On the Detection of Exomoons Transiting Isolated Planetary-mass Objects

Limbach, Mary Anne and Vos, Johanna M. and Winn, Joshua N. and Heller, René and Mason, Jeffrey C. and Schneider, Adam C. and Dai, Fei (2021) On the Detection of Exomoons Transiting Isolated Planetary-mass Objects. The Astrophysical Journal Letters, 918 (2). L25. ISSN 2041-8205

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Abstract

All-sky imaging surveys have identified several dozen isolated planetary-mass objects (IPMOs) far away from any star. Here we examine the prospects for detecting transiting moons around these objects. We expect transiting moons to be common, occurring around 10%–15% of IPMOs, given that close-orbiting moons have a high geometric transit probability and are expected to be a common outcome of giant planet formation. The IPMOs offer an advantage over other directly imaged planets in that high-contrast imaging is not necessary to detect the photometric transit signal. For at least 30 (>50%) of the currently known IPMOs, observations of a single transit with the James Webb Space Telescope would have low enough forecast noise levels to allow for the detection of an Io- or Titan-like moon. The intrinsic variability of the IPMOs will be an obstacle. Using archival time-series photometry of IPMOs with the Spitzer Space Telescope as a proof of concept, we found evidence for a fading event of 2MASS J1119–1137 AB that might have been caused by intrinsic variability but is also consistent with a single transit of a habitable-zone 1.7 R⊕ exomoon. Although the interpretation of this particular event is inconclusive, the characteristics of the data and the candidate signal suggest that Earth-sized habitable-zone exomoons around IPMOs are detectable with existing instrumentation.

Item Type: Article
Subjects: AP Academic Press > Physics and Astronomy
Depositing User: Unnamed user with email support@apacademicpress.com
Date Deposited: 08 May 2023 05:22
Last Modified: 03 Oct 2024 03:49
URI: http://info.openarchivespress.com/id/eprint/1200

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