Thermal Infrared Imaging Spectroscopy of Shoemaker–Levy 9 Impact Sites: Spatial and Vertical Distributions of NH3, C2H4, and 10-μm Dust Emission

Griffith, C. A.; Bézard, Bruno; Greathouse, T. K.; Kelly, Douglas; Lacy, J. H.; Noll, K. S.

doi:10.1006/icar.1997.5752

Cited by 68 publications

(48 citation statements)

References 39 publications

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“…The presence of this amount of NH 3 at these low altitudes suggests an additional source in the lower stratosphere. Griffith et al (1997) suggested an additional thinlayer NH 3 source in the 15-to 30-mbar region (1-3 × 10 17 cm −2 ) for the K site ∼11 days after impact for a quiescent thermal profile. For the G region, our lineshape does not require a thinlayer source.…”

Section: Ammonia Abundancementioning

confidence: 96%

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Fast

Kostiuk

Romani

et al. 2002

Icarus

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Infrared emission lines of stratospheric ammonia (NHwith cold jovian air. During the first 4 days after impact, NH 3 was present primarily at altitudes above 1 mbar with a column density of (7.7 ± 1.6) × 10 17 cm −2 after 1 day and (3.7 ± 0.8) × 10 17 cm −2 after 4 days. (Errors represent precision.) We obtained >2.5 times more NH 3 than can be supplied by nitrogen from a large cometary fragment, suggesting a primarily jovian source for the NH 3 . By 18 days postimpact, a return to quiescent upper stratospheric temperature is retrieved for the G region, with an NH 3 column density of 7.3 × 10 17 cm −2 or more in the lower stratosphere, possibly supplied by NH 3 upwelling across an impact-heated and turbulent tropopause, which may have been masked by initial dust and haze. Above the 1-mbar level, the maximum retrieved column density decreased to 6.5 × 10 16 cm −2 . Comparison to photochemical models indicates that photolysis alone is not sufficient to account for the loss of NH 3 above 1 mbar by that time, even when chemical reformation of NH 3 is ignored. We speculate that the dispersion of plume material at high altitudes (above 1 mbar) is responsible for the change in the spectra observed a few days postimpact. Data on the K impact region provide qualitatively consistent results. c 2002 Elsevier Science (USA)

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Section: Ammonia Abundancementioning

confidence: 96%

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Fast

Kostiuk

Romani

et al. 2002

Icarus

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“…Finally, slow upwelling of tropospheric air (responsible for the presence of NH 3 in the stratosphere in both SL9 and the 2009 impacts, Griffith et al 1997;Fast et al 2002;Fletcher et al 2010) could have raised this newly-produced ethane into the lower stratosphere. But given that the small tropospheric abundance of C 2 H 6 (approximately 0.7 ppm at 200 mbar at 50 • S, Nixon et al 2007) is smaller than the quantities detected over the impact streak, some excess production of C 2 H 6 must have occurred.…”

Section: Hydrocarbon Enhancements Over the Impactmentioning

confidence: 99%

“…Infrared spectroscopy from IRSHELL in 1994 (Bézard 1997;Bézard et al 1997;Griffith et al 1997) demonstrated that compressional heating from the collapsing plume deposited excess energy in the 5−500 μbar region, at the lower boundary of the shock. The upper stratospheric heating caused enhanced emission from the strongest CH 4 lines in the ν 4 vibrational band near 7.7 μm, but was absent from the weaker lines probing the lower stratosphere.…”

Section: Introductionmentioning

confidence: 99%

Jupiter’s stratospheric hydrocarbons and temperatures after the July 2009 impact from VLT infrared spectroscopy

Fletcher

Orton

Pater

et al. 2010

A&A

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Aims. Thermal infrared imaging and spectroscopy of the July 19, 2009 Jupiter impact site has been used to identify unique features of the physical and chemical atmospheric response to this unexpected collision. Methods. Images and high-resolution spectra of methane, ethane and acetylene emission (7−13 μm) from the 2009 impact site were obtained by the Very Large Telescope (VLT) mid-infrared camera/spectrometer instrument, VISIR. An optimal estimation retrieval algorithm was used to determine the atmospheric temperatures and hydrocarbon distribution in the month following the impact. Results. Ethane spectra at 12.25 μm could not be explained by a rise in temperature alone. Ethane was enhanced by 1.7−3.2 times the background abundance on July 26, implying production as the result of shock chemistry in a high C/O ratio environment, favouring an asteroidal origin for the 2009 impactor. Small enhancements in acetylene emission were also observed over the impact site. However, no excess methane emission was found over the impact longitude, either with broadband 7.9-μm imaging 21 h after the impact, or with center-to-limb scans of strong and weak methane lines between 7.9 and 8.1 μm in the ensuing days, indicating either extremely rapid cooling in the initial stages, or an absence of heating in the upper stratosphere (p < 10 mbar) due to the near-horizontal orientation of the impact. Models of 12.3-μm spectra are consistent with a ≈3 K rise in the lower stratosphere (p > 10 mbar), though this solution is highly dependent on the spectral properties of stratospheric debris. The enhanced ethane emission was localised over the impact streak, and was diluted in the ensuing weeks by redistribution of heated gases by zonal flow and mixing with the unperturbed jovian air. Conclusions. The different thermal energy deposition profiles, in addition to the highly reducing (C/O > 1) environment and shallow impactor angle, suggest that (a) the 2009 plume and shock-fronts did not reach the sub-microbar altitudes of the Shoemaker-Levy 9 plumes; and (b) models of a cometary impact are not directly applicable to the unique impact circumstances of July 2009.

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“…It has been also detected on Jupiter and Saturn in nonauroral regions (Bézard et al 2001). The analysis of the mass and distributions of C 2 H 4 on the Jupiter-orbiting comet SL9 was presented in Griffith et al (1997), and the investigation of the photochemistry on some hydrocarbons from the Infrared Space Observatory (ISO) observations was reported by Moses et al (2000). Again in Saturn, ethylene has recently been detected in the hot temperature beacon (Hesman et al 2012) region using the Composite Infrared Spectrometer (CIRS) with strong thermal emission at 10.5 µm.…”

Section: Introductionmentioning

confidence: 99%

First theoretical global line lists of ethylene (¹²C₂H₄) spectra for the temperature range 50−700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

Rey

Delahaye

Nikitin

et al. 2016

A&A

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We present the construction of complete and comprehensive ethylene line lists for the temperatures 50−700 K based on accurate ab initio potential and dipole moment surfaces and extensive first-principle calculations. Three lists spanning the [0−6400] cm −1 infrared region were built at T = 80, 160, and 296 K, and two lists in the range [0−5200] cm −1 were built at 500 and 700 K. For each of these five temperatures, we considered possible convergence problems to ensure reliable opacity calculations. Our final list at 700 K was computed up to J = 71 and contains almost 60 million lines for intensities I > 5 × 10 −27 cm/molecule. Comparisons with experimental spectra carried out in this study showed that for the most active infrared bands, the accuracy of band centers in our theoretical lists is better on average than 0.3 cm −1 , and the integrated absorbance errors in the intervals relevant for spectral analyses are about 1−3%. These lists can be applied to simulations of absorption and emission spectra, radiative and non-LTE processes, and opacity calculations for planetary and astrophysical applications.

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Thermal Infrared Imaging Spectroscopy of Shoemaker–Levy 9 Impact Sites: Spatial and Vertical Distributions of NH3, C2H4, and 10-μm Dust Emission

Cited by 68 publications

References 39 publications

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Jupiter’s stratospheric hydrocarbons and temperatures after the July 2009 impact from VLT infrared spectroscopy

First theoretical global line lists of ethylene (¹²C₂H₄) spectra for the temperature range 50−700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

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Thermal Infrared Imaging Spectroscopy of Shoemaker–Levy 9 Impact Sites: Spatial and Vertical Distributions of NH3, C2H4, and 10-μm Dust Emission

Cited by 68 publications

References 39 publications

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Temporal Behavior of Stratospheric Ammonia Abundance and Temperature Following the SL9 Impacts

Jupiter’s stratospheric hydrocarbons and temperatures after the July 2009 impact from VLT infrared spectroscopy

First theoretical global line lists of ethylene (12C2H4) spectra for the temperature range 50−700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres

Contact Info

Product

Resources

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First theoretical global line lists of ethylene (¹²C₂H₄) spectra for the temperature range 50−700 K in the far-infrared for quantification of absorption and emission in planetary atmospheres