A new histogram-free likelihood method applied to simulated JWST observations of brown dwarfs shows that globular cluster ages can be determined with formal errors under 0.2 Gyr.
C/O ratio as a Dimension for Characterizing Exoplanetary Atmospheres
7 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Until recently, infrared observations of exoplanetary atmospheres have typically been interpreted using models that assumed solar elemental abundances. With the chemical composition fixed, attempts have been made to classify hot Jupiter atmospheres on the basis of stellar irradiation. However, recent observations have revealed deviations from predictions based on such classification schemes, and chemical compositions retrieved from some datasets have also indicated non-solar abundances. In hot hydrogen-dominated atmospheres, the C/O ratio critically influences the relative concentrations of several spectroscopically dominant molecules. Between a C/O of 0.5 (solar value) and 2, the H2O and CH4 abundances can vary by several orders of magnitude in the observable atmosphere, and new hydrocarbon species such as HCN and C2H2 become prominent for C/O >= 1, while the CO abundance remains almost unchanged. Furthermore, a C/O >= 1 can preclude a strong thermal inversion due to TiO and VO in a hot Jupiter atmosphere, since TiO and VO are naturally under-abundant for C/O >= 1. We, therefore, suggest a new two-dimensional classification scheme for hydrogen-dominated exoplanetary atmospheres with irradiation (or temperature) and C/O ratio as the two dimensions. We define four classes in this 2-D space (O1, O2, C1, and C2) with distinct chemical, thermal and spectral properties. We characterize the thermal structures and C/O ratios of six hot Jupiters (XO-1b, CoRoT-2b, WASP-14b, WASP-19b, WASP-33b, and WASP-12b) in the framework of our proposed 2D classification scheme. While the data for several systems in our sample are consistent with carbon-rich atmospheres (i.e. C/O >= 1), new observations are required to conclusively constrain the C/O ratios in their atmospheres. We discuss how observations using existing and forthcoming facilities can constrain C/O ratios in exoplanetary atmospheres.
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Native-resolution retrievals on 0.97-5.27 micron JWST spectra of VHS 1256 b find a ~79% cloud deck, solar-like metallicity and C/O, and depleted 18O in a partially cloudy disequilibrium atmosphere.
JWST/MIRI survey of 2-6 Myr Upper Scorpius disks finds diverse chemotypes, 10-1000x lower water luminosities, and evidence that outer dust traps control inner-disk chemistry.
dopplerkernel parametrizes UHJ projected winds with four parameters (v_jet, sigma_jet, v_wind, phi_sink) and retrieves jet and day-to-night flows from synthetic WASP-76b K-band emission spectra generated by three GCMs.
Two extremely low-density Jupiter-sized planets on long-period orbits around TOI-791 were confirmed via ground-based photometry and TTV-derived masses.
ML regressors trained on APOGEE DR17 red giants predict C, O, Mg, Si abundances from kinematics and [Fe/H] more accurately than [Fe/H] baseline, with external validation on HARPS FGK dwarfs and reproduction of Galactic chemical evolution trends.
Observational study of 290 exoplanet-host stars finds higher C, O, S, Fe, Ni abundances in giant-planet hosts than small-planet hosts, with C/O ratios, hot/warm differences, and mass correlations that vary by subpopulation.
citing papers explorer
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New Way to Date Globular Clusters: Brown Dwarf Cooling Sequences
A new histogram-free likelihood method applied to simulated JWST observations of brown dwarfs shows that globular cluster ages can be determined with formal errors under 0.2 Gyr.
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Native-resolution retrievals of VHS 1256-1257 b spanning the JWST/NIRSpec wavelength range: Chemical composition of a partially cloudy atmosphere
Native-resolution retrievals on 0.97-5.27 micron JWST spectra of VHS 1256 b find a ~79% cloud deck, solar-like metallicity and C/O, and depleted 18O in a partially cloudy disequilibrium atmosphere.
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Chemical Divergence and Water Depletion: Gas Properties of Evolved Upper Scorpius Disks Revealed by JWST/MIRI
JWST/MIRI survey of 2-6 Myr Upper Scorpius disks finds diverse chemotypes, 10-1000x lower water luminosities, and evidence that outer dust traps control inner-disk chemistry.
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Parametrizing the projected wind fields of ultra-hot Jupiters in thermal emission: an application to GCM spectra of WASP-76b
dopplerkernel parametrizes UHJ projected winds with four parameters (v_jet, sigma_jet, v_wind, phi_sink) and retrieves jet and day-to-night flows from synthetic WASP-76b K-band emission spectra generated by three GCMs.
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ASTEP confirmation of a pair of long-period Jupiter-sized planets with extremely low densities transiting TOI-791
Two extremely low-density Jupiter-sized planets on long-period orbits around TOI-791 were confirmed via ground-based photometry and TTV-derived masses.
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Inferring stellar metallicity and elemental abundances from kinematic and spectroscopic data using machine learning -- Implications for exoplanet host stars
ML regressors trained on APOGEE DR17 red giants predict C, O, Mg, Si abundances from kinematics and [Fe/H] more accurately than [Fe/H] baseline, with external validation on HARPS FGK dwarfs and reproduction of Galactic chemical evolution trends.
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Chemical Abundances of the Bioessential Elements C, O and S, and the Refractory Elements Fe and Ni, in Solar-type Exoplanet-hosting Stars from HARPS North and South
Observational study of 290 exoplanet-host stars finds higher C, O, S, Fe, Ni abundances in giant-planet hosts than small-planet hosts, with C/O ratios, hot/warm differences, and mass correlations that vary by subpopulation.