OBSERVATIONS OF THE 4-MICRON FUNDAMENTAL-BAND OF H-3+ IN JUPITER

Emission lines of the ν2 fundamental vibration-rotation band of H3+ have been detected in the northern and southern polar ionospheres of Jupiter. The recently discovered 2 μm overtone band of H3+ is currently absent from the spectra of Jupiter's poles, as are lines of several other "hot bands" of H3+ and 2 μm lines of H2, implying that physical conditions in Jupiter's auroral regions have changed considerably within a period of ∼1 yr. The present observations provide added evidence for a large abundance of H3+ in localized zones of the Jovian atmosphere.