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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Prevalence of SED Turndown among Classical Be Stars: Are All Be Stars Close Binaries?

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Klement, Robert [1] ; Carciofi, A. C. [2] ; Rivinius, T. [3] ; Ignace, R. [4] ; Matthews, L. D. [5] ; Torstensson, K. [3] ; Gies, D. [6, 7] ; Vieira, R. G. [2] ; Richardson, N. D. [8] ; de Souza, A. Domiciano [9] ; Bjorkman, J. E. [8] ; Hallinan, G. [10] ; Faes, D. M. [2] ; Mota, B. [2] ; Gullingsrud, A. D. [8] ; de Breuck, C. [11] ; Kervella, P. [12] ; Cure, M. [13] ; Gunawan, D. [13]
Total Authors: 19
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[1] CHARA Array Georgia State Univ, Mt Wilson Observ, Mt Wilson, CA 91023 - USA
[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil
[3] European Southern Observ, Alonso de Cordova 3107, Casilla 19001, Santiago - Chile
[4] East Tennessee State Univ, Dept Phys & Astron, Johnson City, TN 37614 - USA
[5] MIT, Haystack Observ, 99 Millstone Rd, Westford, MA 01886 - USA
[6] Georgia State Univ, Ctr High Angular Resolut Astron, POB 5060, Atlanta, GA 30302 - USA
[7] Georgia State Univ, Dept Phys & Astron, POB 5060, Atlanta, GA 30302 - USA
[8] Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 - USA
[9] Univ Cote Azur, Observ Cote Azur, CNRS, UMR7293 Lagrange, 28 Av Valrose, F-06108 Nice 2 - France
[10] CALTECH, Cahill Ctr Astrophys, 1200 E Calif Blvd, MC 249-17, Pasadena, CA 91125 - USA
[11] European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching - Germany
[12] Sorbonne Univ, Univ Paris Diderot, Sorbonne Paris Cite, LESIA, Observ Paris, Univ PSL, CNRS, 5 Pl JulesJanssen, F-92195 Meudon - France
[13] Univ Valparaiso, Fac Ciencias, Inst Fis & Astron, Casilla 5030, Valparaiso - Chile
Total Affiliations: 13
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL; v. 885, n. 2 NOV 10 2019.
Web of Science Citations: 1

Rapid rotation is a fundamental characteristic of classical Be stars and a crucial property allowing for the formation of their circumstellar disks. Past evolution in a mass and angular momentum transferring binary system offers a plausible solution to how Be stars attained their fast rotation. Although the subdwarf remnants of mass donors in such systems should exist in abundance, only a few have been confirmed due to tight observational constraints. An indirect method of detecting otherwise hidden companions is offered by their effect on the outer parts of Be star disks, which are expected to be disrupted or truncated. In the context of the infrared and radio continuum excess radiation originating in the disk, the disk truncation can be revealed by a turndown in the spectral energy distribution due to reduced radio flux levels. In this work, we search for signs of spectral turndown in a sample of 57 classical Be stars with radio data, which include new data for 23 stars and the longest-wavelength detections so far (?10 cm) for two stars. We confidently detect the turndown for all 26 stars with sufficient data coverage (20 of which are not known to have close binary companions). For the remaining 31 stars, the data are inconclusive as to whether the turndown is present or not. The analysis suggests that many if not all Be stars have close companions influencing their outer disks. If confirmed to be subdwarf companions, the mass transfer spin-up scenario might explain the existence of the vast majority of classical Be stars. (AU)

FAPESP's process: 16/16844-1 - Systems Engineering for GMACS: GMT AT-13 Project
Grantee:Daniel Moser Faes
Support type: Scholarships in Brazil - Post-Doctorate