Detection of H3+ auroral emission in Jupiter's 5-micron window

Journal article

We use high-resolution ground-based observations from the VLT CRIRES instrument in November 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 μm), 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 ± 160 K. We also measure the relative intensities of lines in the ν2 fundamental in order to calculate the rotational temperature, obtaining a value of 960 ± 40 K. Finally, we use the detection of an emission line from the 2ν2(2)-ν2 overtone to measure a vibrational temperature of 925 ± 25 K. We use these three independent temperature estimates to discuss the thermodynamic equilibrium of Jupiter’s ionosphere.

Authors: Giles, R; Fletcher, L; Irwin, P; al., E

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: EDP Sciences
• Journal: Astronomy and Astrophysics
• Publication date: 2016-04-14
• Acceptance date: 2016-03-11
• DOI: 10.1051/0004-6361/201628170
• EISSN: 1432-0746
• ISSN: 0004-6361