Astrophysics Seminar: Sethupathy Subramanian, University of Notre Dame


Location: 214 Debartolo (View on map )

Modeling Magnetically Channeled Winds in 3D: I. Isothermal Simulations of a Magnetic O Supergiant

Sethupathy Subramanian
Graduate Student
University of Notre Dame

In this talk, the first set of 3D magnetohydrodynamic (MHD) simulations performed with the Riemann-Geomesh code is presented. We study the dynamics of the magnetically channeled winds of magnetic massive stars in full 3D using a code that is uniquely suited to spherical problems. Specifically, we perform isothermal simulations of a smooth wind on a rotating star with a tilted, initially dipolar field. We compare the mass-loss, angular momentum loss, and magnetospheric dynamics of a template star (with the properties that are reminiscent of the O4 supergiant ζ-Pup) over a range of rotation rates, magnetic field strengths, and magnetic tilt angles. The simulations are run up to a quasi-steady state and the results are observed to be consistent with the existing literature, showing the episodic centrifugal breakout events of  the mass outflow, confined by the magnetic field loops that form the closed magnetosphere of the star. The catalogued results provide perspective on how angular momentum varies for different configurations of rotation rate, magnetic field strength and large magnetic tilt angles. In agreement with previous 2D MHD studies, we find that high magnetic confinement reduces the overall mass-loss rate, and  higher rotation increases the mass-loss rate. In addition, we estimate the angular-momentum evolution, spin-down time, and mass-loss evolution of magnetic massive stars for different values of magnetic field strength, rotation rate, and dipole tilt.

Hosted by Prof. Balsara

All interested persons are invited to attend in person or on zoom. Email for zoom link.