Dr. Dan Potter
Steward Obs., Univ. of Arizona

University of Florida Astronomy Colloquium - Feb 7th, 2006

High-Contrast Imaging of Circumstellar Disks and Extrasolar Planets with Differential Imaging Techniques

The detection and characterization of extrasolar planets and debris disks is challenging at optical and near-infrared wavelengths due to the high contrast ratios with their harboring stars. In this talk I will discuss how simultaneous multi-channel differential imaging techniques overcome some of these observational difficulties by enhancing contrast sensitivity though a suppression of the noise introduced by a time variable point spread function. I illustrate the application of the technique for the detection of circumstellar disks with observations obtained using the Hokupa`a 36 element adaptive optics system at the Gemini North telescope. In addition I will review the technique used in differential methane-band observations for the detection of methane-rich faint companions. Although beneficial, I show that intrinsic spectral contrasts of the target are not necessarily required to take advantage of the noise suppression afforded by the differential imaging technique. Finally, I will discuss the instrumentation I am currently developing to overcome the limitations of traditionally employed differential imaging systems.