b'Retrograde and Co-orbital Planet Packing in Alpha Centauri ABChristopher R. Robinson andBilly Quarles, and Jack LissauerSponsor: Dr. QuarlesSatellites within the solar system can have either prograde or retrograde orbits as evidenced by the many moons of Jupiter.We examine the orbital stability of multiple planetary systems that also have a stellar companion, specifically using the Alpha Centauri AB binary system.The orbital stability is determined via n-body numerical simulations of 26 planets orbiting either stellar component of the binary system.In contrast to prograde orbits, we find that the planetary orbits are more eccentric over time and apsidal locking with binary orbit is rare.As a result, the spacing between pairs of planets must be equivalent to or larger than the prograde case.This has implications for exoplanet statistics and estimates of planetary habitability because the number of Earthlike planets within the habitable zone is limited.Statistical Analysis of the Likelinessof Extraterrestrial LifeIan McLeanSponsor: Dr. LeakeThe question of life on other planets has been universally puzzling since man existed. Though it may be often pondered, it has proven to be an increasingly difficult and complex problem to model. Through alterations of the Drake Equation and a better understanding of its parameters, it is possible to estimate the likeliness of microscopic prokaryotic-like unicellular life, macroscopic multicellular life, and intelligent life. Moreover, with the given equations, it is possible to estimate the number of each considered stage of life in our galaxy and the average distance between two inhabited planets. As expected, the estimated prevalence of microscopic prokaryotic-like unicellular life is more than macroscopic life and thus, more than intelligent life. From these results, we can infer reasons for not finding life outside Earth. Moreover, we can start to better understand where to look for life.Comparison of Karstic Denudation Ratesin the Watersheds of Suwannee River Floridaand Green River KentuckyAlexcia Nicole DunnSponsor: Dr. DenizmanKarst features are affected by climatic zones and the lithology of the area. Variability in climatic factors such as temperature, humidity, and amount of runoff, along with the age and type of porosity present within that limestone terrane, can lead to differences in the rate of denudation. The Green River watershed of Kentucky and the Lower Suwannee River watershed (below the Withlacoochee) are selected to compare their karstic erosion rates. Water monitoring stations along each river, both upstream and downstream, to reflect input and output to the system are selected for the collection of both discharge and water quality data. Mass flux is calculated for each station using the collected data. The relationship between mass flux and discharge values will be applied to each stations corresponding flow duration curve ranges and weighted by the proportion of time each discharge value occurs for a more accurate estimation of mass flux. This estimation is applied to a variation of the Corbel equation and calculates the net limestone denudation rates further data analysis is needed, and final calculations will be presented.46'