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Inferring Late-stage Enrichment of Exoplanet Atmospheres from Observed Interstellar Comets

Seligman, Darryl Z. and Becker, Juliette and Adams, Fred C. and Feinstein, Adina D. and Rogers, Leslie A. (2022) Inferring Late-stage Enrichment of Exoplanet Atmospheres from Observed Interstellar Comets. Astrophysical Journal Letters, 933 (1). Art. No. L7. ISSN 2041-8205. doi:10.3847/2041-8213/ac786e.

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The discovery of the first two interstellar objects implies that, on average, every star contributes a substantial amount of material to the galactic population by ejecting such bodies from the host system. Because scattering is a chaotic process, a comparable amount of material should be injected into the inner regions of each system that ejects comets. For comets that are transported inwards and interact with planets, this Letter estimates the fraction of material that is accreted or outward-scattered as a function of planetary masses and orbital parameters. These calculations indicate that planets with escape velocities smaller than their current-day orbital velocities will efficiently accrete comets. We estimate the accretion efficiency for members of the current census of extrasolar planets and find that planetary populations including but not limited to hot and warm Jupiters, sub-Neptunes, and super-Earths can efficiently capture incoming comets. This cometary enrichment may have important ramifications for postformation atmospheric composition and chemistry. As a result, future detections and compositional measurements of interstellar comets will provide direct measurements of material that potentially enriched a subpopulation of the extrasolar planets. Finally, we estimate the efficiency of this enrichment mechanism for extrasolar planets that will be observed with the James Webb Space Telescope (JWST). With JWST currently operational and these observations imminently forthcoming, it is of critical importance to investigate how enrichment from interstellar comet analogs may affect the interpretations of exoplanet atmospheric compositions.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Seligman, Darryl Z.0000-0002-0726-6480
Becker, Juliette0000-0002-7733-4522
Adams, Fred C.0000-0002-8167-1767
Feinstein, Adina D.0000-0002-9464-8101
Rogers, Leslie A.0000-0003-0638-3455
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2022 April 15; revised 2022 June 1; accepted 2022 June 14; published 2022 June 29. We thank Fred Ciesla, Megan Mansfield, Jacob Bean, Rafael Luque, Eliza Kempton, Samuel Cabot, Dan Fabrycky, Sebastián Marino, Quentin Kral, and Mark Wyatt for useful suggestions. We thank the anonymous reviewer for extremely insightful comments and constructive suggestions that greatly strengthened the scientific content of this manuscript. J.B. has been supported by the Heising-Simons 51 Pegasi b postdoctoral fellowship. A.D.F. acknowledges support by the National Science Foundation Graduate Research Fellowship Program under grant No. (DGE-1746045). L.A.R. gratefully acknowledges support from the Research Corporation for Science Advancement through a Cottrell Scholar Award. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research also has made use of NASA's Astrophysics Data System. Facility: Exoplanet Archive.
Funding AgencyGrant Number
Heising-Simons Foundation51 Pegasi b Fellowship
NSF Graduate Research FellowshipDGE-1746045
Cottrell Scholar of Research CorporationUNSPECIFIED
Subject Keywords:Interstellar objects; Exoplanet atmospheres; Comets; Chemical enrichment
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Interstellar objects (52); Exoplanet atmospheres (487); Comets (280); Chemical enrichment (580)
Record Number:CaltechAUTHORS:20220725-156450000
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Official Citation:Darryl Z. Seligman et al 2022 ApJL 933 L7
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115823
Deposited By: George Porter
Deposited On:27 Jul 2022 17:43
Last Modified:27 Jul 2022 17:43

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