http://arxiv.org/abs/1603.03646
We use high-resolution ground-based observations from the VLT CRIRES instrument in December 2012 to identify sixteen previously undetected H3+ emission lines from Jupiter’s ionosphere. These emission lines are located in Jupiter’s 5-micron window (4.5-5.2 {\mu}m), an optically-thin region of the planet’s spectrum where the radiation mostly originates from the deep troposphere. The H3+ emission lines are so strong that they are visible even against this bright background. We measure the Doppler broadening of the H3+ emission lines in order to evaluate the kinetic temperature of the molecules, and we obtain a value of 1390$\pm$160 K. We also measure the relative intensities of lines in the {\nu}2 fundamental in order to calculate the rotational temperature, obtaining a value of 960$\pm$40 K. Finally, we use the detection of an emission line from the 2{\nu}2(2)-{\nu}2 overtone to measure a vibrational temperature of 925$\pm$25 K. We use these three independent temperature estimates to discuss the thermodynamic equilibrium of Jupiter’s ionosphere.
R. Giles, L. Fletcher, P. Irwin, et. al.
Mon, 14 Mar 16
10/47
Comments: 5 pages, 3 figures, accepted in A&A
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