Vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet

Pelletier, Stefan; Benneke, Björn; Ali-Dib, Mohamad; Prinoth, Bibiana; Kasper, David; Seifahrt, Andreas; Bean, Jacob L.; Debras, Florian; Klein, Baptiste; Bazinet, Luc; Hoeijmakers, H. Jens; Kesseli, Aurora Y.; Lim, Olivia; Carmona, Andres; Pino, Lorenzo; Casasayas-Barris, Núria; Hood, Thea; Stürmer, Julian

doi:10.1038/s41586-023-06134-0

“…There is a strong interdependence between species, common from previous observations of such targets (e.g., Line et al 2015;Burningham et al 2017;Piette & Madhusudhan 2020). This highlights that the absolute abundances of each species may not be as well constrained, but we find that their ratios are significantly more precise and robust, as also seen with ground-based high-resolution spectroscopy (Gibson et al 2022;Gandhi et al 2023;Pelletier et al 2023). The less prominent isotopologues, C 18 O and C 17 O, show the weakest correlation given their lower abundances.…”

Section: Co Isotopologuessupporting

confidence: 72%

JWST Measurements of ¹³C, ¹⁸O, and ¹⁷O in the Atmosphere of Super-Jupiter VHS 1256 b

Gandhi,

de Regt,

Snellen

et al. 2023

ApJL

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Isotope ratios have recently been measured in the atmospheres of directly imaged and transiting exoplanets from ground-based observations. The arrival of JWST allows us to characterize exoplanetary atmospheres in further detail and opens up wavelengths inaccessible from the ground. In this work we constrain the carbon and oxygen isotopes 13C, 18O, and 17O from CO in the atmosphere of the directly imaged companion VHS 1256 b through retrievals of the ∼4.1–5.3 μm NIRSpec G395H/F290LP observations from the early-release science program (ERS 1386). We detect and constrain 13C16O, 12C18O, and 12C17O at 32σ, 16σ, and 10σ confidence respectively, thanks to the very high signal-to-noise observations. We find the ratio of abundances are more precisely constrained than their absolute values, with 12 C / 13 C = 62 − 2 + 2 , in between previous measurements for companions (∼30) and isolated brown dwarfs (∼100). The oxygen isotope ratios are 16 O / 18 O = 425 − 28 + 33 and 16 O / 17 O = 1010 − 100 + 120 . All of the ratios are lower than the local interstellar medium and solar system, suggesting that abundances of the more minor isotopes are enhanced compared to the primary. This could be driven by isotope fractionation in protoplanetary disks, which can potentially alter the carbon and oxygen ratios through isotope selective photodissociation, gas/ice partitioning, and isotopic exchange reactions. In addition to CO, we constrain 1H 2 16 O and 12C16O2 (the primary isotopologues of both species), but find only upper limits on 12C1H4 and 14N1H3. This work highlights the power of JWST to constrain isotopes in exoplanet atmospheres, with great promise in determining formation histories in the future.

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“…The notable rise in opacity around 2000 K is primarily attributed to the presence of TiO/VO gases. However, current observational data does not conclusively confirm the existence of TiO/VO in the atmospheres of planets at these temperatures (e.g., Mikal-Evans et al 2022;Pelletier et al 2023). From a theoretical standpoint, the TiO/VO gases could be coldly trapped deep within the atmosphere, which could drastically alter their concentration in the photosphere (Spiegel et al 2009;Parmentier et al 2013).…”

Section: Radiative Transfer: Harpmentioning

confidence: 87%

The Inhomogeneity Effect. III. Weather Impacts on the Heat Flow of Hot Jupiters

Zhang,

Li,

Ge

et al. 2023

ApJ

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The interior flux of a giant planet impacts atmospheric motion, and the atmosphere dictates the interior’s cooling. Here we use a non-hydrostatic general circulation model (Simulating Non-hydrostatic Atmospheres on Planets) coupled with a multi-stream multi-scattering radiative module (High-performance Atmospheric Radiation Package) to simulate the weather impacts on the heat flow of hot Jupiters. We found that the vertical heat flux is primarily transported by convection in the lower atmosphere and regulated by dynamics and radiation in the overlying radiation-circulation zone. The temperature inversion occurs on the dayside and reduces the upward radiative flux. The atmospheric dynamics relay the vertical heat transport until the radiation becomes efficient in the upper atmosphere. The cooling flux increases with atmospheric drag due to increased day–night contrast and spatial inhomogeneity. The temperature dependence of the infrared opacity greatly amplifies the opacity inhomogeneity. Although atmospheric circulation could transport heat downward in a narrow region above the radiative-convective boundary, the opacity inhomogeneity effect overcomes the dynamical effect and leads to a larger overall interior cooling than the local simulations with the same interior entropy and stellar flux. The enhancement depends critically on the equilibrium temperature, drag, and atmospheric opacity. In a strong-drag atmosphere hotter than 1600 K, a significant inhomogeneity effect in three-dimensional (3D) models can boost interior cooling several-fold compared to the 1D radiative-convective equilibrium models. This study confirms the analytical argument of the inhomogeneity effect in the companion papers by Zhang. It highlights the importance of using 3D atmospheric models in understanding the inflation mechanisms of hot Jupiters and giant planet evolution in general.

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“…Following the initial processing of the raw data, we want to remove the contribution from HIP 65Ab's host star and the Earth's atmosphere to only keep the planet spectrum buried in some intrinsic noise. To do this, we closely followed the data detrending procedure described in Pelletier et al (2021Pelletier et al ( , 2023.…”

Section: Data Reduction and Telluric Removalmentioning

confidence: 99%

“…In order to detect chemical species, the data must be cross correlated with appropriate atmospheric models. Here, we use the SCARLET framework (Benneke & Seager 2012Knutson et al 2014;Kreidberg et al 2014;Benneke 2015;Benneke et al 2019bBenneke et al , 2019aPelletier et al 2021Pelletier et al , 2023 to generate models of HIP 65Ab's dayside thermal emission. SCARLET generates lineby-line high-resolution (R = 250,000) emission spectra given the temperature-pressure profile, the composition, and the cloud structure of a planet.…”

Section: Modeling and Retrieval Setupmentioning

confidence: 99%

A Subsolar Metallicity on the Ultra-short-period Planet HIP 65Ab

Bazinet,

Pelletier,

Benneke

et al. 2024

AJ

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Studying and understanding the physical and chemical processes that govern hot Jupiters gives us insights on the formation of these giant planets. Having a constraint on the molecular composition of their atmosphere can help us pinpoint their evolution timeline. Namely, the metal enrichment and carbon-to-oxygen ratio can give us information about where in the protoplanetary disk a giant planet may have accreted its envelope, and, subsequently, indicate if it went through migration. Here we present the first analysis of the atmosphere of the hot Jupiter HIP 65Ab. Using near-infrared high-resolution observations from the IGRINS spectrograph, we detect H2O and CO absorption in the dayside atmosphere of HIP 65Ab. Using a high-resolution retrieval framework, we find a CO abundance of log(CO) = − 3.85 − 0.36 + 0.33 , which is slightly underabundant with expectation from solar composition models. We also recover a low-water abundance of log(H2O) = −4.42 ± 0.18, depleted by 1 order of magnitude relative to a solar-like composition. Upper limits on the abundance of all other relevant major carbon- and oxygen-bearing molecules are also obtained. Overall, our results are consistent with a sub-stellar metallicity but slightly elevated C/O. Such a composition may indicate that HIP 65Ab accreted its envelope from beyond the water snowline and underwent a disk-free migration to its current location. Alternatively, some of the oxygen on HIP 65Ab could be condensed out of the atmosphere, in which case the observed gas-phase abundances would not reflect the true bulk envelope composition.

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Vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet

Cited by 29 publications

References 90 publications

JWST Measurements of ¹³C, ¹⁸O, and ¹⁷O in the Atmosphere of Super-Jupiter VHS 1256 b

JWST Measurements of ¹³C, ¹⁸O, and ¹⁷O in the Atmosphere of Super-Jupiter VHS 1256 b

The Inhomogeneity Effect. III. Weather Impacts on the Heat Flow of Hot Jupiters

A Subsolar Metallicity on the Ultra-short-period Planet HIP 65Ab

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Vanadium oxide and a sharp onset of cold-trapping on a giant exoplanet

Cited by 29 publications

References 90 publications

JWST Measurements of 13C, 18O, and 17O in the Atmosphere of Super-Jupiter VHS 1256 b

JWST Measurements of 13C, 18O, and 17O in the Atmosphere of Super-Jupiter VHS 1256 b

The Inhomogeneity Effect. III. Weather Impacts on the Heat Flow of Hot Jupiters

A Subsolar Metallicity on the Ultra-short-period Planet HIP 65Ab

Contact Info

Product

Resources

About

JWST Measurements of ¹³C, ¹⁸O, and ¹⁷O in the Atmosphere of Super-Jupiter VHS 1256 b

JWST Measurements of ¹³C, ¹⁸O, and ¹⁷O in the Atmosphere of Super-Jupiter VHS 1256 b