Exoplanets & Exomoons

Direct Imaging Of Exoplanets

By Keith Cowing
Status Report
April 10, 2024
Filed under , , , , , ,
Direct Imaging Of Exoplanets
First evidence of gravitational instability clumps with planetary masses. On the left, the ALMA band 6 continuum image of the protoplanetary disk around the FUor star V960 Mon, and on the right the SPHERE/IRDIS polarized light image. Contours of the ALMA continuum are overlaid on both images, corresponding to levels of 3, 4, and 5 times σ. The ALMA signal showing the clumps share the same location of the spiral arms around the star. Image from Weber et al. (2023). — astro-ph.EP

Over the past 4 decades, the exploration of planets beyond our solar system has yielded the discovery of over 5,600 exoplanets orbiting different stars. Continuous advancements in instrumentation and cutting-edge techniques empower astronomers to unveil and characterize new exoworlds with increasing frequency.

Notably, direct imaging, also called high-contrast imaging (HCI), stands out as the only method capable of capturing photons emitted directly from the planetary bodies. This innovative technique proves particularly advantageous for scrutinizing nascent planetary systems, where planets shine brilliantly and emit significant heat during their initial developmental phases.

HCI provides comprehensive visuals of the entire system, encompassing the central star, potential circumstellar disks, and any additional companions. However, the complexity of imaging an object 10^6 fainter than its parent star necessitates state-of-the-art instrumentation. HCI demands cutting-edge tools such as exAO systems, telescopes exceeding 8 meters in diameter, coronagraphs, and modern imagers. The pivotal role of post-processing cannot be overstated in the quest for detecting and characterizing planets through HCI.

This method has not only facilitated the discovery of numerous planets but has also presented invaluable opportunities to explore the properties of young substellar companions, both planets and brown dwarfs. Insights into their interactions with parent disks or other companions within the system, the composition of their atmospheres, and the identification of still accreting planets, also known as “protoplanets,” contribute significantly to our understanding of planet formation scenarios. The continued refinement of HCI promises to unveil further revelations in the captivating field of exoplanetary exploration.

Zurlo Alice

Comments: Preprint of a chapter for the ‘Encyclopedia of Astrophysics’ (Editor-in-Chief Ilya Mandel, Section Editor Dimitri Veras) to be published by Elsevier as a Reference Module. The number of references was capped
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2404.05797 [astro-ph.EP] (or arXiv:2404.05797v1 [astro-ph.EP] for this version)
Submission history
From: Alice Zurlo
[v1] Mon, 8 Apr 2024 18:00:18 UTC (8,651 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻