Michelson Postdoctoral Fellowship Recipients

2005 Postdoctoral Fellows

Ruslan Belikov
Princeton University

2-Mirror Pupil Mapping Coronagraph with Wavefront Correction: Theory and Experiment

The Terrestrial Planet Finder-Coronagraph (TPF-C) project requires a high contrast imaging system capable of attaining a contrast ratio of 10-10. Many coronagraph designs have been proposed as a solution to this formidable task. One of the designs currently being developed at Princeton University is 2-mirror pupil mapping, whose significant advantage is that it does not lose any light. This is an extremely attractive feature, because the light from extrasolar planets is very faint. However, some concerns were recently raised as to how well conventional wavefront sensing and correction methods will work with 2-mirror pupil mapping. If these concerns can be resolved, and a successful 2-mirror pupil mapping coronagraph demonstrated, there will be a significant improvement in data collection times for the TPF coronagraph mission, leading to both scientific and economic benefits. The proposed work consists of a theoretical and experimental study of 2-mirror pupil mapping coronagraphs, focusing on wavefront correction. The goal of the work is to demonstrate a prototype satisfying TPF contrast requirements at the end of the 2-year funding period.

Ruslan is currently an Astrophysicist at NASA Ames Research Center.

Michael Ireland
California Institute of Technology

Development of Optical Interferometric Polarimetry (OIP) in the Near Infra-Red

Optical Interferometric Polarimetry (OIP) offers a new and unique way to explore the environments in which exoplanets form. I will undertake a research program that will develop experimental OIP methods capable of characterizing scattered light from disks around young stars. The seeing that affects interferometric observations on earth affects all polarization states of light equally. This means that as a differential technique, OIP can be independent of atmospheric effects. I will develop these techniques both at the Palomar Testbed Interferometer (PTI) and at an aperture-masking system behind the PALAO adaptive optics system at the Hale 200 inch telescope. Using this aperture masking system I will also continue development of another high contrast method: closure-phase based techniques for detecting faint companions and asymmetric structure. Together, these techniques will enable unique characterization of dust around Young Stellar Objects (YSOs) such as Herbig Ae/Be stars, characterization of dust around Vega-like stars and a survey for close brown dwarf companions around young stars. OIP will open-up a new observable parameter space, and represents one of the last remaining frontiers of ground-based optical interferometry.

Michael is currently an ANU Future Fellow at Macquarie University in Sydney, Australia.

Amaya Moro-Martin
Princeton University

Signatures of Planets in Debris Disks

In a planetary system with a belt of planetesimals and interior giant planets, the trapping of dust in mean motion resonances with the planet, and the ejection of particles due to gravitational scattering, create structure in the dust disk. Because debris disk structure is sensitive to long period planets, complementing a parameter space not covered by other methods, we can learn about the diversity of planetary systems by studying these "dusty fingerprints". Dr. Moro-Martin proposes to use a self consistent combination of 3-D numerical tools for the simulation of debris disk structure, and a 3-D radiative transfer code for the calculation of their emergent SED and brightness density distribution at different wavelengths. These models will be useful for the interpretation of spatially resolved images e.g. by ALMA, and spatially unresolved spectrophotometry observations by Spitzer, in terms of planetary architectures. Physically realistic initial conditions will be determined by a planetesimal formation code that calculates the location of the dust-producing planetesimals and the perturbing planets. Additionally, she proposes to explore the effects of stochastic dust production, gas drag and mutual grain collisions on the shaping of the disk's structure.

Amaya is currently an Assistant Astronomer at STScI and an Associate Research Scientist at The Johns Hopkins University.