Supernova Progenitors, Stellar Remnants, and their Binary Companions

Northwestern University, Evanston IL

Investigators

Abstract

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: X-ray and pulsar binaries, gamma-ray bursts, extrasolar planets, gravitational-wave sources, supernova (SN) progenitors, cosmology, and especially transient astronomy. Observational advances have transformed the landscape and have highlighted the limitations of current modeling attempts. At the same time binary evolution modeling has not advanced significantly in the past decade; in turn, this has limited our ability to understand and interpret a number of current observational results related to binary populations. Building on their past experience, the investigators in this project will advance the physical sophistication of binary modeling and compact object formation and evolution. They will develop the next-generation binary-populations simulation tool (PSyDLib) with major, key advantages for self-consistent, physical modeling. The team will take advantage of the continued increase in computational power and the public availability of MESA, a versatile, robust stellar structure and evolution code. All the simulation codes will be made publicly available for other research projects. This project will take advantage of the PI's established connections with local schools (urban and suburban in the Chicago area), prior/current work with high-school teachers, and astronomy's appeal to children to address a critical need in elementary- and middle-school level STEM education. At all school levels the Next Generation Science Standards that are currently being implemented call for the introduction and use of computational thinking and modeling. However, in this area most school teachers do not have expertise and voice their need for professional development and appropriate curriculum materials. In collaboration with small teams of experienced teachers, the PI will develop computational astronomy curriculum materials. The PI will also capitalize on past work on astronomy visualizations and develop new ones for mass transfer in binaries and X-ray binary formation. The PI will use them extensively at public outreach presentations at Chicago's Adler Planetarium and the Evanston High School new planetarium. The PI will also involve two female graduate students who will be trained in advanced computation, hence contributing to a diverse, globally competitive STEM workforce. More technically, the team will develop new modules and an innovative hybrid software structure to incorporate (i) realistic mass-transfer sequences and physical assessment of stability, (ii) advanced treatment of common-envelope evolution eliminating the need for ad-hoc parameterization, and (iii) self-consistent orbital evolution for the general case of eccentric, asynchronous binaries due to tides and mass transfer. The project's science goals focus on studies of (i) core-collapse supernovae in terms of the physical properties of both their progenitors and their binary companions and compare to observational results from supernova surveys and (ii) high-mass X-ray binaries in the Milky Way and the Magellanic Clouds, which provide a plethora of observed systems with very different properties than originally expected. Given the more substantial XRB samples, the investigators will actually use the comparisons in (ii) to calibrate their models and assess the reliability of predictions for (i). The anticipated results will not only help to explain current observations but will also provide motivation and predictions for future multi-wavelength observations.