Cool Stars 14 - Submitted Abstract # 222 This version created on 05 October 2006 Cool Stars in a hot place: The early cluster environment of the Sun and other low mass stars Eric Gaidos, University of Hawaii Infrared surveys of molecular clouds indicate that most stars form in dense but loosely bound or unbound clusters that disperse in 1-10 Myr. The presence of the products of short-lived radionuclides in primitive meteorites strongly suggests a proximate supernova in early Solar System history which in turn requires a dense stellar environment for the primordial Sun. Several previous investigators have also used the dynamics of outer Solar System (OSS) bodies as a constraint on the paleoenvironment of the Sun. Here, I reconsider those constraints in light of our evolving understanding of the formation and evolution of the OSS, and show that the dynamics of known OSS offers little or no constrain on plausible values of tides and frequency of close stellar passages by stars. However, the presence or absence of yet more distant, undetected bodies may offer a meaningful constrain on the dynamical environment of the nascent Sun. I also present preliminary work to determine the statistical properties of environments experienced by cluster stars using the NBODY4 and NBODY6 codes. Specifically, I examine the range of possible histories experienced by solar-mass stars, including the probability of capture into orbit around a Type I supernova progenitor. The simulations are also designed to determine differences in those distribution with those of M stars due to mass segregation in the cluster potential. These different dynamical histories equate to differences in fluxes of short-lived radionuclide and ultraviolet radiation experienced by disks, with potential consequences for planet formation. ----------------------------------