Computing extinction maps of star nulling interferometers

TL;DR

This paper analyzes how the design choices of spatial filtering and achromatic phase shifter subsystems impact the extinction maps of spaceborne nulling interferometers used for exoplanet detection, providing analytical and numerical insights.

Contribution

It introduces analytical relationships and numerical simulations to evaluate the influence of SF and APS designs on nulling map performance in interferometers.

Findings

Design variations significantly affect extinction map quality.

Different SF and APS configurations lead to variable fringe contrasts.

Mathematical relationships are broadly applicable to multi-aperture interferometers.

Abstract

Herein is discussed the performance of spaceborne nulling interferometers searching for extra-solar planets, in terms of their extinction maps projected on-sky. In particular, it is shown that the designs of Spatial Filtering (SF) and Achromatic Phase Shifter (APS) subsystems, both required to achieve planet detection and characterization, can sensibly affect the nulling maps produced by a simple Bracewell interferometer. Analytical relationships involving cross correlation products are provided and numerical simulations are performed, demonstrating marked differences in the aspect of extinction maps and the values of attained fringes contrasts. It is concluded that depending on their basic principles and designs, FS and APS will result in variable capacities for serendipitous discoveries of planets orbiting around their parent star. The mathematical relationships presented in this paper are assumed to be general, i.e. they should apply to other types of multi-apertures nulling interferometers.