Evidence for reduced magnetic braking in polars from binary population models

Autor(es)

Belloni, Diogo ^{[1, 2]} ; Schreiber, Matthias R. ^{[1, 3]} ; Pala, Anna F. ^[4] ; Gansicke, Boris T. ^[5] ; Zorotovic, Monica ^[1] ; Rodrigues, V, Claudia

Afiliação do(s) autor(es)

^[1] Univ Valparaiso, Inst Fis & Astron, Av Gran Bretana 1111, Valparaiso 2360102 - Chile

^[2] V, Natl Inst Space Res, Av Astronautas 1758, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[3] Univ Valparaiso, Millenium Nucleus Planet Format, Valparaiso 2360102 - Chile

^[4] European Southern Observ, Karl Schwarzschild Str 2, D-85748 Garching - Germany

^[5] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands - England

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 491, n. 4, p. 5717-5731, FEB 2020.
• Citações Web of Science: 1

Resumo

We present the first population synthesis of synchronous magnetic cataclysmic variables, called polars, taking into account the effect of the white dwarf (WD) magnetic field on angular momentum loss. We implemented the reduced magnetic braking (MB) model proposed by Li, Wu \& Wickramasinghe into the Binary Stellar Evolution (BSE) code recently calibrated for cataclysmic variable (CV) evolution. We then compared separately our predictions for polars and non-magnetic CVs with a large and homogeneous sample of observed CVs from the Sloan Digital Sky Survey. We found that the predicted orbital period distributions and space densities agree with the observations if period bouncers are excluded. For polars, we also find agreement between predicted and observed mass transfer rates, while the mass transfer rates of non-magnetic CVs with periods greater than or similar to 3 h drastically disagree with those derived from observations. Our results provide strong evidence that the reduced MB model for the evolution of highly magnetized accreting WDs can explain the observed properties of polars. The remaining main issues in our understanding of CV evolution are the origin of the large number of highly magnetic WDs, the large scatter of the observed mass transfer rates for non-magnetic systems with periods greater than or similar to 3 h, and the absence of period bouncers in observed samples. (AU)

• Processo FAPESP: 17/14289-3 - Variáveis cataclísmicas magnéticas: evolução secular com o código BSE e modelagem de emissão com o código CYCLOPS
• Beneficiário: Diogo Teixeira Belloni
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/26258-4 - Matéria superdensa no universo
• Beneficiário: Manuel Máximo Bastos Malheiro de Oliveira
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 18/23562-8 - Investigando a origem de supernovas do Tipo Ia com o código BSE
• Beneficiário: Diogo Teixeira Belloni
• Linha de fomento: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado