{"id":38840,"date":"2025-08-06T09:26:52","date_gmt":"2025-08-06T07:26:52","guid":{"rendered":"https:\/\/karmaka.de\/?p=38840"},"modified":"2025-08-06T09:26:53","modified_gmt":"2025-08-06T07:26:53","slug":"spectral-characteristics-of-interstellar-object-3i-atlas-from-soar-observations","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=38840","title":{"rendered":"Spectral Characteristics of Interstellar Object 3I\/ATLAS from SOAR Observations<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"\n<p>Thomas H. Puzia, Rohan Rahatgaonkar, Juan Pablo Carvajal, Prasanta K. Nayak, Baltasar Luco<\/p>\n\n\n\n<p>revised and resubmitted to ApJL, draft version August 6, 2025<\/p>\n\n\n\n<p><a href=\"https:\/\/arxiv.org\/pdf\/2508.02777\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><\/p>\n\n\n\n<p class=\"justify-text\">&#8220;Interstellar objects (ISOs) provide unique insights into the building blocks and conditions of extrasolar planetary systems. The newly discovered object, 3I\/ATLAS (C\/2025 N1), represents the third known ISO after 1I\/&#8217;Oumuamua and 2I\/Borisov. We present initial spectroscopic characterizations of 3I using observations from the Goodman High Throughput Spectrograph on the 4.1 m SOAR Telescope in Chile during the night of July 3rd. The reflectance spectrum of 3I, covering 3700-7000 A, reveals a red continuum, comparable to extreme trans-Neptunian objects, with a weak UV-optical turnover indicative of complex carbonaceous and irradiated organics. At the time of observation, when 3I was at a heliocentric distance of 4.4 AU, we detected no discernible gas emission from canonical cometary species s (CN, C3, C2, CO+, [OI]). This is in agreement with expectations from our thermal-evolution model, which indicates sublimation-driven activity should commence once 3I\/ATLAS approaches smaller heliocentric distances. Nonetheless, the paradoxical situation of early onset coma without evidence of sublimation tracers calls for other dust-liberating mechanisms that ancient ISOs may be subjected to at large heliocentric distances.&#8221;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Thomas H. Puzia, Rohan Rahatgaonkar, Juan Pablo Carvajal, Prasanta K. Nayak, Baltasar Luco revised and resubmitted to ApJL, draft version August 6, 2025 PDF (OPEN ACCESS) &#8220;Interstellar objects (ISOs) provide unique insights into the building&#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":[6913,1870,6033,1479],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38840"}],"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=38840"}],"version-history":[{"count":1,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38840\/revisions"}],"predecessor-version":[{"id":38841,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/38840\/revisions\/38841"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=38840"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=38840"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=38840"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}