Latitudinal profiles of the jovian IR emissions of H-3(+) at 4 mu m with the NASA Infrared Telescope Facility: Energy inputs and thermal balance

We present ground-based observations of the jovian ionospheric H-3(+) emiss ion at 4 micrometers, using the CSHELL facility long-slit spectrograph at t he NASA Infrared Telescope Facility (IRTF) in Hawaii. The data were obtaine d during four consecutive nights from July 13 to July 16, 1996. The 30-arcs ec length slit of the spectrograph was aligned with the jovian CML, in orde r to get high-spatial, high-spectral resolution latitudinal profiles of the jovian H-3(+) emission. A self-consistent multi-emission-component (MEC) m odel, developed for the analysis of these latitudinal profiles, simulates t he emission from the vertical distribution of the ionization components kno wn to produce H-3(+) We initially identify these as solar-EUV photo-ionizat ion, auroral oval precipitation, and diffuse auroral precipitation. A fourt h component, mid-to-low (MTL)-latitude ionization is derived, and then fitt ed. InfraRed H-3(+) auroral: ovals follow closely the UV ovals as observed with the HST instruments WFPC2 and FOG. Our model shows that the auroral pr oduction rate is generally between a few and a few tens of times the EUV ra te. The MTL component production rate is 1 to 40% of the auroral rate in th e north, and 2 to 16% in the south. Input and output energies are scaled to solar EUV values. We assume an EUV insolation of 60 muW/m(2), equivalent t o a total jovian EUV insolation of 10(12)W. Scaled to the EUV input, planet wide integration of the components of our model produces the total hemisphe ric energy inputs associated with the aurora, the diffuse emission, and the MTL emission. The results are 1.22(+/-.25) x 10(12)W, 0.37(+/-.15) x 10(12 )W, and 0.65(+/-.32) x 10(12)W, respectively, for the north and 1.15(+/-.30 ) x 10(12)W, 0.21(+/-.10) x 10(12)W, and 0.64 (+/-.32)x 10(12)W for the sou th, respectively. We discusss the limitations of our scaling process, intro ducing the notion of emission efficiency with respect to a nominal 1000K/LT E H-3(+) emitter. The overall auroral emission is approximately 43 (+107, - 23)% of that measured in 1993. Our results show that H-3(+) controls the en ergy balance of the auroral regions above the homopause, as well as the equ atorial regions. (C) 2000 Academic Press.