PI: Laurence Trafton, University of Texas at Austin, email@example.com
Address: Astronomy Department, 2515 Speedway, Stop 1400, Austin, TX 78712, USA
CoI: John Lacy, University of Texas at Austin
CoI: Thomas Greathouse, Southwest Research Institute
Title: Investigating the Response of the Unknown Source of Uranus' Thermospheric Emission to Seasonally Changing Insolation
Abstract: During the 2007 equinox of Uranus, we mapped the planet using Gemini/TEXES in the pure rotational S(1) emission line of \aH2 and obtained a spectrum of the S(2) line with the slit set along the central meridian to investigate the thermospheric energy balance and to constrain its unknown source of excess heating at a time when all latitudes were visible (Trafton et al. 2012). This map revealed a symmetric emission pattern with no indication of a seasonal phase lag expected from the radiative time constant. This suggests that Uranus' \aH2 emission may look significantly different now, a third of the way to solstice (P=84 yr) when the sub-Earth latitude is +28\deg. A comparison with the equinox maps should reveal whether the unknown dominant thermospheric heating process is connected to insolation. We therefore propose to repeat the TEXES observations of Uranus' \aH2 S(1) & S(2) emission lines taken during the 2007 equinox with the goal of helping to constrain the long standing unknown dominant process responsible for heating Uranus' thermosphere.
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