THE UNIVERSITY OF CHICAGO GLIMPSES OF FAR AWAY PLACES: INTENSIVE ATMOSPHERE CHARACTERIZATION OF EXTRASOLAR PLANETS A DISSERTATION SUBMITTED TO THE FACULTY OF THE DIVISION OF THE PHYSICAL SCIENCES IN CANDIDACY FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF ASTRONOMY AND ASTROPHYSICS BY LAURA KREIDBERG CHICAGO, ILLINOIS AUGUST 2016 Copyright c 2016 by Laura Kreidberg All Rights Reserved Far away places with strange sounding names Far away over the sea Those far away places with strange sounding names Are calling, calling me. { Joan Whitney & Alex Kramer TABLE OF CONTENTS LIST OF FIGURES . vii LIST OF TABLES . ix ACKNOWLEDGMENTS . x ABSTRACT . xi 1 INTRODUCTION . 1 1.1 Exoplanets' Greatest Hits, 1995 - present . 1 1.2 Moving from Discovery to Characterization . 2 1.2.1 Clues from Planetary Atmospheres I: How Do Planets Form? . 2 1.2.2 Clues from Planetary Atmospheres II: What are Planets Like? . 3 1.2.3 Goals for This Work . 4 1.3 Overview of Atmosphere Characterization Techniques . 4 1.3.1 Transmission Spectroscopy . 5 1.3.2 Emission Spectroscopy . 5 1.4 Technical Breakthroughs Enabling Atmospheric Studies . 7 1.5 Chapter Summaries . 10 2 CLOUDS IN THE ATMOSPHERE OF THE SUPER-EARTH EXOPLANET GJ 1214b . 12 2.1 Introduction . 12 2.2 Observations and Data Reduction . 13 2.3 Implications for the Atmosphere . 14 2.4 Conclusions . 18 3 A PRECISE WATER ABUNDANCE MEASUREMENT FOR THE HOT JUPITER WASP-43b . 21 3.1 Introduction . 21 3.2 Observations and Data Reduction . 23 3.3 Analysis . 24 3.4 Results . 27 3.4.1 Constraints from the Emission Spectrum . 27 3.4.2 Constraints from the Transmission Spectrum . 29 3.4.3 Joint Constraint on the Water Abundance . 30 3.5 Discussion . 30 3.5.1 Comparison with Solar System Planets . 30 3.5.2 Prospects for Future Work . 33 iv 4 A DETECTION OF WATER IN THE TRANSMISSION SPECTRUM OF THE HOT JUPITER WASP-12b AND IMPLICATIONS FOR ITS ATMOSPHERIC COMPO- SITION . 35 4.1 Introduction . 36 4.2 Observations and Data Reduction . 38 4.2.1 Observations . 38 4.2.2 Data Reduction . 42 4.3 Light Curve Fits . 44 4.3.1 Broadband Light Curves . 44 4.3.2 Spectroscopic Light Curves . 46 4.3.3 Correction of Dilution from Stellar Companions . 49 4.4 Comparison with Previous Results . 50 4.5 Retrieval of the Atmospheric Properties . 53 4.5.1 FREE Retrieval with CHIMERA . 54 4.5.2 CHEMICALLY-CONSISTENT Retrieval with CHIMERA . 58 4.5.3 Retrieval with NEMESIS . 61 4.6 Implications for Atmospheric C/O . 62 4.6.1 Constraints from the FREE Retrieval . 62 4.6.2 Constraints from the C-C Retrieval . 63 4.7 Summary & Conclusions . 64 5 BATMAN: BASIC TRANSIT MODEL CALCULATION IN PYTHON . 78 5.1 Introduction . 78 5.2 Algorithm . 80 5.3 The batman package . 82 5.3.1 Limb Darkening Models . 82 5.3.2 Secondary Eclipse Model . 84 5.3.3 Utilities . 84 5.3.4 Accuracy . 85 5.3.5 Performance . 86 5.3.6 Comparison with Analytic Models for Nonlinear Limb Darkening . 89 5.4 Summary . 89 6 A SPECTROSCOPIC PHASE CURVE FOR THE HOT JUPITER WASP-103b . 91 6.1 Introduction . 91 6.2 Observations and Data Reduction . 92 6.2.1 HST /WFC3 . 93 6.2.2 Spitzer/IRAC . 94 6.2.3 Spitzer/IRAC . 96 6.3 Preliminary Results . 99 6.4 Future Work . 100 v 7 CONCLUSIONS & FUTURE PROSPECTS . 104 7.1 Conclusions . 104 7.2 Near Future Prospects . 106 7.3 Far Future Prospects . 108 A SUPPLEMENTARY INFORMATION FOR GJ 1214b RESULTS . 110 A.1 Observations . 110 A.2 Data reduction . 112 A.3 Systematics correction . 114 A.4 Light curve fits . 115 REFERENCES . 122 vi LIST OF FIGURES 1.1 Transmission Spectroscopy Schematic . 6 1.2 Thermal Emission Schematic . 8 2.1 Spectrophotometric Data for Transit Observations of GJ 1214b . 15 2.2 The Transmission Spectrum of GJ 1214b . 16 2.3 Spectral Retrieval Results for a Two-Component (H/He and Water) Model At- mosphere for GJ 1214b . 19 3.1 Emission and Transmission Spectra for WASP-43b . 26 3.2 Pairs Plots of Retrieved Parameters . 28 3.3 Water Abundance of WASP-43b . 31 3.4 Atmospheric Metallicity Versus Planet Mass . 34 4.1 Raw HST/WFC3 Images for WASP-12b . 39 4.2 Photometric Monitoring . 41 4.3 Example Spectra . 43 4.4 Spectroscopic Light Curve Fit . 47 4.5 Pairs Plot for MCMC Fit to Light Curve . 68 4.6 Trends in Systematics Decorrelation Parameters with Detector Illumination . 69 4.7 Dilution from Companion Star . 70 4.8 WASP-12b Transmission Spectrum . 71 4.9 Comparison with Previous Transmission Spectra Measurements . 72 4.10 Best Fit Models from Spectral Retrieval . 73 4.11 Pairs Plot for Retrieved Atmospheric Parameters . 74 4.12 Constraints on C/O, Metallicity, and Thermal Profile . 75 4.13 Retrieved Water Abundance Compared to Chemical Equilibrium Predictions . 76 4.14 Pressure Levels Sensed by the Transmission Spectrum . 77 5.1 Schematic Illustration of Integration Scheme . 83 5.2 Example Transit Light Curve and Truncation Error . 87 5.3 Performance for Numeric Integration Versus Analytic Model . 88 6.1 Band-Integrated WFC3 Phase Curve for WASP-103b . 95 6.2 Spitzer Phase Curves for WASP-103b . 97 6.3 WASP-103b Companion . 98 6.4 Phase Resolved Emission Spectra for WASP-103b . 102 6.5 WASP-103b Dayside Emission Spectrum . 103 7.1 The Road to Earth 2.0 . 107 A.1 A Sample Raw Data Frame . 111 A.2 GJ 1214b Extracted Spectrum . 113 A.3 White Light Curve, Raw and Systematics-Corrected ..