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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. Journal of Astronomical Telescopes, Instruments, and Systems, 7 (2). Art. No. 021214. ISSN 2329-4221. doi:10.1117/1.JATIS.7.2.021214.

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A starshade suppresses starlight by a factor of 10¹¹ 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 was developed specifically for images taken with an internal coronagraph system and focused on the removal of quasi-static speckles. These methods are less useful for starshade images where such speckles are not present. We are 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 GLRT 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:Article
Related URLs:
URLURL TypeDescription Paper
Hu, Mengya0000-0003-4867-1367
Harness, Anthony0000-0002-1300-4321
Sun, He0000-0003-1526-6787
Kasdin, N. Jeremy0000-0002-6963-7486
Additional Information:© 2021 The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Paper 20132SS received Aug. 29, 2020; accepted for publication Feb. 26, 2021; published online Mar. 26, 2021. This work was supported by Caltech-JPL NASA (Grant No. NNN12AA01C). The authors would like to thank the anonymous reviewers for their many helpful comments and suggestions. A. H. 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
Issue or Number:2
Record Number:CaltechAUTHORS:20210323-143428036
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Official Citation:Mengya (Mia) Hu, Anthony Harness, He Sun, and N. Jeremy Kasdin "Exoplanet detection in starshade images," Journal of Astronomical Telescopes, Instruments, and Systems 7(2), 021214 (26 March 2021).
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:05 Aug 2021 18:15

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