Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns

Abstract The disparity between predicted sulfur abundances and identified reservoirs of sulfur in cold molecular clouds, also known as the sulfur depletion problem, has remained an ongoing debate over decades. Here, we show in laboratory simulation experiments that hydrogen sulfide (H2S) can be conv...

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Main Authors: Ashanie Herath, Mason McAnally, Andrew M. Turner, Jia Wang, Joshua H. Marks, Ryan C. Fortenberry, Jorge C. Garcia-Alvarez, Samer Gozem, Ralf I. Kaiser
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-61259-2
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author Ashanie Herath
Mason McAnally
Andrew M. Turner
Jia Wang
Joshua H. Marks
Ryan C. Fortenberry
Jorge C. Garcia-Alvarez
Samer Gozem
Ralf I. Kaiser
author_facet Ashanie Herath
Mason McAnally
Andrew M. Turner
Jia Wang
Joshua H. Marks
Ryan C. Fortenberry
Jorge C. Garcia-Alvarez
Samer Gozem
Ralf I. Kaiser
author_sort Ashanie Herath
collection DOAJ
description Abstract The disparity between predicted sulfur abundances and identified reservoirs of sulfur in cold molecular clouds, also known as the sulfur depletion problem, has remained an ongoing debate over decades. Here, we show in laboratory simulation experiments that hydrogen sulfide (H2S) can be converted on ice-coated interstellar grains in cold molecular clouds through galactic cosmic rays processing at 5 K to sulfanes (H2Sn; n = 2–11) and octasulfur (S8). This locks the processed hydrogen sulfide as high-molecular weight sulfur-containing molecules thus providing a plausible rationale for the fate of the missing interstellar sulfur. These sulfuretted molecules may undergo fractionated sublimation once the molecular cloud transforms into star forming regions. The isomeric identification of octasulfur rings (S8) coincides with the recent identification of elementary sulfur in the carbonaceous asteroid (162173) Ryugu, thus providing compelling evidence on the link between sulfur in cold molecular clouds and in our Solar System with, e.g., the Taurus Molecular Cloud (TMC) potentially accumulating an equivalent of 350 Earth masses of octasulfur.
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spelling doaj-art-f23fe44d8d03441b855a55bfb45bca302025-08-20T03:45:33ZengNature PortfolioNature Communications2041-17232025-07-0116111310.1038/s41467-025-61259-2Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crownsAshanie Herath0Mason McAnally1Andrew M. Turner2Jia Wang3Joshua H. Marks4Ryan C. Fortenberry5Jorge C. Garcia-Alvarez6Samer Gozem7Ralf I. Kaiser8Department of Chemistry, University of Hawaiʻi at MānoaDepartment of Chemistry, University of Hawaiʻi at MānoaDepartment of Chemistry, University of Hawaiʻi at MānoaDepartment of Chemistry, University of Hawaiʻi at MānoaDepartment of Chemistry, University of Hawaiʻi at MānoaDepartment of Chemistry and Biochemistry, University of MississippiDepartment of Chemistry, Georgia State UniversityDepartment of Chemistry, Georgia State UniversityDepartment of Chemistry, University of Hawaiʻi at MānoaAbstract The disparity between predicted sulfur abundances and identified reservoirs of sulfur in cold molecular clouds, also known as the sulfur depletion problem, has remained an ongoing debate over decades. Here, we show in laboratory simulation experiments that hydrogen sulfide (H2S) can be converted on ice-coated interstellar grains in cold molecular clouds through galactic cosmic rays processing at 5 K to sulfanes (H2Sn; n = 2–11) and octasulfur (S8). This locks the processed hydrogen sulfide as high-molecular weight sulfur-containing molecules thus providing a plausible rationale for the fate of the missing interstellar sulfur. These sulfuretted molecules may undergo fractionated sublimation once the molecular cloud transforms into star forming regions. The isomeric identification of octasulfur rings (S8) coincides with the recent identification of elementary sulfur in the carbonaceous asteroid (162173) Ryugu, thus providing compelling evidence on the link between sulfur in cold molecular clouds and in our Solar System with, e.g., the Taurus Molecular Cloud (TMC) potentially accumulating an equivalent of 350 Earth masses of octasulfur.https://doi.org/10.1038/s41467-025-61259-2
spellingShingle Ashanie Herath
Mason McAnally
Andrew M. Turner
Jia Wang
Joshua H. Marks
Ryan C. Fortenberry
Jorge C. Garcia-Alvarez
Samer Gozem
Ralf I. Kaiser
Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
Nature Communications
title Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
title_full Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
title_fullStr Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
title_full_unstemmed Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
title_short Missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
title_sort missing interstellar sulfur in inventories of polysulfanes and molecular octasulfur crowns
url https://doi.org/10.1038/s41467-025-61259-2
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