Detecting Exoplanets in the Presence of Exozodiacal Dust Profiles

TL;DR

This paper addresses the challenge of detecting exoplanets obscured by exozodiacal dust in direct imaging, proposing analysis methods to distinguish point sources from dust profiles, especially with broader PSFs and limited data.

Contribution

It introduces new data analysis approaches tailored for identifying exoplanets amidst complex exozodiacal dust profiles in direct detection imaging.

Findings

Analysis of typical exozodi profiles

Evaluation of image data analysis methods

Strategies for high-confidence exoplanet detection

Abstract

For exoplanet direct detection mission concepts such as Terrestrial Planet Finder or Exoplanet Probe, light from the exozodiacal dust tends to obscure any exoplanets present in the image. Data analysis methods to identify point sources against this background have been very simple, traditionally with the simplifying assumption that the exozodi is uniformly distributed, just as our local zodiacal background is uniform over several-arcsec scales. However, the typical size of an exozodi cloud is expected to be comparable to the typical exoplanet orbital radii, or at least those of greatest interest_ the "habitable zone" range from 0.7-1.5 AU. When a direct detection instrument is reduced in size for cost reasons, the point spread function (PSF) becomes broader, making it more difficult to distinguish a point source from a "blob" of exozodi light. In this case, the shot-noise limited integration time may not be enough; instead we may need an elevated signal-to-noise ratio and/or later measurements to resolve ambiguities in the image data, identify a point source with a calculable and high confidence level, and isolate the exozodi and exoplanet contributions to the observed light profile. We will examine some typical profiles and a few methods of analyzing image data, with the goal of structuring an approach to this data analysis problem.