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Show COLLEGE OF SCIENCE UNDERGRADUATE RESEARCH ABSTRACTS Chris Tellesbo Ben Bromley INTERACTION BETWEEN BINARY STARS AND DARK MATTER Chris Tellesbo (Ben Bromley) Department of Physics & Astronomy University of Utah Dark matter is pervasive in the Universe, although it is only known through its gravitational interaction. I a m studying the interplay between dark matter and ordinary stars, specifically binaries, which are pairs of stars that orbit one another. The purpose of this project is to understand h o w dark matter may affect these otherwise stable systems on a large time scale. By simulating dark matter/binary star interactions, I a m seeking any noticeable changes in the stars'orbits that might assist in the detection of dark matter. I developed a computer program to track binaries in the presence of dark matter and calculate the subtle effects that dark matter might have on binary orbits. I have both a functional 4th-order leapfrog integrator as well as a functional 4th-order symplectic integrator, which encompasses time symmetry. This code examines these interactions by randomly orienting a binary system and shooting massless particles, simulating dark matter, into the system and tracking the energy and position of each body. By observing what happens under different orientations of the system I was able to draw possible conclusions about the long-term effect on the system. I present preliminary results showing that even with the occasional particle depositing energy into the system (Figure 1), the majority of particles take energy from the binary (Figure 2), resulting in a slow deterioration of the orbit. This work will eventually identify any astrophysical scenarios in which dark matter might have a long-term influence on the dynamics of tightly bound solar type stars. ! -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 Position (AU) -0.2 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 Position (AU) Figure 1. Anun tesij!»rs.ci(.!rijnu!i>tint^sxJ(msn.!;r.iin.iJ.<l)t TMiamlzSZitmsslJaiBia. In this Interaction, the test particle enters from the left, deposits energy In the system, and exits to the upper left The density of points Is Inversely proportional to velocity, Illustrating the loss of energy. Position (AU) 0.6 04 0.2 0 -0.2 -0 4 Star T w o ^^e»Jeeeelai(Jjjng5:6 • I X vV JV V. / -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 Position (AU) 74 •0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 Position (AU) Figure 2. AJBCPlMDnSerutlpji beiwieju. randomly oriented binary and a lest p a rude flmulMlnidaril inaflejr. The particle enters from the left deflects slightly and gains a small amount of energy taken from the binary. Position (AU) |
