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Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiters Great Red SpotThe high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.
Document ID
20160010074
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Carlson, Robert W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Baines, Kevin H.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Anderson, M. S.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Filacchione, G.
(Istituto di Astrofisica Spaziale e Fisica Cosmica (INAF-IASF) Rome, Italy)
Simon, A. A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 5, 2016
Publication Date
March 19, 2016
Publication Information
Publication: Icarus
Publisher: Elsevier
Volume: 274
Subject Category
Space Radiation
Space Sciences (General)
Report/Patent Number
GSFC-E-DAA-TN31847
Funding Number(s)
CONTRACT_GRANT: NAS5-26555
Distribution Limits
Public
Copyright
Other
Keywords
Jupiter
Great Red Spot
Chromophores

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