Variations of the mixing character of dipolar mixed modes in red giant stars

• Tipo: Artigo em Revista Científica Internacional
• Data: 2020

Autores

Jiang, C (Autor) Outra; Cunha, MS (Autor) FCUP; Christensen Dalsgaard, J (Autor) Outra; Zhang, QS (Autor) Outra

Revista

Título: Monthly Notices of the Royal Astronomical Society

Vol. 495

Páginas: 621-636

ISSN: 0035-8711

Editora: Oxford University Press

Indexação

ISI Web of Knowledge - 0 Citações

Outras Informações

ID Authenticus: P-00S-A8Y

DOI: 10.1093/mnras/staa1285

Abstract (EN): Because of the high-quality data of space missions, the detection of mixed modes has become possible in numerous stars. In this work, we investigate how the mixing character of dipolar mixed modes changes with stellar evolution, as well as with frequency within each stellar model. This is achieved by monitoring the variations in the coupling strength and the period spacing of dipolar mixed modes in red-giant models. These parameters are measured by fitting the asymptotic expansion of mixed modes to the model frequencies of a grid of red-giant models with masses between 1.0 and 2.0 M-circle dot and three different chemical abundances. The coupling strength and the period spacing decrease with stellar evolution. We find that the slopes of their decreasing trends depend on the radial order of the pressure mode component. A non-negligible increase of the coupling strength with frequency by up to around 40 per cent is found in the observable frequency range for a set of red-giant models. On the contrary, no significant changes of the period spacing with frequency are found. The changes in the mixing character of the modes are in most cases affected by the model mass and metallicity. Buoyancy glitches also have an impact on the mixing character. Significant fluctuations in the estimated coupling strength and period spacing are found for models approaching the luminosity bump, if the glitch impact of the frequencies is not considered in the applied asymptotic expansion.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 16