A Charging Analysis for JWST
The James Webb Space Telescope (JWST) will orbit around the 2nd Lagrange point. During orbit, JWST and its Integrated Science Instrument Module (ISIM) will experience extreme space environments and a constant dose of radiation. Concern over these adverse environmental effects lead me to perform a charging analysis for JWST and ISIM. For the analysis, I modeled the range in voltage the spacecraft would experience under a wide variety or magnetosphereic conditions. Unfortunately, most of my research is protected by ITAR. However, I can report that over its planned 10 year mission life, JWST will only charge to a voltage of -40 Volts, which should not pose a threat to its operations.
A Search for Variable White Dwarfs
The white dwarf (WD) stage is the most common end stage in stellar evolution. The temperature and luminosity of a WD directly correlates with its age. As a WD cools, it passes through several temperature regimes where non-radial g-mode oscillations occur that are manifested by microvariability. Most of these oscillations are driven by hydrogen or helium ionization zones in the outer layers of stars. Recently, Montgomery et al. (2008 ApJ 678 L51) discovered the prototype of a new class of variable WDs with carbon-dominated atmospheres. All of the above regimes of variability in WDs are limited to relatively hot stars (Teff ≥ 10,000 K). At present, no cooler WDs are known to exhibit pulsations. My research goal is to observe cooler WDs in order to empirically model these radical pulsation modes.