Effect of H₂S on the Near-infrared Spectrum of Irradiation Residue and Applications to the Kuiper Belt Object (486958) Arrokoth
Abstract
On 2019 January 1, the New Horizons spacecraft flew by (486958) Arrokoth, a small body in the Kuiper Belt that is the most distant object ever visited by a spacecraft. A strong unidentified absorption band was observed in the spectrum of Arrokoth at 1.8 μm. We report here experimental evidence suggesting that the near-infrared spectrum of Arrokoth is indicative of sulfur-rich, tholin-like organic residue. The spectra of organic residues produced by irradiating ice mixtures "with H₂S" CH₃OH:NH₃:H₂S:H₂O (3:3:3:1) and "without H₂S" CH₃OH:NH₃:H₂O (3:3:1) were measured to study the effect of H₂S. The "with H₂S" sulfur-rich laboratory-synthesized organic residue displays an absorption band at 1.8 μm that is absent in the spectrum of "without H₂S" sample. This feature matches the Arrokoth spectrum better than any other expected material. This suggests the past presence of H₂S ice on the surface of Arrokoth and a role for Kuiper Belt objects as a key S reservoir in the early solar system.
Additional Information
© 2021. The American Astronomical Society. Received 2021 April 15; revised 2021 May 11; accepted 2021 May 21; published 2021 June 17. This work has been supported by the NASA/RDAP program and by the Keck Institute for Space Studies (KISS). This work has been conducted at the JPL, Caltech, under a contract with the National Aeronautics and Space Administration (NASA) and at the Caltech Division of Geological and Planetary Sciences.Attached Files
Published - Mahjoub_2021_ApJL_914_L31.pdf
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Additional details
- Alternative title
- Effect of H2S on the Near-infrared Spectrum of Irradiation Residue and Applications to the Kuiper Belt Object (486958) Arrokoth
- Eprint ID
- 109646
- Resolver ID
- CaltechAUTHORS:20210629-165229618
- Keck Institute for Space Studies (KISS)
- NASA/JPL/Caltech
- Created
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2021-06-29Created from EPrint's datestamp field
- Updated
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2021-06-29Created from EPrint's last_modified field
- Caltech groups
- Keck Institute for Space Studies, Division of Geological and Planetary Sciences