REU Supplement for SP0031550

Overview: The study of binary stellar systems has attracted renewed attention in the past decade as they are shown to play a critical role in a wide range of astronomy areas: from X-ray and pulsar binaries and all gamma-ray bursts, to extrasolar planets, gravitational-wave sources, supernova progenitors, and cosmology, and especially in the area of transient astronomy (recognized in New Worlds, New Horizons 2010). Observational advances have transformed the landscape and have highlighted the limitations of current modeling attempts. Specifically, (i) large-scale supernova surveys have revealed surprises regarding explosion progenitors and associated binary companions, with the whole community agreeing that single-star modeling is inadequate and quantitative binary evolution models are needed; (ii) observations of X-ray Binary (XRB) populations in our own and nearby galaxies have advanced dramatically over the last decade; not only the XRB samples have increased and statistics have become reliable, but unexpected correlations and trends have been firmly established. Nevertheless, binary evolution modeling has not advanced significantly in the past decade. Current simulation tools incorporate old analytical fits to single-star models which lead to unnecessarily strict assumptions and hamper physical, self-consistent treatment of binary interaction; these weaknesses have limited our ability to understand the origin and interpret a number of current observational results related to binary populations. Intellectual Merit: So far the study of the evolution of binary stars has focused either (i) on the detailed study of distinct evolutionary process or individual observed systems with detailed stellar structure/evolution and hydrodynamics tools, or (ii) on the modeling of population characteristics with both semianalytical, order-of-magnitude analyses and large-scale synthesis simulations, which however use oversimplified treatments of stellar evolution. The dramatic advancements in observations of supernovae and massive X-ray binaries motivate, in fact beg, for the next-generation modeling tools that can address population properties with self-consistent physical modeling of the stellar systems involved and with the best predictive power possible. We propose to build on our past experience and to advance the sophistication level of theoretical modeling of binary stars and compact object formation and evolution. We will take advantage of the continued increase of computational power and the public availability of MESA, a versatile, fast, and yet robust stellar structure and evolution code. We will develop a unique simulation tool (named BiPSyn-DL) for binary star populations specific key advantages over past modeling tools. We will focus on studying (i) core-collapse supernovae in terms of the physical properties of both their progenitors and their binary companions to be able to compare with the explosion of relevant observations from supernova surveys; (ii) high-mass X-ray binaries in the Milky Way and the Magellanic Clouds, that provide a plethora of observed systems with very different properties than originally expected. Given the more substantial samples of XRBs, we will actually use the comparisons in (ii) to calibrate our models and assess the reliability of predictions for (i). We anticipate that our results will not only help explaining current observations, but also provide motivation and predictions for future multi-wavelength observations. Broader Impacts: We will take advantage of the PI’s established connections with local s