Massive star cluster seeds form by gravo-turbulent flows rather than magnetized collapse

Massive star cluster seeds form by gravo-turbulent flows rather than magnetized collapse | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Physical Sciences - Article Massive star cluster seeds form by gravo-turbulent flows rather than magnetized collapse Junhao Liu, Patricio Sanhueza, Piyali Saha, Kaho Morii, Anaelle Maury, and 31 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6746342/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract High-mass stars form in protoclusters, where gravo-magnetic processes shape massive star-forming clouds and clumps to be elongated preferentially perpendicular to magnetic fields. Yet it remains unclear whether magnetic fields still govern the formation of smaller-scale ($\sim$1000 au) condensations in massive protoclusters, which are crucial for understanding the stellar initial mass function and multiplicity. Here we report the first statistical evidence that the condensation elongation exhibits a preferentially more parallel alignment with magnetic fields at $\sim$1000 au scales, based on high-resolution data from the largest dust polarization survey toward 30 massive star-forming regions with the Atacama Large Millimeter/submillimeter Array (ALMA). Our clustered massive star formation simulations reveal that this more parallel alignment is exclusively observed in initially super-Alfv'{e}nic (turbulence dominates magnetic fields) models. In contrast, initially sub-Alfv'{e}nic (magnetic fields dominate turbulence) models distinctly exhibit a more perpendicular alignment. These findings offer compelling statistical evidence that the formation of small-scale condensations is governed by turbulence rather than magnetic fields in the context of clustered massive star formation, contradicting the prediction of classical magnetically regulated models. Moreover, turbulence imposes a preferential misalignment between the magnetic field and rotation axis of condensations, which can potentially reduce the magnetic braking efficiency, facilitate the formation of large protostellar disks, and allow disk fragmentation to occur. Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Interstellar medium Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Astrophysical magnetic fields Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6746342","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":465161377,"identity":"09737211-6f81-44bb-b222-f9d81c96e72b","order_by":0,"name":"Junhao Liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACxgYGNhAtw8bAfAAmmECUFh42Bja4SvxagACiBYgMiHMY84zcYw9+VDDw8EnkfAMx5PkbGJ49wOuwGXnphj1ngA6TyN0OYhjOOMCQjtc+xhk5ZhK8bWAt20AMxg0MDGkShLRI/gVryXkGYtgTpUUaYksOG4iRSFhLzxszaZkzEjxsPM/AjOQZhwn4xbAd6LA3FTZy8u3Jz0AM2/72nrQHeLU0gCm4S4AMZp40fDoY5LGIsR/Dq2UUjIJRMApGHAAAIg06vbYnEw4AAAAASUVORK5CYII=","orcid":"","institution":"National Astronomical Observatory of Japan","correspondingAuthor":true,"prefix":"","firstName":"Junhao","middleName":"","lastName":"Liu","suffix":""},{"id":465161378,"identity":"2eca1025-ca9a-447f-9132-64dcb08c706d","order_by":1,"name":"Patricio Sanhueza","email":"","orcid":"","institution":"Department of Astronomy, School of Science, The University of Tokyo","correspondingAuthor":false,"prefix":"","firstName":"Patricio","middleName":"","lastName":"Sanhueza","suffix":""},{"id":465161379,"identity":"f5f5ae19-5414-4cab-ad78-327909a49c42","order_by":2,"name":"Piyali Saha","email":"","orcid":"","institution":"Academia Sinica, Institute of Astronomy and Astrophysics","correspondingAuthor":false,"prefix":"","firstName":"Piyali","middleName":"","lastName":"Saha","suffix":""},{"id":465161380,"identity":"4e176e50-57de-4697-b5d7-c01e57466f7d","order_by":3,"name":"Kaho Morii","email":"","orcid":"","institution":"Center for Astrophysics | Harvard \u0026 Smithsonian","correspondingAuthor":false,"prefix":"","firstName":"Kaho","middleName":"","lastName":"Morii","suffix":""},{"id":465161381,"identity":"c6a7fb9b-aa9d-4e9f-bf0f-b599fb2b8059","order_by":4,"name":"Anaelle Maury","email":"","orcid":"","institution":"Institut de Ciencies de l'Espai (ICE, CSIC)","correspondingAuthor":false,"prefix":"","firstName":"Anaelle","middleName":"","lastName":"Maury","suffix":""},{"id":465161382,"identity":"2964c448-02c3-4e01-9420-a7bc2f7cc251","order_by":5,"name":"Josep Miquel Girart","email":"","orcid":"","institution":"Institut de Cie`ncies de I’Espai (ICE-CSIC)","correspondingAuthor":false,"prefix":"","firstName":"Josep","middleName":"Miquel","lastName":"Girart","suffix":""},{"id":465161383,"identity":"e8ae82bf-b193-45b2-8c28-3719a785d83a","order_by":6,"name":"Qizhou Zhang","email":"","orcid":"https://orcid.org/0000-0003-2384-6589","institution":"Center for Astrophysics | Harvard \u0026 Smithsonian","correspondingAuthor":false,"prefix":"","firstName":"Qizhou","middleName":"","lastName":"Zhang","suffix":""},{"id":465161384,"identity":"1a28c00c-04d4-4333-9057-64662150c472","order_by":7,"name":"Fumitaka Nakamura","email":"","orcid":"https://orcid.org/0000-0001-5431-2294","institution":"National Astronomical Observatory of Japan","correspondingAuthor":false,"prefix":"","firstName":"Fumitaka","middleName":"","lastName":"Nakamura","suffix":""},{"id":465161385,"identity":"90b5219b-8eb0-44f4-92ce-f1c649e66475","order_by":8,"name":"Paulo Cortés","email":"","orcid":"","institution":"ALMA","correspondingAuthor":false,"prefix":"","firstName":"Paulo","middleName":"","lastName":"Cortés","suffix":""},{"id":465161386,"identity":"f6236951-bb56-4e4f-ae4c-e44499a7da91","order_by":9,"name":"Valeska Valdivia","email":"","orcid":"","institution":"Nagoya University","correspondingAuthor":false,"prefix":"","firstName":"Valeska","middleName":"","lastName":"Valdivia","suffix":""},{"id":465161387,"identity":"5a5b8eee-65e6-445b-a157-453b501bdc9c","order_by":10,"name":"Benoit Commercon","email":"","orcid":"","institution":"Univ. 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collapse","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research 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Yet it remains unclear whether magnetic fields still govern the formation of smaller-scale ($\\sim$1000 au) condensations in massive protoclusters, which are crucial for understanding the stellar initial mass function and multiplicity. \r\nHere we report the first statistical evidence that the condensation elongation exhibits a preferentially more parallel alignment with magnetic fields at $\\sim$1000 au scales, based on high-resolution data from the largest dust polarization survey toward 30 massive star-forming regions with the Atacama Large Millimeter/submillimeter Array (ALMA). Our clustered massive star formation simulations reveal that this more parallel alignment is exclusively observed in initially super-Alfv\\'{e}nic (turbulence dominates magnetic fields) models. In contrast, initially sub-Alfv\\'{e}nic (magnetic fields dominate turbulence) models distinctly exhibit a more perpendicular alignment. \r\nThese findings offer compelling statistical evidence that the formation of small-scale condensations is governed by turbulence rather than magnetic fields in the context of clustered massive star formation, contradicting the prediction of classical magnetically regulated models. Moreover, turbulence imposes a preferential misalignment between the magnetic field and rotation axis of condensations, which can potentially reduce the magnetic braking efficiency, facilitate the formation of large protostellar disks, and allow disk fragmentation to occur.","manuscriptTitle":"Massive star cluster seeds form by gravo-turbulent flows rather than magnetized collapse","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-03 17:24:57","doi":"10.21203/rs.3.rs-6746342/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ff7587bb-1fca-4381-b2f1-89abb737622d","owner":[],"postedDate":"June 3rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":49378144,"name":"Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Interstellar medium"},{"id":49378145,"name":"Physical sciences/Astronomy and planetary science/Astronomy and astrophysics/Astrophysical magnetic fields"}],"tags":[],"updatedAt":"2025-07-21T12:20:43+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-03 17:24:57","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6746342","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6746342","identity":"rs-6746342","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}