Houston, TX 77005
12:00 p.m. Wednesday, Oct. 31, 2012
On Campus | Alumni
(1) We study partial eruption of a solar filament observed by SDO and STEREO-A on May 9, 2012. This filament was located in active region NOAA 11475, and consisted of two branches. During two days before filament eruption, filament threads were observed to transfer from lower branch to upper branch. The upper branch started rising slowly at 23:40 on May 9, and erupted away half an hour later, observed as a CME. During the eruption, the upper branch rotated about 120 degrees in counter-clockwise direction. We suggest the flux transfer may have lead the higher branch to lose equilibrium as a result of kink instability or torus instability.(2) The high-resolution cross-dispersed code echelle spectrometer and the Zeeman Analyzer of the 2.7 meter Harlan J. Smith Telescope at McDonald Observatory enable us to carry out high precision spectropolametric studies. It is always important to establish well the zero point and check the polarization efficiency of the instrumentation. To showcase the performance of these instruments, various tests have been performed. We have observed some late-type main sequence stars as our null standards as well as several well-studied Ap Stars which are believed to possess strong fields. Test results will be shown in this presentation.