Discovery of heavy negative ions in Titan's ionosphere
Publication date: 28 November 2007
Authors: Coates, A.J. et al.
Journal: Geophysical Research Letters
Volume: 34
Issue: 22
CiteID: L22103
Year: 2007
Copyright: American Geophysical Union
Titan's ionosphere contains a rich positive ion population including organic molecules. Here, using CAPS electron spectrometer data from sixteen Titan encounters, we reveal the existence of negative ions. These ions, with densities up to ~100 cm-3, are in mass groups of 10-30, 30-50, 50-80, 80-110, 110-200 and 200+ amu/charge. During one low encounter, negative ions with mass per charge as high as 10,000 amu/q are seen. Due to their unexpectedly high densities at ~950 km altitude, these negative ions must play a key role in the ion chemistry and they may be important in the formation of organic-rich aerosols (tholins) eventually falling to the surface.
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