{"id":5145,"date":"2025-08-10T17:55:27","date_gmt":"2025-08-10T08:55:27","guid":{"rendered":"https:\/\/sci.nao.ac.jp\/main\/?p=5145"},"modified":"2025-08-10T17:57:57","modified_gmt":"2025-08-10T08:57:57","slug":"20250810","status":"publish","type":"post","link":"https:\/\/sci.nao.ac.jp\/main\/highlights\/20250810","title":{"rendered":"ALMA High-Resolution Observations Reveal New Evidence for Bimodal Fragmentation and Multi-Scale Dynamical Mass Accretion in High-Mass Star Formation"},"content":{"rendered":"\n

For decades, formation of high-mass stars exceeding 8 solar masses has remained one of astronomy\u2019s greatest mysteries. In a recent study published in Astronomy & Astrophysics, a global team of astronomers, including researchers from Yunnan University, Shanghai Astronomical Observatory and Division of Science of NAOJ, has carried out cutting-edge observations toward a “hub-filament system” (HFS) molecular cloud\u2014a cradle of high-mass star formation, and has uncovered stunning new evidence that challenges current theories and illuminates the multi-scale, dynamical\u00a0 nature of high-mass stellar birth.<\/p>\n\n\n\n

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Figure 1.<\/strong> Left:<\/strong><\/em> Morphological structure of the hub-filament system (HFS) in target region I18308, showing core spacing distribution. The HFS molecular cloud consists of two distinct filamentary structures (F1 and F2) and a central hub clump. Right:<\/strong><\/em> Artistic illustration of multi-scale dynamic mass accretion.<\/figcaption><\/figure>\n\n\n\n

Using the world\u2019s most advanced (sub)millimeter interferometer, ALMA, the research team conducted ~3000AU resolution observations at the 1.3mm wavelength toward the HFS I18308 cloud, a high star-forming region with a textbook example of HFS morphologies (left panel, Figure 1).\u00a0 The team revealed dual fragmentation modes. Two hub-composing filaments (F1 and F2) exhibit a cylinder-like fragmentation mode, with the quasi-periodic core spacings regulated by the turbulence-dominated fragmentation mechanism. In contrast, the central hub clump shows a spherical-like fragmentation mode, with the core spacings regulated by gravity-dominated Jeans fragmentation mechanism. These findings challenge models predicting a single fragmentation mode across all density scales within molecular clouds (e.g., the global gravitational collapse model).<\/p>\n\n\n\n

Moreover, the team did not find high-mass prestellar cores surpassing 30 solar masses; and instead all relatively low-mass cores show a systematic increase in mass and density with evolution. These observed facts support a multi-scale accretion scenario: low-mass prestellar cores form via Jeans fragmentation in the hub, collapse into intermediate-mass protostars, and grow into high-mass stars through hierarchical mass accretion from the filaments, hub clump, and cores (right panel, Figure 1).<\/p>\n\n\n\n

Article Information<\/strong><\/p>\n\n\n\n

L. M. Zhen, H-L. Liu, X. Lu, Y. Cheng, R. Galv\u00e1n-Madrid, H. B. Liu, P. Sanhueza, T. Liu, D. T. Yang, F. Nakamura, S. H. Jiao, L. Chen, Y. Q. Guo, S. Y. Feng, Q. Zhang, X. C. Liu, K. Wang, Q. L. Gu, Q. Y. Luo, Y. Lin, P. S. Li, S. H. Li, K. Tanaka , A. E. Guzm\u00e1n, \u201cHierarchical fragmentation in HFS I18308 observed as part of the INFANT survey\u201d, Astronomy & Astrophysics, 2025, 70, A47.
https:\/\/doi.org\/10.1051\/0004-6361\/202554634<\/a><\/p>\n\n\n\n

Corresponding Authors:<\/strong> Y. Cheng, H-L. Liu, X. Lu<\/p>\n","protected":false},"excerpt":{"rendered":"

For decades, formation of high-mass stars exceeding 8 solar masses has remained one of astronomy\u2019s greatest my […]<\/p>\n","protected":false},"author":89,"featured_media":5146,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"cybocfi_hide_featured_image":"yes","_locale":"ja","_original_post":"https:\/\/sci.nao.ac.jp\/main\/?p=5145","footnotes":""},"categories":[23,19],"tags":[],"class_list":["post-5145","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-highlights-en","category-highlights","ja"],"_links":{"self":[{"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/posts\/5145","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/users\/89"}],"replies":[{"embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/comments?post=5145"}],"version-history":[{"count":2,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/posts\/5145\/revisions"}],"predecessor-version":[{"id":5150,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/posts\/5145\/revisions\/5150"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/media\/5146"}],"wp:attachment":[{"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/media?parent=5145"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/categories?post=5145"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sci.nao.ac.jp\/main\/wp-json\/wp\/v2\/tags?post=5145"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}