Eric Agol
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View article: Modeling the Solar System. I. Characterization Limits from Analytic Timing Variations
Modeling the Solar System. I. Characterization Limits from Analytic Timing Variations Open
Planetary systems with multiple transiting planets are beneficial for understanding planet occurrence rates and system architectures. Although we have yet to find a solar system (SS) analog, future surveys may detect multiple terrestrial p…
View article: First JWST thermal phase curves of temperate terrestrial exoplanets reveal no thick atmosphere around TRAPPIST-1 b and c
First JWST thermal phase curves of temperate terrestrial exoplanets reveal no thick atmosphere around TRAPPIST-1 b and c Open
We report JWST/MIRI 15 $μ$m phase curves of TRAPPIST-1 b and c, revealing thermal emission consistent with their irradiation levels, assuming no efficient heat redistribution. We find that TRAPPIST-1 b shows a high dayside brightness tempe…
View article: Updated Masses for the Gas Giants in the Eight-planet Kepler-90 System Via Transit-timing Variation and Radial Velocity Observations
Updated Masses for the Gas Giants in the Eight-planet Kepler-90 System Via Transit-timing Variation and Radial Velocity Observations Open
The eight-planet Kepler-90 system exhibits the greatest multiplicity of planets found to date. All eight planets are transiting and were discovered in photometry from the NASA Kepler primary mission. The two outermost planets, g ( P g = 21…
View article: Updated Masses for the Gas Giants in the Eight-Planet Kepler-90 System Via Transit-Timing Variation and Radial Velocity Observations
Updated Masses for the Gas Giants in the Eight-Planet Kepler-90 System Via Transit-Timing Variation and Radial Velocity Observations Open
The eight-planet Kepler-90 system exhibits the greatest multiplicity of planets found to date. All eight planets are transiting and were discovered in photometry from the NASA Kepler primary mission. The two outermost planets, g ($P_g$ = 2…
View article: A Ground-Based Transit Observation of the Long-Period Extremely Low-Density Planet HIP 41378 f
A Ground-Based Transit Observation of the Long-Period Extremely Low-Density Planet HIP 41378 f Open
We present a ground-based transit detection of HIP 41378 f, a long-period ($P = 542$ days), extremely low-density ($0.09 \pm 0.02$ g cm$^{-3}$) giant exoplanet in a dynamically complex system. Using photometry from Tierras, TRAPPIST-North,…
View article: The Exoplanet Edge: Planets Do Not Induce Observable Transit Timing Variations with a Dominant Transit Timing Variation Period Faster than Half Their Orbital Period
The Exoplanet Edge: Planets Do Not Induce Observable Transit Timing Variations with a Dominant Transit Timing Variation Period Faster than Half Their Orbital Period Open
Transit timing variations (TTVs) are observed for exoplanets at a range of amplitudes and periods, yielding an ostensibly degenerate forest of possible explanations. We offer some clarity in this forest, showing that systems with a distant…
View article: A differentiable N-body code for transit timing and dynamical modelling - II. Photodynamics
A differentiable N-body code for transit timing and dynamical modelling - II. Photodynamics Open
Exoplanet transits contain substantial information about the architecture of a system. By fitting transit light curves we can extract dynamical parameters and place constraints on the properties of the planets and their host star. Having a…
View article: Increased Surface Temperatures of Habitable White Dwarf Worlds Relative to Main-sequence Exoplanets
Increased Surface Temperatures of Habitable White Dwarf Worlds Relative to Main-sequence Exoplanets Open
Discoveries of giant planet candidates orbiting white dwarf (WD) stars and the demonstrated capabilities of the James Webb Space Telescope bring the possibility of detecting rocky planets in the habitable zones (HZs) of WDs into pertinent …
View article: A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations
A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations Open
Kepler-51 is a ≲1 Gyr old Sun-like star hosting three transiting planets with radii ≈6–9 R ⊕ and orbital periods ≈45–130 days. Transit timing variations (TTVs) measured with past Kepler and Hubble Space Telescope (HST) observations have be…
View article: The Exoplanet Edge: Planets Don't Induce Observable TTVs with a Dominant TTV Period Faster than Half their Orbital Period
The Exoplanet Edge: Planets Don't Induce Observable TTVs with a Dominant TTV Period Faster than Half their Orbital Period Open
Transit timing variations (TTVs) are observed for exoplanets at a range of amplitudes and periods, yielding an ostensibly degenerate forest of possible explanations. We offer some clarity in this forest, showing that systems with a distant…
View article: Updated Forecast for TRAPPIST-1 Times of Transit for All Seven Exoplanets Incorporating JWST Data
Updated Forecast for TRAPPIST-1 Times of Transit for All Seven Exoplanets Incorporating JWST Data Open
The TRAPPIST-1 system has been extensively observed with JWST in the near-infrared with the goal of detecting atmospheric transit transmission spectra of these temperate, Earth-sized exoplanets. A byproduct has been much more precise times…
View article: A differentiable N-body code for transit timing and dynamical modelling -- II. Photodynamics
A differentiable N-body code for transit timing and dynamical modelling -- II. Photodynamics Open
Exoplanet transits contain substantial information about the architecture of a system. By fitting transit light curves we can extract dynamical parameters and place constraints on the properties of the planets and their host star. Having a…
View article: A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations
A Fourth Planet in the Kepler-51 System Revealed by Transit Timing Variations Open
Kepler-51 is a $\lesssim 1\,\mathrm{Gyr}$-old Sun-like star hosting three transiting planets with radii $\approx 6$-$9\,R_\oplus$ and orbital periods $\approx 45$-$130\,\mathrm{days}$. Transit timing variations (TTVs) measured with past Ke…
View article: Updated forecast for TRAPPIST-1 times of transit for all seven exoplanets incorporating JWST data
Updated forecast for TRAPPIST-1 times of transit for all seven exoplanets incorporating JWST data Open
The TRAPPIST-1 system has been extensively observed with JWST in the near-infrared with the goal of measuring atmospheric transit transmission spectra of these temperate, Earth-sized exoplanets. A byproduct of these observations has been m…
View article: An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf
An Earth-Mass Planet and a Brown Dwarf in Orbit Around a White Dwarf Open
Terrestrial planets born beyond 1-3 AU have been theorized to avoid being engulfed during the red-giant phases of their host stars. Nevertheless, only a few gas-giant planets have been observed around white dwarfs (WDs) -- the end product …
View article: Modeling the Solar System as an Observed Multi-Transit System I: Characterization Limits from Analytic Timing Variations
Modeling the Solar System as an Observed Multi-Transit System I: Characterization Limits from Analytic Timing Variations Open
Planetary systems with multiple transiting planets are beneficial for understanding planet occurrence rates and system architectures. Although we have yet to find a solar system analogue, future surveys may detect multiple terrestrial plan…
View article: The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets
The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets Open
JWST observations of the seven-planet TRAPPIST-1 system will provide an excellent opportunity to test outcomes of stellar-driven evolution of terrestrial planetary atmospheres, including atmospheric escape, ocean loss, and abiotic oxygen p…
View article: The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets
The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets Open
JWST observations of the 7-planet TRAPPIST-1 system will provide an excellent opportunity to test outcomes of stellar-driven evolution of terrestrial planetary atmospheres, including atmospheric escape, ocean loss and abiotic oxygen produc…
View article: Multiple Patchy Cloud Layers in the Planetary-mass Object SIMP 0136+0933
Multiple Patchy Cloud Layers in the Planetary-mass Object SIMP 0136+0933 Open
Multiwavelength photometry of brown dwarfs and planetary-mass objects provides insight into their atmospheres and cloud layers. We present near-simultaneous J - and K s -band multiwavelength observations of the highly variable T2.5 planeta…
View article: No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c
No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c Open
Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small planets outside the Solar System. Thanks to the recent launch of the James Webb Space Telescope (JWST), possible …
View article: Multiple Patchy Cloud Layers in the Planetary Mass Object SIMP0136+0933
Multiple Patchy Cloud Layers in the Planetary Mass Object SIMP0136+0933 Open
Multi-wavelength photometry of brown dwarfs and planetary-mass objects provides insight into their atmospheres and cloud layers. We present near-simultaneous $J-$ and $K_s-$band multi-wavelength observations of the highly variable T2.5 pla…
View article: Figures for the TRAPPIST-1 JWST Community Initiative Roadmap (arXiv:2310.15895)
Figures for the TRAPPIST-1 JWST Community Initiative Roadmap (arXiv:2310.15895) Open
This upload includes the data and Jupyter notebooks necessary to reproduce the figures in the TRAPPIST-1 JWST Community Initiative Roadmap (arXiv:2310.15895).
View article: Workshop Summary: Exoplanet Orbits and Dynamics
Workshop Summary: Exoplanet Orbits and Dynamics Open
Exoplanetary systems show a wide variety of architectures, which can be explained by different formation and dynamical evolution processes. Precise orbital monitoring is mandatory to accurately constrain their orbital and dynamical paramet…
View article: Potential Atmospheric Compositions of TRAPPIST-1 c Constrained by JWST/MIRI Observations at 15 μm
Potential Atmospheric Compositions of TRAPPIST-1 c Constrained by JWST/MIRI Observations at 15 μm Open
The first James Webb Space Telescope observations of TRAPPIST-1 c showed a secondary eclipse depth of 421 ± 94 ppm at 15 μ m, which is consistent with a bare rock surface or a thin, O 2 -dominated, low-CO 2 atmosphere. Here we further expl…
View article: Potential Atmospheric Compositions of TRAPPIST-1 c constrained by JWST/MIRI Observations at 15 $μ$m
Potential Atmospheric Compositions of TRAPPIST-1 c constrained by JWST/MIRI Observations at 15 $μ$m Open
The first JWST observations of TRAPPIST-1 c showed a secondary eclipse depth of 421+/-94 ppm at 15 um, which is consistent with a bare rock surface or a thin, O2-dominated, low CO2 atmosphere (Zieba et al. 2023). Here, we further explore p…
View article: Transit analysis package: An IDL graphical user interface for exoplanet transit photometry
Transit analysis package: An IDL graphical user interface for exoplanet transit photometry Open
We present an IDL graphical user-interface-driven software package designed for the analysis of exoplanet transit light curves. The Transit Analysis Package (TAP) software uses Markov Chain Monte Carlo (MCMC) techniques to fit light curves…
View article: The Perkins INfrared Exosatellite Survey (PINES). II. Transit Candidates and Implications for Planet Occurrence around L and T Dwarfs
The Perkins INfrared Exosatellite Survey (PINES). II. Transit Candidates and Implications for Planet Occurrence around L and T Dwarfs Open
We describe a new transit-detection algorithm designed to detect single-transit events in discontinuous Perkins INfrared Exosatellite Survey (PINES) observations of L and T dwarfs. We use this algorithm to search for transits in 131 PINES …