High-Contrast Near-Infrared Studies of Planetary Systems and their Circumstellar Environments

Persistent Link:
http://hdl.handle.net/10150/306772
Title:
High-Contrast Near-Infrared Studies of Planetary Systems and their Circumstellar Environments
Author:
Rodigas, Timothy John
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Planets are thought to form in circumstellar disks, leaving behind planetesimals that collide to produce dusty debris disks. Characterizing the architectures of planetary systems, along with the structures and compositions of debris disks, can therefore help answer questions about how planets form. In this thesis, I present the results of five papers (three published, two in preparation) concerning the properties of extrasolar planetary systems and their circumstellar environments. Chapters 2 and 3 are studies of radial velocity (RV) exoplanetary systems. For years astronomers have been puzzled about the large number of RV-detected planets that have eccentric orbits (e>0.1). In Chapter 2 I show that this problem can partially be explained by showing that two circular-orbit planets can masquerade as a single planet on an eccentric orbit. I use this finding to predict that planets with mildly eccentric orbits are the most likely to have massive companions on wide orbits, potentially detectable by future direct imaging observations. Chapter 3 presents such a direct imaging study of the 14 Her planetary system. I significantly constrain the phase space of the putative candidate 14 Her c and demonstrate the power of direct imaging/RV overlap. Chapters 4 and 5 are high-contrast 2-4 μm imaging studies of the edge-on debris disks around HD 15115 and HD 32297. HD 15115's color is found to be gray, implying large grains 1-10 μm in size reside in stable orbits in the disk. HD 32297's disk color is red from 1-4 μm. Cometary material (carbon, silicates, and porous water ice) are a good match at 1-2 μm but not at L'. Tholins, organic material that is found in outer solar system bodies, or small silicates can explain the disk's red color but not the short wavelength data. Chapter 6 presents a dynamical study of dust grains in the presence of massive planets. I show that the width of a debris disk increases proportionally with the mass of its shepherding planet. I then make predictions for the masses and orbits of putative planets in five well-known disks. In Chapter 7, I summarize and discuss plans for future research in the exoplanet field.
Type:
text; Electronic Dissertation
Keywords:
High-Contrast Imaging; Planetary Systems; Astronomy; Circumstellar Disks
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Astronomy
Degree Grantor:
University of Arizona
Advisor:
Hinz, Philip M.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleHigh-Contrast Near-Infrared Studies of Planetary Systems and their Circumstellar Environmentsen_US
dc.creatorRodigas, Timothy Johnen_US
dc.contributor.authorRodigas, Timothy Johnen_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractPlanets are thought to form in circumstellar disks, leaving behind planetesimals that collide to produce dusty debris disks. Characterizing the architectures of planetary systems, along with the structures and compositions of debris disks, can therefore help answer questions about how planets form. In this thesis, I present the results of five papers (three published, two in preparation) concerning the properties of extrasolar planetary systems and their circumstellar environments. Chapters 2 and 3 are studies of radial velocity (RV) exoplanetary systems. For years astronomers have been puzzled about the large number of RV-detected planets that have eccentric orbits (e>0.1). In Chapter 2 I show that this problem can partially be explained by showing that two circular-orbit planets can masquerade as a single planet on an eccentric orbit. I use this finding to predict that planets with mildly eccentric orbits are the most likely to have massive companions on wide orbits, potentially detectable by future direct imaging observations. Chapter 3 presents such a direct imaging study of the 14 Her planetary system. I significantly constrain the phase space of the putative candidate 14 Her c and demonstrate the power of direct imaging/RV overlap. Chapters 4 and 5 are high-contrast 2-4 μm imaging studies of the edge-on debris disks around HD 15115 and HD 32297. HD 15115's color is found to be gray, implying large grains 1-10 μm in size reside in stable orbits in the disk. HD 32297's disk color is red from 1-4 μm. Cometary material (carbon, silicates, and porous water ice) are a good match at 1-2 μm but not at L'. Tholins, organic material that is found in outer solar system bodies, or small silicates can explain the disk's red color but not the short wavelength data. Chapter 6 presents a dynamical study of dust grains in the presence of massive planets. I show that the width of a debris disk increases proportionally with the mass of its shepherding planet. I then make predictions for the masses and orbits of putative planets in five well-known disks. In Chapter 7, I summarize and discuss plans for future research in the exoplanet field.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectHigh-Contrast Imagingen_US
dc.subjectPlanetary Systemsen_US
dc.subjectAstronomyen_US
dc.subjectCircumstellar Disksen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHinz, Philip M.en_US
dc.contributor.committeememberHinz, Philip M.en_US
dc.contributor.committeememberClose, Lairden_US
dc.contributor.committeememberMalhotra, Renuen_US
dc.contributor.committeememberRieke, Georgeen_US
dc.contributor.committeememberApai, Danielen_US
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