Eve Ostriker has joined the faculty
Eve Ostriker, a leading theorist working on star formation, has moved from the University of Maryland to Princeton.
Eve's early work centered on analytic studies of magnetohydrodynamic (MHD) accretion flows onto magnetized stars, and MHD winds from protostellar accretion disks. Magnetically regulated accretion is thought to be ubiquitous in astrophysical systems. However, solving the MHD equations to compute the structure and kinematics of such flows, even in simple geometries and assuming time-independent flows, presents enormous challenges. As a postdoc at Berkeley, Ostriker obtained a steady-state solution for the funnel flow, which remains to date the only self-consistent analytical model of this magnetosphere interaction region. She has studied the asymptotic structure of an MHD wind showing that magnetic fields could collimate stellar winds into jets with properties similar to observed flows from young stars. In later work at the University of Maryland, she studied the stability properties of such flows; investigating the conditions under which such collimated winds and their underlying disks are stable. Their analysis helps to explain, in part, why protostellar jets are able to propagate over such large distances without being disrupted.
Over the past 10 years, Eve has been using direct numerical simulations to study the properties of MHD turbulence in molecular clouds, and how it affects the star formation process. These studies were the first to show that turbulent dissipation in magnetized media proceeds almost as rapidly as in unmagnetized media, contrary to long-held expectations. Moreover, the statistical properties of the turbulence (density, velocity fluctuations, etc.) are in good agreement with the observed properties of molecular clouds. This work has had a profound impact on the theory of star formation: it implies molecular clouds and star formation must be short-lived and very dynamic.
Most recently, Eve has worked on understanding what controls the star formation rate in galaxies. She has developed a theory for the regulation of star formation based on the dual constraints of dynamical and thermal equilibrium in the interstellar medium. She has shown that star formation is self-regulating due to feedback from heating and supernova. While these processes have long been thought to be important, her theory provides a precise and quantitative prediction for how feedback works.