Anisotropic winds from close-in extra-solar planets

We present two-dimensional hydrodynamic models of thermally driven winds from highly irradiated, close-in extra-solar planets. We adopt a very simple treatment of the radiative heating processes at the base of the wind, and instead focus on the differences between the properties of outflows in multidimensions in comparison to spherically symmetric models computed with the same methods. For hot (T > 2 x 10^{4} K) or highly ionized gas, we find strong (supersonic) polar flows are formed above the planet surface which produce weak shocks and outflow on the night-side. In comparison to a spherically symmetric wind with the same parameters, the sonic surface on the day-side is much closer to the planet surface in multidimensions, and the total mass loss rate is reduced by almost a factor of four. We also compute the steady-state structure of interacting planetary and stellar winds. Both winds end in a termination shock, with a parabolic contact discontinuity which is draped over the planet separating the two shocked winds. The planetary wind termination shock and the sonic surface in the wind are well separated, so that the mass loss rate from the planet is essentially unaffected. However, the confinement of the planetary wind to the small volume bounded by the contact discontinuity greatly enhances the column density close to the planet, which might be important for the interpretation of observations of absorption lines formed by gas surrounding transiting planets.Comment: ApJ accepte

A robust high-sensitivity algorithm for automated detection of proteins in two-dimensional electrophoresis gels

The automated interpretation of two-dimensional gel electrophoresis images used in protein separation and analysis presents a formidable problem in the detection and characterization of ill-defined spatial objects. We describe in this paper a hierarchical algorithm that provides a robust, high-sensitivity solution to this problem, which can be easily adapted to a variety of experimental situations. The software implementation of this algorithm functions as part of a complete package designed for general protein gel analysis applications

Quasi all-speed schemes for magnetohydrodynamic flows in a wide range of Mach numbers

We present novel numerical schemes for ideal magnetohydrodynamic (MHD) simulations aimed at enhancing stability against numerical shock instability and improving the accuracy of low-speed flows in multidimensions. Stringent benchmark tests confirm that our scheme is more robust against numerical shock instability and is more accurate for low-speed, nearly incompressible flows than conventional shock-capturing schemes. Our scheme is a promising tool for tackling MHD systems, including both high and low Mach number flows.Comment: 9 pages, 4 figures, 1 tables, Conference series of ASTRONUM-2023. arXiv admin note: text overlap with arXiv:2108.0499

Digital Signal Processing Group

Contains an introduction and reports on nineteen research projects.U.S. Navy - Office of Naval Research (Contract N00014-77-C-0266)U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)National Science Foundation (Grant ECS80-07102)Bell Laboratories FellowshipAmoco Foundation FellowshipU.S. Navy - Office of Naval Research (Contract N00014-77-C-0196)Schlumberger-Doll Research Center FellowshipToshiba Company FellowshipVinton Hayes FellowshipHertz Foundation Fellowshi

Digital Signal Processing

Contains introduction and reports on seventeen research projects.U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)U.S. Navy - Office of Naval Research (Contract N00014-77-C-0266)National Science Foundation (Grant ECS80-07102)Bell Laboratories FellowshipAmoco Foundation FellowshipSchlumberger-Doll Research Center FellowshipSanders Associates, Inc.Toshiba Company FellowshipM.I.T. Vinton Hayes FellowshipHertz Foundation Fellowshi