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(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: time-dependent modelling of infrared continuum observations

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Autor(es):
Vieira, R. G. ; Carciofi, A. C. ; Bjorkman, J. E. ; Rivinius, Th. ; Baade, D. ; Rimulo, L. R.
Número total de Autores: 6
Tipo de documento: Artigo Científico
Fonte: Monthly Notices of the Royal Astronomical Society; v. 464, n. 3, p. 3071-3089, JAN 2017.
Citações Web of Science: 19
Resumo

We apply the viscous decretion disc (VDD) model to interpret the infrared disc continuum emission of 80 Be stars observed in different epochs. In this way, we determined 169 specific disc structures, namely their density scale, rho 0, and exponent, n. We found that the n values range mainly between 1.5 and 3.5, and rho 0 varies between 10(-12) and 10(-10) g cm(-3), with a peak close to the lower value. Our large sample also allowed us to firmly establish that the discs around early-type stars are denser than in late-type stars. Additionally, we estimated the disc mass decretion rates and found that they range between 10(-12) and 10(-9)M(circle dot)yr(-1). These values are compatible with recent stellar evolution models of fast-rotating stars. One of the main findings of this work is a correlation between the rho 0 and n values. In order to find out whether these relations can be traced back to the evolution of discs or have some other origin, we used the VDD model to calculate temporal sequences under different assumptions for the time profile of the disc mass injection. The results support the hypothesis that the observed distribution of disc properties is due to a common evolutionary path. In particular, our results suggest that the time-scale for disc growth, during which the disc is being actively fed by mass injection episodes, is shorter than the time-scale for disc dissipation, when the disc is no longer fed by the star and dissipates as a result of the viscous diffusion of the disc material. (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: 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