Abstract
Here we present observations and simulations of oxygen particle
bombardment into Titan’s thermosphere that represents a new class of
upper atmospheric stimulus. We find that these large bursts of energetic
oxygen ions contain sufficient energy to perturb Titan’s thermosphere,
if the energy is applied at the right altitude. In this study we present
Cassini observations during the T20 flyby of Titan in 2006 specifically
from the Cassini Magnetospheric Imaging Instrument (MIMI; Krimigis et
al. [2004]) and the Cassini Plasma Spectrometer (CAPS; Young et al.
[2004]). We utilize simulations using the Titan-Global Ionosphere
Thermosphere Model to assess the impact of energetic oxygen bursts
similar to the one observed during T20 on the thermospheric structure.
We find that energy deposited higher in Titan’s thermosphere has a much
greater effect on the temperatures that Cassini would observe from the
INMS instrument. These higher altitude energy deposition events are
similar to those that occur from corotational oxygen and water group
ions in Saturn’s magnetosphere. We find that the more energetic heavy
ions tend to penetrate deeper into the thermosphere resulting in a much
more benign heating rate and minimal temperature change, however when
these events carry along lower energy thermal oxygen ions that will
deposit energy at higher altitudes the temperature change can be much
more substantial.