{"id":497763,"date":"2026-06-13T12:29:24","date_gmt":"2026-06-13T12:29:24","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/497763\/"},"modified":"2026-06-13T12:29:24","modified_gmt":"2026-06-13T12:29:24","slug":"an-unidentified-absorption-feature-at-5-11-%ce%bcm-on-the-surface-of-titan-and-pluto-from-jwst-spectroscopy","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/497763\/","title":{"rendered":"An Unidentified Absorption Feature At 5.11 \u03bcm On The Surface Of Titan And Pluto From JWST Spectroscopy"},"content":{"rendered":"<p>                                    <img decoding=\"async\" src=\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/06\/An-Unidentified-Absorption.png\" alt=\"An Unidentified Absorption Feature At 5.11 \u03bcm On The Surface Of Titan And Pluto From JWST Spectroscopy\"\/><\/p>\n<p>\n                                                                                                            NIRSpec average spectrum of Titan (black) compared with a radiative transfer calculation in which the surface albedo decreases smoothly with wavelength beyond 4.9 \u00b5m (red). The blue line shows the difference between the observed and synthetic spectra, shifted by 0.005 for clarity. The 5.11-\u00b5m absorption is clearly missing in the model. The small mismatch below 4.93 \u00b5m is due to a component of the non-LTE CO emission not included in the model. \u2014 astro-ph.EP                                                                                                    <\/p>\n<p>Titan possesses a thick N2-CH4 atmosphere that makes it difficult to study its surface spectroscopically. The chemical composition of the solid surface of Titan thus remains very uncertain.<\/p>\n<p>By leveraging JWST\u2019s high sensitivity and large spectral coverage, we searched for any signature from Titan\u2019s surface in the broad and less explored 5-\u03bcm atmospheric window. We also investigated the JWST spectrum of Pluto which has a thin Titan-like atmosphere.<\/p>\n<p>We made selections of JWST NIRSpec and MIRI spectra around Titan\u2019s disk center and compared the NIRSpec average spectrum with a radiative transfer model including gas and haze opacity.<\/p>\n<p>We detected an unidentified absorption in both NIRSpec and MIRI spectra of Titan centered at 5.113 \u03bcm (1956 cm\u22121) and 6-7% deep. The width of the feature is 0.024\u00b10.0008 \u03bcm (9.2\u00b10.3 cm\u22121) in the NIRSpec spectrum recorded on the trailing side and is possibly 25% narrower in the MIRI spectrum of the leading side.<\/p>\n<p>This absorption most likely originates from the surface. We could not identify this signature among published laboratory spectra of ices relevant to Titan\u2019s atmospheric compounds but present a few plausible candidates.<\/p>\n<p>A 4-5% deep absorption is also present in the MIRI spectrum of Pluto but is about 3 times broader than on Titan\u2019s trailing side.<\/p>\n<p>B. B\u00e9zard, E. Lellouch, M. Camarca, J. I. Lunine, E. Quirico, C. A. Nixon, N. A. Teanby, P. Rannou, S. Rodriguez, M. Es-Sayeh, S. K. Trumbo, A. C. Souza-Feliciano, P. Lavvas, T. Bertrand, I. Wong, N. Pinilla-Alonso, G. L. Villanueva<\/p>\n<p>Comments: Accepted for publication in Astronomy &amp; Astrophysics<br \/>Subjects: Earth and Planetary Astrophysics (astro-ph.EP)<br \/>Cite as: arXiv:2606.13350 [astro-ph.EP] (or arXiv:2606.13350v1 [astro-ph.EP] for this version)<br \/><a href=\"https:\/\/doi.org\/10.48550\/arXiv.2606.13350\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">https:\/\/doi.org\/10.48550\/arXiv.2606.13350<\/a><br \/>Focus to learn more<br \/>Submission history<br \/>From: Bruno B\u00e9zard<br \/>[v1] Thu, 11 Jun 2026 13:39:36 UTC (66 KB)<br \/><a href=\"https:\/\/arxiv.org\/abs\/2606.13350\" target=\"_blank\" rel=\"noreferrer noopener nofollow\">https:\/\/arxiv.org\/abs\/2606.13350<\/a><br \/>Astrobiology, Astrochemistry,<\/p>\n","protected":false},"excerpt":{"rendered":"NIRSpec average spectrum of Titan (black) compared with a radiative transfer calculation in which the surface albedo decreases&hellip;\n","protected":false},"author":2,"featured_media":497764,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[145160,10803,213169,61,60,31807,14354,87999,10505,82,2811,13271],"class_list":["post-497763","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-astro-ph-ep","tag-atmosphere","tag-https-astrobiology-com-2026-06-astrochemistry","tag-ie","tag-ireland","tag-jwst","tag-miri","tag-nirspec","tag-pluto","tag-science","tag-spectroscopy","tag-titan"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/497763","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=497763"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/497763\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/497764"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=497763"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=497763"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=497763"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}