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Exoplanet Detection in Starshade Images

Hu, Mengya and Harness, Anthony and Sun, He and Kasdin, N. Jeremy (2021) Exoplanet Detection in Starshade Images. . (Unpublished)

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A starshade suppresses starlight by a factor of 1E11 in the image plane of a telescope, which is crucial for directly imaging Earth-like exoplanets. The state of the art in high contrast post-processing and signal detection methods were developed specifically for images taken with an internal coronagraph system and focus on the removal of quasi-static speckles. These methods are less useful for starshade images where such speckles are not present. This paper is dedicated to investigating signal processing methods tailored to work efficiently on starshade images. We describe a signal detection method, the generalized likelihood ratio test (GLRT), for starshade missions and look into three important problems. First, even with the light suppression provided by the starshade, rocky exoplanets are still difficult to detect in reflected light due to their absolute faintness. GLRT can successfully flag these dim planets. Moreover, GLRT provides estimates of the planets' positions and intensities and the theoretical false alarm rate of the detection. Second, small starshade shape errors, such as a truncated petal tip, can cause artifacts that are hard to distinguish from real planet signals; the detection method can help distinguish planet signals from such artifacts. The third direct imaging problem is that exozodiacal dust degrades detection performance. We develop an iterative generalized likelihood ratio test to mitigate the effect of dust on the image. In addition, we provide guidance on how to choose the number of photon counting images to combine into one co-added image before doing detection, which will help utilize the observation time efficiently. All the methods are demonstrated on realistic simulated images.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Sun, He0000-0003-1526-6787
Kasdin, N. Jeremy0000-0002-6963-7486
Additional Information:Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). This work is supported by Caltech-JPL NASA grant NNN12AA01C. The authors thank the anonymous reviewers for their many helpful comments and suggestions. AH is a guest co-editor of this starshade special section.
Funding AgencyGrant Number
Subject Keywords:Starshade, Image processing, Generalized likelihood ratio test, Exoplanet detection, High contrast imaging
Record Number:CaltechAUTHORS:20210323-143428036
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108535
Deposited By: Tony Diaz
Deposited On:24 Mar 2021 20:58
Last Modified:24 Mar 2021 20:58

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