UCL online tools: An application for computing H3+ cooling rate Dugan Witherick / Steve Miller / Nick Achilleos Miracle Computational Officer / Lecturers, Departments of Physics / Science and Technology Studies University College London JRA3 UCL: April 2010 What is H3+ ? A molecular ion which strongly radiates in the infrared wavelength region (3-4 micron) - transitions between ro-vibrational levels. Important element of energy budget for ionospheres of hydrogen-rich gas giants esp. Jupiter and Saturn. Especially auroral regions. For example: Aspects of H3+ emission A molecular ion which strongly radiates in the infrared wavelength region (3-4 micron) - transitions between ro-vibrational levels. Important element of energy budget for ionospheres of hydrogen-rich gas giants esp. Jupiter and Saturn. Especially auroral regions. For example, Jupiters auroral oval radiates of order W in the UV and IR bands. Clarke et al, Nature, 2002 Aspects of H3+ emission Departures from LTE become important in determining H3+ emission from the Jovian thermosphere, at altitudes above 500 km (zero-point=1 B level) (Melin et al, Icarus, 2005) Timescales for radiative de-excitation become competitive with collisional de- excitation. By ~2000 km altitude, typical excited vibrn levels have populations