Busca avançada
Ano de início
Entree
(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

The life cycles of Be viscous decretion discs: fundamental disc parameters of 54 SMC Be stars

Texto completo
Autor(es):
Rimulo, L. R. [1] ; Carciofi, A. C. [1] ; Vieira, R. G. [1] ; Rivinius, Th. [2] ; Faes, D. M. [1] ; Figueiredo, A. L. [1] ; Bjorkman, J. E. [3] ; Georgy, C. [4] ; Ghoreyshi, M. R. [1] ; Soszynski, I. [5]
Número total de Autores: 10
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil
[2] European Southern Observ, Alonso de Cordova 3107, Casilla 19001, Santiago 19 - Chile
[3] Univ Toledo, Dept Phys & Astron, Ritter Observ, Mail Stop 113, Toledo, OH 43606 - USA
[4] Observ Geneva, Chemin Maillettes 51, CH-1290 Sauverny, Versoix - Switzerland
[5] Univ Warsaw Observ, Al Ujazdowskie 4, PL-00478 Warsaw - Poland
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: Monthly Notices of the Royal Astronomical Society; v. 476, n. 3, p. 3555-3579, MAY 2018.
Citações Web of Science: 11
Resumo

Be stars are main-sequence massive stars with emission features in their spectrum, which originates in circumstellar gaseous discs. Even though the viscous decretion disc model can satisfactorily explain most observations, two important physical ingredients, namely the magnitude of the viscosity (alpha) and the disc mass injection rate, remain poorly constrained. The light curves of Be stars that undergo events of disc formation and dissipation offer an opportunity to constrain these quantities. A pipeline was developed to model these events that use a grid of synthetic light curves, computed from coupled hydrodynamic and radiative transfer calculations. A sample of 54 Be stars from the OGLE survey of the Small Magellanic Cloud (SMC) was selected for this study. Because of the way our sample was selected (bright stars with clear disc events), it likely represents the densest discs in the SMC. Like their siblings in the Galaxy, the mass of the disc in the SMC increases with the stellar mass. The typical mass and angular momentum loss rates associated with the disc events are of the order of similar to 10(-10) M-circle dot yr(-1) and similar to 5 x 10(36) g cm(2) s(-2), respectively. The values of a found in this work are typically of a few tenths, consistent with recent results in the literature and with the ones found in dwarf novae, but larger than current theory predicts. Considering the sample as a whole, the viscosity parameter is roughly two times larger at build-up (<alpha(bu)> = 0.63) than at dissipation (<alpha(d)> = 0.26). Further work is necessary to verify whether this trend is real or a result of some of the model assumptions. (AU)

Processo FAPESP: 15/17967-7 - Discos de decréscimo viscoso: teoria e observações
Beneficiário:Alex Cavaliéri Carciofi
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 09/54006-4 - Um cluster de computadores para o Departamento de Astronomia do IAG-USP e para o Núcleo de Astrofísica da UNICSUL
Beneficiário:Elisabete Maria de Gouveia Dal Pino
Linha de fomento: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
Processo FAPESP: 16/16844-1 - Engenharia de Sistemas para o GMACS: projeto GMT AT-13
Beneficiário:Daniel Moser Faes
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 12/20364-4 - Além da sobrevivência da poeira: as regiões internas de discos protoplanetários
Beneficiário:Rodrigo Georgetti Vieira
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 12/21518-5 - Estudo da evolução dinâmica de delta Scorpii
Beneficiário:Leandro Rocha Rímulo
Linha de fomento: Bolsas no Brasil - Doutorado