Scalar Field Gravastars: Derivation of Junction Conditions, Shell Stability, and Gravitational Wave Signatures

Scalar Field Gravastars: Derivation of Junction Conditions, Shell Stability, and Gravitational Wave Signatures | 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 Research Article Scalar Field Gravastars: Derivation of Junction Conditions, Shell Stability, and Gravitational Wave Signatures Chaitanya Sihare This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9294914/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 The gravastar model requires, as an external postulate, a thin shell of zero surface energy density separating a de Sitter interior from a Schwarzschild exterior. We show that this condition is not an assumption but a derived result when the interior is sourced by a static, spherically symmetric scalar field. Starting from the exact identity ρ + 3P = −2V (ϕ), we establish that any non-negative scalar potential enforces Strong Energy Condition violation throughout the interior. The regularity condition ∂rϕ|r=0 = 0 forces w = −1 at the core and the de Sitter geometry follows from the Einstein equations without additional postulate. Applying the Israel junction formalism, we prove that the mass relation M = 4π 3 V0R3 enforced by the scalar Einstein equations implies vanishing surface energy density σ = 0 at the unique equilibrium radius determined by the scalar field dynamics. The shell is radially stable and non-radially stable with surface sound speed c 2 s > 0, subject to the causality constraint. The physical parameter window 16/(243πM2 ) < V0 < 3/(32πM2 ) gives configurations more compact than any Buchdahl perfectfluid star and outside the Schwarzschild radius. The tidal Love number k2 < 0 throughout the physical parameter space, giving a negative tidal deformability Λ 0), and scalar gravastars (Λ < 0), testable by the Einstein Telescope. All results are confirmed by numerical solution of the full coupled TOV+Klein-Gordon system. PACS: 04.70.Bw, 04.30.Db, 04.40.Dg Theoretical Physics High Energy and Particle Physics Astrophysics and Cosmology gravastar scalar field Strong Energy Condition Israel junction conditions tidal deformability gravitational waves quasinormal modes Full Text Additional Declarations The authors declare no competing interests. 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-9294914","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":616127682,"identity":"363ebd36-b522-41b2-b30b-2dcfbb7741d0","order_by":0,"name":"Chaitanya Sihare","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0000-0340-2492","institution":"PG college","correspondingAuthor":true,"prefix":"","firstName":"Chaitanya","middleName":"","lastName":"Sihare","suffix":""}],"badges":[],"createdAt":"2026-04-01 17:42:07","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9294914/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9294914/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106094838,"identity":"bf90b328-3af2-416a-a4a7-7c0742e0a3e1","added_by":"auto","created_at":"2026-04-03 11:43:23","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":803643,"visible":true,"origin":"","legend":"","description":"","filename":"SCPMA20260330RevisedManuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9294914/v1_covered_d83c3641-98ba-48a7-80c6-e779ed3141fd.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eScalar Field Gravastars: Derivation of Junction Conditions, Shell Stability, and Gravitational Wave Signatures\u003c/p\u003e","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":true,"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 Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"gravastar, scalar field, Strong Energy Condition, Israel junction conditions, tidal deformability, gravitational waves, quasinormal modes","lastPublishedDoi":"10.21203/rs.3.rs-9294914/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9294914/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe gravastar model requires, as an external postulate, a thin shell of zero surface energy density separating a de Sitter interior from a Schwarzschild exterior. We show that this condition is not an assumption but a derived result when the interior is sourced by a static, spherically symmetric scalar field. Starting from the exact identity ρ + 3P = −2V (ϕ), we establish that any non-negative scalar potential enforces Strong Energy Condition violation throughout the interior. The regularity condition ∂rϕ|r=0 = 0 forces w = −1 at the core and the de Sitter geometry follows from the Einstein equations without additional postulate. Applying the Israel junction formalism, we prove that the mass relation M = 4π 3 V0R3 enforced by the scalar Einstein equations implies vanishing surface energy density σ = 0 at the unique equilibrium radius determined by the scalar field dynamics. The shell is radially stable and non-radially stable with surface sound speed c 2 s \u0026gt; 0, subject to the causality constraint. The physical parameter window 16/(243πM2 ) \u0026lt; V0 \u0026lt; 3/(32πM2 ) gives configurations more compact than any Buchdahl perfectfluid star and outside the Schwarzschild radius. The tidal Love number k2 \u0026lt; 0 throughout the physical parameter space, giving a negative tidal deformability Λ \u0026lt; 0 — an anti-tidal response unique to objects with repulsive de Sitter interiors, providing a three-way discriminant among black holes (Λ = 0), neutron stars (Λ \u0026gt; 0), and scalar gravastars (Λ \u0026lt; 0), testable by the Einstein Telescope. All results are confirmed by numerical solution of the full coupled TOV+Klein-Gordon system.\u003c/p\u003e\n\u003cp\u003ePACS: 04.70.Bw, 04.30.Db, 04.40.Dg\u003c/p\u003e","manuscriptTitle":"Scalar Field Gravastars: Derivation of Junction Conditions, Shell Stability, and Gravitational Wave Signatures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-03 05:00:35","doi":"10.21203/rs.3.rs-9294914/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":"6379af41-395d-4a40-8e90-3c39b54a50b8","owner":[],"postedDate":"April 3rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":65565342,"name":"Theoretical Physics"},{"id":65565343,"name":"High Energy and Particle Physics"},{"id":65565344,"name":"Astrophysics and Cosmology"}],"tags":[],"updatedAt":"2026-04-03T05:00:35+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-03 05:00:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9294914","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9294914","identity":"rs-9294914","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}