We present a new method for numerical propagation through Lyot-style coronagraphs using finite occulting masks. Standard methods for coronagraphic simulations involve Fast Fourier Transforms (FFT) of very large arrays, and computing power is an issue for the design and tolerancing of coronagraphs on segmented Extremely Large Telescopes (ELT) in order to… (More)
Directly detecting thermal emission from young extrasolar planets allows measurement of their atmospheric compositions and luminosities, which are influenced by their formation mechanisms. Using the Gemini Planet Imager, we discovered a planet orbiting the ~20-million-year-old star 51 Eridani at a projected separation of 13 astronomical units. Near-infrared… (More)
The purpose of this paper is to present the results of a theoretical study pertaining to the feasibility of PIAA units using Deformable Mirrors. We begin by reviewing the general derivation of the design equations driving PIAA. We then show how to solve these equations for square apertures and show the performance of pure PIAA systems in the ray optics… (More)
The local geometry, energy stabilization, and pseudolocal t 1u vibration mode of the Cu + impurity in the alkali halide crystals have been investigated with the ab initio Perturbed Ion (aiPI) cluster-in-the-lattice methodology. The electronic structure of diierent clusters, containing up to 179 ions, has been computed for 9 Cu:AX systems (A: The… (More)
SUMMARY The Gemini Planet Imager Exoplanet Survey (GPIES) has observed approximately 17% of the 600 targets in its 890 hour campaign to directly image young, massive exoplanets about nearby stars. We present an update of the pre-survey performance simulations using GPI's on-sky performance data in the form of post-processed, angular separation-dependent… (More)
We have spatially resolved five debris disks (HD 30447, HD 35841, HD 141943, HD 191089, and HD 202917) for the first time in near-infrared scattered light by reanalyzing archival Hubble Space Telescope (HST)/NICMOS coronagraphic images obtained between 1999 and 2006. One of these disks (HD 202917) was previously resolved at visible wavelengths using the… (More)
Two diierent theoretical approaches to the total energy of solids have been applied to describe the equations of state (EOS) of ionic halides and oxides. The rst one is the ab initio Perturbed Ion (aiPI) model, a quantum-mechanical technique that solves the Hartree-Fock equations of a crystal in a localized Fock space. The second one is an interatomic force… (More)
We present a method of deriving effective core potentials ͑ECP's͒ for negative and positive ions. These ECP's are adapted to ionic crystals and can be used as components of an embedding model in most quantum chemistry codes. Cluster-in-the-lattice calculations of several defects and impurity centers in MgO are examined as a test.