. There are a number of possibilities for further data mining of the survey.

This work describes the observations and results found from a photometric survey of a 0.5° by 0.5° area of the Galactic Plane performed using the 2.2 metre ESO telescope at La Silla, Chile. The dataset comprises a total of 267 images with 204 from a 16 day observation run in 2005 and 63 from a six week observation run in 2002. The new image subtraction reduction algorithm implemented on this data resulted in more than 500,000 lightcurves with a magnitude limit of R ~ 24.5. The precision of the data following reduction is suitable for transit searches as well as identification of variable stars. Resulting from the transit search was an initial list of 31 candidates, reducing to 23 on further examination. Nine candidates were eliminated by examination of the images and the remaining list re-reduced. After this reduction three good candidates remain. These candidates have periods from 1.2840 to 2.6269 days and depths of around 75 mmags. These three candidates require followup of either multi-colour photometry or spectroscopy to determine their nature. The variable star search resulted in detections of 1475 variable stars of different types. The largest portion were eclipsing binary stars. A number of the contact binaries have possible low mass-ratios and there are also a number of contact and detached binaries which may contain low-mass components. Three of the contact binaries were found to have periods at the known period cut off including two with periods lower than any previously published. Also identified were two possible pre-main sequence detached eclipsing binaries. The binary fraction of the field was calculated from the observed contact binaries to be 46% ± 4%. There are a number of possibilities for further data mining of the survey.

Thesis (Ph.D.)--Australian National University, 2005.

Thesis (Ph.D.) - University of St Andrews, June 2008.