{"id":41289,"date":"2026-04-08T12:20:35","date_gmt":"2026-04-08T10:20:35","guid":{"rendered":"https:\/\/karmaka.de\/?p=41289"},"modified":"2026-04-08T12:20:36","modified_gmt":"2026-04-08T10:20:36","slug":"the-volatile-inventory-of-3i-atlas-as-seen-with-jwst-miri","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=41289","title":{"rendered":"The Volatile Inventory of 3I\/ATLAS as Seen with JWST\/MIRI<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Matthew Belyakov, Ian Wong, Bryce T. Bolin, M. Ryleigh Davis, Steven J. Bromley, Carey M. Lisse, and Michael E. Brown<\/p>\n\n\n\n<p>The Astrophysical Journal Letters, Volume 1001, Number 1, Published: 8 April 2026<\/p>\n\n\n\n<p><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/2041-8213\/ae5700\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br><a href=\"https:\/\/iopscience.iop.org\/article\/10.3847\/2041-8213\/ae5700\/pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;We present the first spectroscopic characterization of an interstellar object at mid-infrared wavelengths. Postperihelion observations of 3I\/ATLAS (3I) using the JWST\/MIRI medium-resolution spectrometer were obtained on 2025 December 15\u201316 and 27, when the object was at heliocentric distances of 2.20 and 2.54 au, respectively. Our 5\u201328 \u03bcm spectra exhibit fluorescence features from several gaseous species, including the \u03bd2 band of H2O at 5.8\u20137.0 \u03bcm, the primary \u03bd2 and associated hot bands of CO2 around 15 \u03bcm, and a forbidden transition of atomic nickel at 7.507 \u03bcm. We also report the first direct detection of CH4 in an interstellar object. The sharp rise in CH4 production relative to H2O suggests past CH4 depletion from the outermost layers, with the observed CH4 emerging from unprocessed subsurface material. Comparison of the volatile production rates measured during the two epochs indicates a significant reduction in the overall outgassing over 12 days, with the measured H2O activity level dropping more steeply than other species. As shown through near-nucleus coma mapping, 3I continues to display an extended source of H2O production from icy grains entrained within the coma. Our production rate measurements confirm that 3I has a strongly enhanced CO2:H2O mixing ratio relative to typical solar system comets, as well as a somewhat enriched CH4:H2O value.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Matthew Belyakov, Ian Wong, Bryce T. Bolin, M. Ryleigh Davis, Steven J. Bromley, Carey M. Lisse, and Michael E. Brown The Astrophysical Journal Letters, Volume 1001, Number 1, Published: 8 April 2026 LINK (OPEN ACCESS)PDF&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[179,130],"tags":[6913,2090,2089,6033,1479,369],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41289"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=41289"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41289\/revisions"}],"predecessor-version":[{"id":41292,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/41289\/revisions\/41292"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=41289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=41289"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=41289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}