Dr. Michael Browns research with this award will provide a unique window into seasonal change and the methane hydrological cycle on Titan; this window will come at a critical time, when the Cassini spacecraft is focusing intense scientific scrutiny on the satellite, and when Titan is likely to be undergoing its most dramatic seasonal changes. Dr. Brown will develop innovative methods to study the temporal and spatial variation of the clouds on Titan on time scales as short as hours and as long as several years and relate the observed clouds to Titans atmospheric circulation and geological features. Titan is the only body other than the earth that appears to have a major active hydrological cycle and presents the first opportunity to understand how such a cycle would work in a non-terrestrial context. The project relies on observing capabilities developed by Dr. Brown which allow him and his group to intensively study Titan s clouds. First, they have developed the unique capability of obtaining frequent high-spatial-resolution imaging of Titan from the largest telescopes in the world. While normal telescope scheduling would force an observer to obtain a small number of full nights of observation, Dr. Browns group is now routinely obtaining large numbers of short observations at the Keck and Gemini Observatories. These observations are uniquely suited for observing the full range of cloud phenomena that Titan present and for monitoring Titan for seasonal change expected as south polar summer moves into fall equinox. Even frequent observations are not sufficient to detect some of the large short-lived clouds which possibly dominate precipitation on Titan. To understand the frequency of these cloud systems Dr. Brown is installing a new dedicated robotic telescope at Palomar Observatory. The robotic observatory will be able to detect the existence of even relatively small clouds on Titan on an hourly basis throughout the observing seasons. With eight total years of observations acquired by the end of the proposal period, fundamental question about cloud activity will be able to be addressed for the first time, such as: What are the timescales for formation and dissipation of clouds of the smallest to the largest sizes seen? Is the current period of frequent cloudiness related to the recent southern summer solstice? Are clouds preferentially present at particular Titan longitudes? Members of the team are currently experimenting with additional daily observations from the Infrared Telescope Facility (IRTF) infrared spectrograph which, if successful, will give the group a second observing station capable of detecting the presence of even smaller clouds and measuring their heights. Critical to the interpretation of the hydrological cycle, this research group is developing collaborations with atmospheric scientists and geologists to use these observations of the seasonal cycle of cloud activity on Titan to understand the full hydrological cycle on Titan and how it varies with time and location. Together these projects will provide the first long term quantitative data on seasonal change and the hydrological cycle on Titan.
These reaserch activities will have a major impact on the education and training of all of the students and post-doctoral scholars involved. A major aspect of the work will be commissioning and gaining experience using a robotic telescope soon to be installed at Palomar Observatory. Once commissioned, this telescope will be available for all of the research and teaching activities of Dr. Brown, including, in particular, undergraduate students joining the group for the summer through Caltech s Summer Undergraduate Research Foundation (SURF) program. Moreover, Dr. Brown is working with Scitech, the manufacturer of the robotic telescope, to help define and refine priorities for astronomical usage of automated telescopes in the hopes that astronomers will finally be able to have access to off-the-shelf turnkey robotic telescope facilities for a wide variety of usages. ***
