AAS 207th Meeting, 8-12 January 2006
Session 191 Extrasolar Planets
Oral, Thursday, 10:00-11:30am, January 12, 2006, Virginia

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[191.05] Study of Coronagraphic Techniques

V. Tolls (CfA), M.J. Aziz (Harvard University), R.A. Gonsalves (Tufts University), S.G. Korzennik (CfA), A. Labeyrie (Observatoire de Haute-Provence), R.G. Lyon (GSFC), G.J. Melnick (CfA), S. Somerstein, G. Vasudevan, R.A. Woodruff (Lockheed Martin Corp.)

Direct imaging of extra-solar planets is important for determining the properties of individual planets and to study multi-planet systems. Obtaining spectra of extra-solar planets enables us to constrain the composition of planetary atmospheres and surfaces, their climates, and their rotation periods. The techniques required to isolate and detect an extra-solar planet next to its host star are quite challenging and require significant improvement. SAO has set up a testbed to study coronagraphic techniques, starting with Labeyrie's multi-step speckle reduction technique. This technique expands the general concept of a coronagraph by incorporating a speckle corrector (phase or amplitude) and second occulter for speckle light suppression. The testbed consists of a coronagraph with high precision optics (2 inch spherical mirrors with lambda/1000 surface quality), lasers simulating the host star and the planet, and a single Labeyrie correction stage with a MEMS deformable mirror for the phase correction. The correction function is derived from images taken in and slightly out of the focal using phase diversity. In addition, we are using the testbed for occulter masks developed in collaboration with Harvard University and Lockheed Martin Corp. This testing is also supported by a high-precision mask scanner for mask characterization. This work was supported by NASA through grant NNG04GC57G.


The author(s) of this abstract have provided an email address for comments about the abstract: vtolls@cfa.harvard.edu

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