![\"SPHEREx](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/01\/SPHEREx-Re-Observation-of-Interstellar.png\")
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\n (Top Insets) SPHEREx 0.75-5.0\u03bcm imaging of 3I\/ATLAS taken on 08-to-15-Dec2025. The 6.3\u2019x6.3\u2019 cutout contours are 5,20,&50 times the background noise; color bars are in MJy\/sr. The celestial North-and-East directions are shown (black-arrows), along with the anti-velocity (dashed-blue) and anti-sun (solid-red) directions. <\/p>\n
In December-2025, the NASA SPHEREx spacecraft re-observed ISO 3I\/ATLAS post-perihelion, finding a much more active object compared to August-2025 SPHEREx pre-perihelion observations, with marked evidence for development into an cometary body fully sublimating all its ices.<\/p>\n
The new imaging spectrophotometry is dominated by spatially resolved features due to dust scattered-light and thermal emission plus gas-emissions from CN (0.93 um), H2O (2.7 um), organic C-H (3.2 to 3.6 um), CO2 (4.25 to 4.27 um), and CO (4.6 to 4.8 um). The CO2 gas-coma continues to be extended out to a 3 arcmin radius.<\/p>\n
The continuum spectral signature of H2O-ice absorption has mostly disappeared, replaced by scattered-light plus thermal-emission from organo-silicaceous dust grains while the H2O gas-emission is 20 times brighter.<\/p>\n
All but the organics-gas comae are circularly symmetric, while a weak pear-shaped solar-pointing dust tail consistent with large dust grains is now present. The new appearance of CN and C-H features suggests that these species are contained either in H2O phases or were trapped under them.<\/p>\n
C.M. Lisse, YP. Bach, S.A. Bryan, P. M. Korngut, B.P. Crill, A.J. Cukierman, O. Dor\u00e9, A. Cooray, B. Fabinsky, A.L. Faisst, H. Hui, G.J. Melnick, C.H. Nguyen, Z. Rustamkulov, V. Tolls, M.W. Werner<\/p>\n
Comments: 6 pages, 1 figure, submitted to RNAAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2601.06759 [astro-ph.EP](or arXiv:2601.06759v1 [astro-ph.EP] for this version)
https:\/\/doi.org\/10.48550\/arXiv.2601.06759<\/a>
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Submission history
From: Carey Lisse
[v1] Sun, 11 Jan 2026 03:31:54 UTC (1,070 KB)
https:\/\/arxiv.org\/abs\/2601.06759<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"(Top Insets) SPHEREx 0.75-5.0\u03bcm imaging of 3I\/ATLAS taken on 08-to-15-Dec2025. The 6.3\u2019x6.3\u2019 cutout contours are 5,20,&50 times the…\n","protected":false},"author":2,"featured_media":250030,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[111,139,69,147,392],"class_list":["post-250029","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/250029","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=250029"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/250029\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/250030"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=250029"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=250029"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=250029"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}