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Daniel Thorngren - One of the best experts on this subject based on the ideXlab platform.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    Astronomy and Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    Aims: We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5 μm. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. Augmenting our sample with 16 previously published exoplanets leads to a total of 49. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0-1012 cm2 s-1) as well as two chemical compositions (1x and 30x solar). Results: We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5 μm, which is measured at 7.5σ level of significance. Changes in the opacities in the two Spitzer bandpasses are expected with increasing Temperature due to the transition from methane-dominated to carbon-monoxide-dominated atmospheres at chemical equilibrium. Comparing the data with our model grids, we find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3σ confidence while supporting low vertical mixing (Kzz = 108 cm2 s-1). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 1012 cm2 s-1). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-Temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission in the same bandpasses for the same planets and find no evidence for any correlation. Although more advanced modelling would test our conclusions further, our simple generic model grid points towards different amounts of vertical mixing occurring across the Temperature range of hot Jupiters. This finding also agrees with the observed scatter with increasing Planetary magnitude seen in Spitzer/IRAC color-magnitude diagrams for planets and brown dwarfs.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    arXiv: Earth and Planetary Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    [Abridged] Aims. We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5um. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0 - 10^12 cm2/s) as well as two chemical compositions (1x and 30x solar). Results. We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5um, which is measured at 7.5sigma level of significance. We find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3sigma confidence while supporting low vertical mixing (Kzz = 10^8 cm2/s). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 10^12 cm2/s). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission for the same planets and find no evidence for correlation.

Mercedes Lopez-morales - One of the best experts on this subject based on the ideXlab platform.

  • A UNIFORM SEARCH FOR SECONDARY ECLIPSES OF HOT JUPITERS IN KEPLER Q2 LIGHT CURVES
    The Astronomical Journal, 2012
    Co-Authors: Jeffrey L. Coughlin, Mercedes Lopez-morales
    Abstract:

    In this paper, we present the results of searching the Kepler Q2 public data set for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1235 candidates published by Borucki et al. This search has been performed by modeling both the Kepler pre-search data conditioned light curves and new light curves produced via our own photometric pipeline. We derive new stellar and Planetary parameters for each system, while calculating robust errors for both. We find 16 systems with 1{sigma}-2{sigma}, 14 systems with 2{sigma}-3{sigma}, and 6 systems with >3{sigma} confidence level secondary eclipse detections in at least one light curve produced via the Kepler pre-search data conditioned light curve or our own pipeline; however, results can vary depending on the light curve modeled and whether eccentricity is allowed to vary or not. We estimate false alarm probabilities of 31%, 10%, and 6% for the 1{sigma}-2{sigma}, 2{sigma}-3{sigma}, and >3{sigma} confidence intervals, respectively. Comparing each secondary eclipse result to theoretical expectations, we find that the majority of detected planet candidates emit more light than expected owing to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective Planetary Temperature.more » These results agree with previously published optical secondary eclipse data for other hot Jupiters. We explore modeling biases, significant Planetary albedos, non-local thermodynamic equilibrium or other thermal emission, significant internal energy generation, and misidentification of brown dwarfs, low-mass stars, or stellar blends as possible causes of both the excess emission and its correlation with expected Planetary Temperature. Although we find that no single cause is able to explain all of the planet candidates, significant Planetary albedos, with a general trend of increasing Planetary albedos with decreasing atmospheric Temperatures, are able to explain most of the systems. Identifying systems that we deem likely to be low-mass stars or stellar blends, we estimate an 11% false-positive rate in the current Kepler planet candidate sample of hot Jupiters. We also establish robust upper limits on the eclipse depth for the remaining systems and find that the emission of a significant fraction of these systems is consistent with the planets having very low albedos, i.e., at least 30% of all systems have A{sub g} < 0.3 at 1{sigma} confidence levels. This result augments the current number of constrained exoPlanetary albedos and extends the sample of low albedo determinations to planets with Temperatures as low as 1200 K. Finally, we note that continued observations with the Kepler spacecraft and improved techniques for the removal of systematic noise in the Kepler data are needed to better characterize these systems.« less

Jeffrey L. Coughlin - One of the best experts on this subject based on the ideXlab platform.

  • A UNIFORM SEARCH FOR SECONDARY ECLIPSES OF HOT JUPITERS IN KEPLER Q2 LIGHT CURVES
    The Astronomical Journal, 2012
    Co-Authors: Jeffrey L. Coughlin, Mercedes Lopez-morales
    Abstract:

    In this paper, we present the results of searching the Kepler Q2 public data set for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1235 candidates published by Borucki et al. This search has been performed by modeling both the Kepler pre-search data conditioned light curves and new light curves produced via our own photometric pipeline. We derive new stellar and Planetary parameters for each system, while calculating robust errors for both. We find 16 systems with 1{sigma}-2{sigma}, 14 systems with 2{sigma}-3{sigma}, and 6 systems with >3{sigma} confidence level secondary eclipse detections in at least one light curve produced via the Kepler pre-search data conditioned light curve or our own pipeline; however, results can vary depending on the light curve modeled and whether eccentricity is allowed to vary or not. We estimate false alarm probabilities of 31%, 10%, and 6% for the 1{sigma}-2{sigma}, 2{sigma}-3{sigma}, and >3{sigma} confidence intervals, respectively. Comparing each secondary eclipse result to theoretical expectations, we find that the majority of detected planet candidates emit more light than expected owing to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective Planetary Temperature.more » These results agree with previously published optical secondary eclipse data for other hot Jupiters. We explore modeling biases, significant Planetary albedos, non-local thermodynamic equilibrium or other thermal emission, significant internal energy generation, and misidentification of brown dwarfs, low-mass stars, or stellar blends as possible causes of both the excess emission and its correlation with expected Planetary Temperature. Although we find that no single cause is able to explain all of the planet candidates, significant Planetary albedos, with a general trend of increasing Planetary albedos with decreasing atmospheric Temperatures, are able to explain most of the systems. Identifying systems that we deem likely to be low-mass stars or stellar blends, we estimate an 11% false-positive rate in the current Kepler planet candidate sample of hot Jupiters. We also establish robust upper limits on the eclipse depth for the remaining systems and find that the emission of a significant fraction of these systems is consistent with the planets having very low albedos, i.e., at least 30% of all systems have A{sub g} < 0.3 at 1{sigma} confidence levels. This result augments the current number of constrained exoPlanetary albedos and extends the sample of low albedo determinations to planets with Temperatures as low as 1200 K. Finally, we note that continued observations with the Kepler spacecraft and improved techniques for the removal of systematic noise in the Kepler data are needed to better characterize these systems.« less

  • a uniform search for secondary eclipses of hot jupiters in kepler q2 lightcurves
    arXiv: Solar and Stellar Astrophysics, 2011
    Co-Authors: Jeffrey L. Coughlin, Mercedes Lopezmorales
    Abstract:

    We present the results of searching the Kepler Q2 public dataset for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1,235 candidates published by Borucki et al. (2011). This search has been performed by modeling both the Kepler PDC light curves and new light curves produced via our own photometric pipeline. We derive new stellar and Planetary parameters for each system with robust errors. We find 16 systems with 1-2 sigma, 14 systems with 2-3 sigma, and 6 systems with >3 sigma confidence level secondary eclipse detections in at least one light curve. We find that the majority of detected planet candidates emit more light than expected due to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective Planetary Temperature. We explore modeling biases, significant Planetary albedos, non-LTE or other thermal emission, significant internal energy generation, and exoplanet mis-identification as possible causes of both the excess emission and its correlation with expected Planetary Temperature. Although we find no single cause is able to explain all of the planet candidates, significant Planetary albedos, with a general trend of increasing Planetary albedos with decreasing atmospheric Temperatures, is able to explain most of the systems. We estimate an 11% false positive rate in the current Kepler planet candidate sample of hot Jupiters. We also establish robust upper limits on the eclipse depth for all systems, and find that a significant fraction of these systems have very low albedos, significantly augmenting and extending the sample of albedo determinations to planets as cool as 1200 K. Finally, we note that continued observations with Kepler, and improved techniques for the removal of systematic noise in the Kepler data, are needed to better characterize these systems.

Claire Baxter - One of the best experts on this subject based on the ideXlab platform.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    Astronomy and Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    Aims: We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5 μm. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. Augmenting our sample with 16 previously published exoplanets leads to a total of 49. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0-1012 cm2 s-1) as well as two chemical compositions (1x and 30x solar). Results: We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5 μm, which is measured at 7.5σ level of significance. Changes in the opacities in the two Spitzer bandpasses are expected with increasing Temperature due to the transition from methane-dominated to carbon-monoxide-dominated atmospheres at chemical equilibrium. Comparing the data with our model grids, we find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3σ confidence while supporting low vertical mixing (Kzz = 108 cm2 s-1). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 1012 cm2 s-1). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-Temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission in the same bandpasses for the same planets and find no evidence for any correlation. Although more advanced modelling would test our conclusions further, our simple generic model grid points towards different amounts of vertical mixing occurring across the Temperature range of hot Jupiters. This finding also agrees with the observed scatter with increasing Planetary magnitude seen in Spitzer/IRAC color-magnitude diagrams for planets and brown dwarfs.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    arXiv: Earth and Planetary Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    [Abridged] Aims. We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5um. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0 - 10^12 cm2/s) as well as two chemical compositions (1x and 30x solar). Results. We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5um, which is measured at 7.5sigma level of significance. We find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3sigma confidence while supporting low vertical mixing (Kzz = 10^8 cm2/s). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 10^12 cm2/s). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission for the same planets and find no evidence for correlation.

Sm Tsai - One of the best experts on this subject based on the ideXlab platform.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    Astronomy and Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    Aims: We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5 μm. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. Augmenting our sample with 16 previously published exoplanets leads to a total of 49. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0-1012 cm2 s-1) as well as two chemical compositions (1x and 30x solar). Results: We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5 μm, which is measured at 7.5σ level of significance. Changes in the opacities in the two Spitzer bandpasses are expected with increasing Temperature due to the transition from methane-dominated to carbon-monoxide-dominated atmospheres at chemical equilibrium. Comparing the data with our model grids, we find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3σ confidence while supporting low vertical mixing (Kzz = 108 cm2 s-1). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 1012 cm2 s-1). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-Temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission in the same bandpasses for the same planets and find no evidence for any correlation. Although more advanced modelling would test our conclusions further, our simple generic model grid points towards different amounts of vertical mixing occurring across the Temperature range of hot Jupiters. This finding also agrees with the observed scatter with increasing Planetary magnitude seen in Spitzer/IRAC color-magnitude diagrams for planets and brown dwarfs.

  • evidence for disequilibrium chemistry from vertical mixing in hot jupiter atmospheres a comprehensive survey of transiting close in gas giant exoplanets with warm spitzer irac
    arXiv: Earth and Planetary Astrophysics, 2021
    Co-Authors: Claire Baxter, Jeanmichel Desert, Sm Tsai, Kamen O Todorov, Jacob L Bean, Drake Deming, Vivien Parmentier, Jonathan J Fortney, Michael R Line, Daniel Thorngren
    Abstract:

    [Abridged] Aims. We present a large atmospheric study of 49 gas giant exoplanets using infrared transmission photometry with Spitzer/IRAC at 3.6 and 4.5um. Methods. We uniformly analyze 70 photometric light curves of 33 transiting planets using our custom pipeline, which implements pixel level decorrelation. We use this survey to understand how infrared photometry traces changes in atmospheric chemical properties as a function of Planetary Temperature. We compare our measurements to a grid of 1D radiative-convective equilibrium forward atmospheric models which include disequilibrium chemistry. We explore various strengths of vertical mixing (Kzz = 0 - 10^12 cm2/s) as well as two chemical compositions (1x and 30x solar). Results. We find that, on average, Spitzer probes a difference of 0.5 atmospheric scale heights between 3.6 and 4.5um, which is measured at 7.5sigma level of significance. We find that the coolest planets show a lack of methane compared to expectations, which has also been reported by previous studies of individual objects. We show that the sample of coolest planets rule out 1x solar composition with >3sigma confidence while supporting low vertical mixing (Kzz = 10^8 cm2/s). On the other hand, we find that the hot planets are best explained by models with 1x solar metallicity and high vertical mixing (Kzz = 10^12 cm2/s). We interpret this as the lofting of CH4 to the upper atmospheric layers. Changing the interior Temperature changes the expectation for equilibrium chemistry in deep layers, hence the expectation of disequilibrium chemistry higher up. We also find a significant scatter in the transmission signatures of the mid-temperate and ultra-hot planets, likely due to increased atmospheric diversity, without the need to invoke higher metallicities. Additionally, we compare Spitzer transmission with emission for the same planets and find no evidence for correlation.