Giant Planet Observations with the <i>James Webb Space Telescope</i>

Norwood, James; Moses, J. I.; Fletcher, Leigh N.; Orton, Glenn S.; Irwin, Patrick G. J.; Atreya, S. K.; Rages, K.; Cavalié, T.; Sánchez‐Lavega, A.; Hueso, R.; Chanover, N. J.

doi:10.1088/1538-3873/128/959/018005

Cited by 35 publications

(34 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given their extraordinary sensitivity, bandwidth, and spectral and spatial resolutions, future complementary ALMA and JWST observations will certainly help to shed light on the recent extraordinary influx of exogenic material from the inner ring system to Saturn's stratosphere, as captured by Cassini in its final orbits Perry et al 2018;Mitchell et al 2018;Hsu et al 2018). These future observations (Lellouch 2008;Norwood et al 2016), 85°S 70°S 50°S 30°S 10°S 0°1 0°N 30°N 50°N 50°N-220W 50°N-300W 70°N 85°N Fig. 15.…”

Section: Resultsmentioning

confidence: 73%

Herschel map of Saturn’s stratospheric water, delivered by the plumes of Enceladus

Cavalié

Hue

Hartogh

et al. 2019

A&A

View full text Add to dashboard Cite

Context. The origin of water in the stratospheres of Giant Planets has been an outstanding question ever since its first detection by ISO some 20 years ago. Water can originate from interplanetary dust particles, icy rings and satellites and large comet impacts. Analysis of Herschel Space Observatory observations have proven that the bulk of Jupiter's stratospheric water was delivered by the Shoemaker-Levy 9 impacts in 1994. In 2006, the Cassini mission detected water plumes at the South Pole of Enceladus, placing the moon as a serious candidate for Saturn's stratospheric water. Further evidence was found in 2011, when Herschel demonstrated the presence of a water torus at the orbital distance of Enceladus, fed by the moon's plumes. Finally, water falling from the rings onto Saturn's uppermost atmospheric layers at low latitudes was detected during the final orbits of Cassini's end-of-mission plunge into the atmosphere. Aims. In this paper, we use Herschel mapping observations of water in Saturn's stratosphere to identify its source. Methods. Several empirical models are tested against the Herschel-HIFI and -PACS observations, which were collected on December 30, 2010, and January 2 nd , 2011 (respectively). Results. We demonstrate that Saturn's stratospheric water is not uniformly mixed as a function of latitude, but peaking at the equator and decreasing poleward with a Gaussian distribution. We obtain our best fit with an equatorial mole fraction 1.1 ppb and a half-width at half-maximum of 25˝, when accounting for a temperature increase in the two warm stratospheric vortices produced by Saturn's Great Storm of 2010-2011. Conclusions. This work demonstrates that Enceladus is the main source of Saturn's stratospheric water.

show abstract

Section: Resultsmentioning

confidence: 73%

Herschel map of Saturn’s stratospheric water, delivered by the plumes of Enceladus

Cavalié

Hue

Hartogh

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…In addition, the James Webb Space Telescope (JWST), which is due to be operational shortly (currently delayed launch date Marchto-June, 2019), will be able to provide spatially-resolved spectroscopic maps of Uranus and Neptune. Of particular interest onboard JWST is the Medium Resolution Spectrometer (MRS) of the MIRI instrument (Rieke et al, 2015), an Integral Field Unit (IFU) with the capability to provide spatially-resolved 5-28 µm spectroscopy across the planetary disks (Norwood et al, 2016).…”

Section: Implications For Future Observations and Modelingmentioning

confidence: 99%

“…Future 1D, 2D, and 3D models could add complexity, as needed, to explain observations. We present our full model results in the journal supplementary material in the hopes that they will be of use in analyzing future observations, including potential spatially resolved infrared spectral observations from JWST (e.g., Norwood et al, 2016) and potential future spacecraft missions to the ice giants (e.g., Hofstadter et al, 2017;Mousis et al, 2017).…”

Section: Implications For Future Observations and Modelingmentioning

confidence: 99%

Seasonal stratospheric photochemistry on Uranus and Neptune

Moses

Fletcher

Greathouse

et al. 2018

Icarus

Self Cite

144

View full text Add to dashboard Cite

A time-variable 1D photochemical model is used to study the distribution of stratospheric hydrocarbons as a function of altitude, latitude, and season on Uranus and Neptune. The results for Neptune indicate that in the absence of stratospheric circulation or other meridional transport processes, the hydrocarbon abundances exhibit strong seasonal and meridional variations in the upper stratosphere, but that these variations become increasingly damped with depth due to increasing dynamical and chemical time scales.At high altitudes, hydrocarbon mixing ratios are typically largest where the solar insolation is the greatest, leading to strong hemispheric dichotomies between the summer-to-fall hemisphere and winter-to-spring hemisphere. At mbar pressures and deeper, slower chemistry and diffusion lead to latitude variations that become more symmetric about the equator. On Uranus, the stagnant, poorly mixed stratosphere confines methane and its photochemical products to higher pressures, where chemistry and diffusion time scales remain large. Seasonal variations in hydrocarbons are therefore predicted to be more muted on Uranus, despite the planet's very large obliquity. Radiativetransfer simulations demonstrate that latitude variations in hydrocarbons on both planets are potentially observable with future JWST mid-infrared spectral imaging. Our seasonal model predictions for Neptune compare well with retrieved C 2 H 2 and C 2 H 6 abundances from spatially resolved ground-based observations (no such observations currently exist for Uranus), suggesting that stratospheric circulation -which was not included in these modelsmay have little influence on the large-scale meridional hydrocarbon distributions on Neptune, unlike the situation on Jupiter and Saturn.We describe our photochemical models in section 2, present and discuss the results for the seasonal and meridional variations in hydrocarbons on Uranus and Neptune in section 3, compare the theoretical predictions with available observations in section 4, and discuss implications for future observations and modeling in section 5.

show abstract

“…This part of the spectrum is of particular interest to prepare for James Webb Space Telescope (JWST) image observations with the NIRCAM instrument of Jupiter to Neptune since JWST will achieve a spatial resolution better than Hubble Space Telescope (HST) from 0.7 to 2.1 microns (Norwood et al 2016). In this work, we profusely refer to a number of previous studies that served as an external reference for the absolute reflectivity values we obtain in this work.…”

Section: Introductionmentioning

confidence: 99%

Temporal and spatial variations of the absolute reflectivity of Jupiter and Saturn from 0.38 to 1.7μm with PlanetCam-UPV/EHU

Mendikoa¹,

Sánchez‐Lavega²,

Pérez‐Hoyos³

et al. 2017

A&A

View full text Add to dashboard Cite

Aims. We provide measurements of the absolute reflectivity of Jupiter and Saturn along their central meridians in filters covering a wide range of visible and near-infrared wavelengths (from 0.38 to 1.7 µm) that are not often presented in the literature. We also give measurements of the geometric albedo of both planets and discuss the limb-darkening behavior and temporal variability of their reflectivity values for a period of four years (2012)(2013)(2014)(2015)(2016).Methods. This work is based on observations with the PlanetCam-UPV/EHU instrument at the 1.23 m and 2.2 m telescopes in Calar Alto Observatory (Spain). The instrument simultaneously observes in two channels: visible (VIS; 0.38-1.0 µm) and short-wave infrared (SWIR; 1.0-1.7 µm). We obtained high-resolution observations via the lucky-imaging method. Results. We show that our calibration is consistent with previous independent determinations of reflectivity values of these planets and, for future reference, provide new data extended in the wavelength range and in the time. Our results have an uncertainty in absolute calibration of 10-20%. We show that under the hypothesis of constant geometric albedo, we are able to detect absolute reflectivity changes related to planetary temporal evolution of about 5-10%.

show abstract

Giant Planet Observations with the James Webb Space Telescope

Cited by 35 publications

References 44 publications

Herschel map of Saturn’s stratospheric water, delivered by the plumes of Enceladus

Herschel map of Saturn’s stratospheric water, delivered by the plumes of Enceladus

Seasonal stratospheric photochemistry on Uranus and Neptune

Temporal and spatial variations of the absolute reflectivity of Jupiter and Saturn from 0.38 to 1.7μm with PlanetCam-UPV/EHU

Contact Info

Product

Resources

About