The Experts below are selected from a list of 82440 Experts worldwide ranked by ideXlab platform
Adam P Showman - One of the best experts on this subject based on the ideXlab platform.
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the effect of 3d transport induced disequilibrium carbon chemistry on the Atmospheric Structure phase curves and emission spectra of hot jupiter hd 189733b
The Astrophysical Journal, 2019Co-Authors: Maria E Steinrueck, Adam P Showman, Vivien Parmentier, Joshua D Lothringer, R LupuAbstract:NASA Origins grant [NNX12AI79G]; NASA Headquarters under the NASA Earth and Space Science Fellowship Program [80NSSC18K1248]; Heising-Simons Foundation
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the effect of 3d transport induced disequilibrium carbon chemistry on the Atmospheric Structure and phase curves and emission spectra of hot jupiter hd 189733b
Unknown Journal, 2018Co-Authors: Maria E Steinrueck, Adam P Showman, Vivien Parmentier, Joshua D Lothringer, R LupuAbstract:On hot Jupiter exoplanets, strong horizontal and vertical winds should homogenize the abundances of the important absorbers CH$_4$ and CO much faster than chemical reactions restore chemical equilibrium. This effect, typically neglected in general circulation models (GCMs), has been suggested as explanation for discrepancies between observed infrared lightcurves and those predicted by GCMs: On the nightsides of several hot Jupiters, GCMs predict outgoing fluxes that are too large, especially in the Spitzer 4.5 $\mu$m band. We modified the SPARC/MITgcm to include disequilibrium abundances of CH$_4$, CO and H$_2$O by assuming that the CH$_4$/CO ratio is constant throughout the simulation domain. We ran simulations of hot Jupiter HD 189733b with 8 CH$_4$/CO ratios. In the more likely CO-dominated regime, we find temperature changes $\geq$50-100 K compared to the equilibrium chemistry case across large regions. This effect is large enough to affect predicted emission spectra and should thus be included in GCMs of hot Jupiters with equilibrium temperatures between 600K and 1300K. We find that spectra in regions with strong methane absorption, including the Spitzer 3.6 and 8 $\mu$m bands, are strongly impacted by disequilibrium abundances. We expect chemical quenching to result in much larger nightside fluxes in the 3.6 $\mu$m band, in stark contrast to observations. Meanwhile, we find almost no effect on predicted observations in the 4.5 $\mu$m band, as the opacity changes due to CO and H$_2$O offset each other. We thus conclude that disequilibrium carbon chemistry cannot explain the observed low nightside fluxes in the 4.5 $\mu$m band.
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
The Astrophysical Journal, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889 431026 over the wavelength ranges 1.1 1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets. Subject headings: brown dwarfs — stars: atmospheres — stars: individual (2MASSJ22282889 4310262) — stars: variables: general
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889-431026 over the wavelength ranges 1.1-1.7 microns and broadband 4.5 microns. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets.
Neill I Reid - One of the best experts on this subject based on the ideXlab platform.
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
The Astrophysical Journal, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889 431026 over the wavelength ranges 1.1 1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets. Subject headings: brown dwarfs — stars: atmospheres — stars: individual (2MASSJ22282889 4310262) — stars: variables: general
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889-431026 over the wavelength ranges 1.1-1.7 microns and broadband 4.5 microns. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets.
Nikole K Lewis - One of the best experts on this subject based on the ideXlab platform.
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
The Astrophysical Journal, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889 431026 over the wavelength ranges 1.1 1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets. Subject headings: brown dwarfs — stars: atmospheres — stars: individual (2MASSJ22282889 4310262) — stars: variables: general
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889-431026 over the wavelength ranges 1.1-1.7 microns and broadband 4.5 microns. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets.
R Lupu - One of the best experts on this subject based on the ideXlab platform.
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the effect of 3d transport induced disequilibrium carbon chemistry on the Atmospheric Structure phase curves and emission spectra of hot jupiter hd 189733b
The Astrophysical Journal, 2019Co-Authors: Maria E Steinrueck, Adam P Showman, Vivien Parmentier, Joshua D Lothringer, R LupuAbstract:NASA Origins grant [NNX12AI79G]; NASA Headquarters under the NASA Earth and Space Science Fellowship Program [80NSSC18K1248]; Heising-Simons Foundation
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the effect of 3d transport induced disequilibrium carbon chemistry on the Atmospheric Structure and phase curves and emission spectra of hot jupiter hd 189733b
Unknown Journal, 2018Co-Authors: Maria E Steinrueck, Adam P Showman, Vivien Parmentier, Joshua D Lothringer, R LupuAbstract:On hot Jupiter exoplanets, strong horizontal and vertical winds should homogenize the abundances of the important absorbers CH$_4$ and CO much faster than chemical reactions restore chemical equilibrium. This effect, typically neglected in general circulation models (GCMs), has been suggested as explanation for discrepancies between observed infrared lightcurves and those predicted by GCMs: On the nightsides of several hot Jupiters, GCMs predict outgoing fluxes that are too large, especially in the Spitzer 4.5 $\mu$m band. We modified the SPARC/MITgcm to include disequilibrium abundances of CH$_4$, CO and H$_2$O by assuming that the CH$_4$/CO ratio is constant throughout the simulation domain. We ran simulations of hot Jupiter HD 189733b with 8 CH$_4$/CO ratios. In the more likely CO-dominated regime, we find temperature changes $\geq$50-100 K compared to the equilibrium chemistry case across large regions. This effect is large enough to affect predicted emission spectra and should thus be included in GCMs of hot Jupiters with equilibrium temperatures between 600K and 1300K. We find that spectra in regions with strong methane absorption, including the Spitzer 3.6 and 8 $\mu$m bands, are strongly impacted by disequilibrium abundances. We expect chemical quenching to result in much larger nightside fluxes in the 3.6 $\mu$m band, in stark contrast to observations. Meanwhile, we find almost no effect on predicted observations in the 4.5 $\mu$m band, as the opacity changes due to CO and H$_2$O offset each other. We thus conclude that disequilibrium carbon chemistry cannot explain the observed low nightside fluxes in the 4.5 $\mu$m band.
Esther Buenzli - One of the best experts on this subject based on the ideXlab platform.
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
The Astrophysical Journal, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889 431026 over the wavelength ranges 1.1 1.7 µm and broadband 4.5 µm. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets. Subject headings: brown dwarfs — stars: atmospheres — stars: individual (2MASSJ22282889 4310262) — stars: variables: general
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vertical Atmospheric Structure in a variable brown dwarf pressure dependent phase shifts in simultaneous hubble space telescope spitzer light curves
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: Esther Buenzli, Adam P Showman, Daniel Apai, Caroline V Morley, Davin Flateau, Adam Burrows, Mark S Marley, Nikole K Lewis, Neill I ReidAbstract:Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability in the observed flux. We report time-resolved simultaneous observations of the variable T6.5 brown dwarf 2MASSJ22282889-431026 over the wavelength ranges 1.1-1.7 microns and broadband 4.5 microns. Spectroscopic observations were taken with Wide Field Camera 3 on board the Hubble Space Telescope and photometry with the Spitzer Space Telescope. The object shows sinusoidal infrared variability with a period of 1.4 hr at most wavelengths with peak-to-peak amplitudes between 1.45% and 5.3% of the mean flux. While the light curve shapes are similar at all wavelengths, their phases differ from wavelength to wavelength with a maximum difference of more than half of a rotational period. We compare the spectra with Atmospheric models of different cloud prescriptions, from which we determine the pressure levels probed at different wavelengths. We find that the phase lag increases with decreasing pressure level, or higher altitude. We discuss a number of plausible scenarios that could cause this trend of light curve phase with probed pressure level. These observations are the first to probe heterogeneity in an ultracool atmosphere in both horizontal and vertical directions, and thus are an ideal test case for realistic three dimensional simulations of the Atmospheric Structure with clouds in brown dwarfs and extrasolar planets.