Evidence for methane escape and strong seasonal and dynamical perturbations of Neptune's atmospheric temperatures

  title={Evidence for methane escape and strong seasonal and dynamical perturbations of Neptune's atmospheric temperatures},
  author={Glenn S. Orton and Thérèse Encrenaz and C{\'e}dric Leyrat and R. C. Puetter and A. James Friedson},
  journal={Astronomy and Astrophysics},
Aims. We studied the distribution of mid-infrared thermal emission from Neptune to determine the spatial variability of temperatures and the distribution of trace constituents, allowing us to determine the relative strengths of radiation and dynamics in its atmosphere. Methods. Mid-infrared images of the planet were taken at the Very Large Telescope on 1–2 September 2006. Results. These images reveal strong inhomogeneities in thermal emission. 17.6 and 18.7-µm images exhibit strong seasonally… Expand

Figures from this paper

Recovery and characterization of Neptune's near-polar stratospheric hot spot
Images of Neptune obtained in 2006 at ESO's Very Large Telescope (Orton et al., 2007, Astronomy & Astrophysics 473, L5) revealed a near-polar hot spot near 70°S latitude that was detectable inExpand
A hexagon in Saturn’s northern stratosphere surrounding the emerging summertime polar vortex
The Cassini spacecraft has provided an unprecedented characterisation of seasonal changes on Saturn, and the authors describe the development of a warm polar vortex in Saturn’s northern summer and show that the hexagon extends hundreds of kilometres from the troposphere into the stratosphere. Expand
Thermal imaging of Uranus: Upper-tropospheric temperatures one season after Voyager
Abstract We report on 18–25 μm thermal imaging of Uranus that took place between 2003 and 2011, a time span roughly one season after the thermal maps made by the Voyager-2 IRIS experiment in 1986. WeExpand
Seasonal Stratospheric Photochemistry on Uranus and Neptune.
Seasonal variations in hydrocarbons are predicted to be more muted on Uranus, despite the planet's very large obliquity, and radiative-transfer simulations demonstrate that latitude variations in Hydrocarbon abundances on both planets are potentially observable with future JWST mid-infrared spectral imaging. Expand
Neptune's Spatial Brightness Temperature Variations from the VLA and ALMA
We present spatially resolved (0.″1–1.″0) radio maps of Neptune taken from the Very Large Array and Atacama Large Millimeter/submillimeter Array between 2015 and 2017. Combined, these observationsExpand
Convective storms and atmospheric vertical structure in Uranus and Neptune
A combination of orbital and in situ data will be required to understand convection and its role in atmospheric dynamics in the ice giants, and by extension, in hydrogen atmospheres including Jupiter, Saturn and giant exoplanets. Expand
Neptune's atmospheric composition from AKARI infrared spectroscopy
Aims. Disk-averaged infrared spectra of Neptune between 1.8 and 13 μm, obtained by the AKARI infrared camera (IRC) in May 2007, have been analysed to (a) determine the globally-averaged stratosphericExpand
Ice Giant Circulation Patterns: Implications for Atmospheric Probes
This review seeks to reconcile the various competing circulation patterns from an observational perspective, accounting for spatially-resolved measurements of: zonal albedo contrasts and banded appearances; cloud-tracked zonal winds; temperature and para-H 2 measurements above the condensate clouds; and equator-to-pole contrasts in condensable volatiles in the deeper troposphere. Expand
The haze and methane distributions on Uranus from HST-STIS spectroscopy
Abstract We analyzed a data cube of Neptune acquired with the Hubble STIS spectrograph on August 3, 2003. The data covered the full afternoon hemisphere at 0.1 arcsec spatial resolution between 300Expand
Neptune’s global circulation deduced from multi-wavelength observations
Abstract We observed Neptune between June and October 2003 at near- and mid-infrared wavelengths with the 10-m W.M. Keck II and I telescopes, respectively; and at radio wavelengths with the VeryExpand


Thermal spectroscopy of Neptune: the stratospheric temperature, hydrocarbon abundances, and isotopic ratios
Abstract Portions of Neptune's disk-averaged spectrum were observed from the NASA/Infrared Telescope Facility in 1989 and 1990 with a cryogenic echelle array spectrometer, with resolution of ν/Δν ∼Expand
Thermal Maps of Jupiter: Spatial Organization and Time Dependence of Stratospheric Temperatures, 1980 to 1990
The spatial organization and time dependence of Jupiter's stratospheric temperatures have been measured by observing thermal emission from the 7.8-micrometer CH4 band. These temperatures, observedExpand
Distribution of Ethane and Methane Emission on Neptune
We present the first published spatially resolved images of Neptune's thermal emission. Our 7.7 and 11.7 μm images, taken on 2005 July 4 and 5 at the Gemini North telescope, show enhanced methane andExpand
Clouds, hazes, and the stratospheric methane abundance in Neptune.
Reanalysis of the Voyager PPS 7500-angstroms phase angle data utilizing the fCH4,s value derived here confirms the Pryor et al. result of a tropospheric CH4 haze opacity of a few tenths in the 22-30 degrees S latitude region, several times that of the Equatorial Region or of the globe. Expand
Thermal Structure and Para Hydrogen Fraction on the Outer Planets from Voyager IRIS Measurements
Abstract Voyager infrared spectra from Jupiter, Saturn, Uranus, and Neptune are used to infer latitude-height cross sections of temperature and para hydrogen fraction. A new inversion algorithm isExpand
The quasiquadrennial oscillation of Jupiter's equatorial stratosphere
A NEW 11-year record of Jupiter's stratospheric temperature1 shows an equatorial temperature oscillation with an apparent period of 4–5 years. Here we compare this oscillation to two long-periodExpand
The spectra of Uranus and Neptune at 8-14 and 17-23 microns
The 3-m NASA Infrared Telescope Facility was used to observe the disks of Uranus and Neptune between May 30 and June 1, 1985 in the 7-14 and 17-23 micron spectral regions. Maximum stratosphericExpand
Winds of Neptune - Voyager observations of cloud motions
High temporal and spatial resolution images acquired from Voyager cameras have been used to measure cloud motions to improve the meridional profile of the zonal mean circulation on Neptune. A wideExpand
Dynamics of Neptune's Major Cloud Features
Abstract We used Voyager 2 images of Neptune to investigate the dynamics of the Great Dark Spot (GDS), the Scooter, the Second Dark Spot (DS2), and the South Polar Features (SPF). Relative toExpand
Hydrocarbons in Neptune's stratosphere from Voyager infrared observations
Emission from the acetylene and ethane bands at 729 and 822 cm-1detected in the Voyager infrared spectra of Neptune has been analyzed. A large selection of low-spatial resolution spectra was used toExpand