Poster abstract details
Evolutionary Scenarios and Chemical Inhomogeneities of Extended Horizontal Branch Stars
Abstract
Extended Horizontal Branch (EHB) stars are observed in many
globular clusters and as field stars in the Galactic halo. They
belong to old stellar populations of the halo and the old disk.
Their evolutionary status is unclear, and still a current subject of
debate. Current interest in these stars arise from their
association with the discoveries of helium abundance inhomogeneities
in the globular clusters $\omega$ Cen and NGC 2808. The origin of
the inhomogeneities is not yet understood, but there are
many interpretations.
In order to better understand EHB stars, we explore the evolution of standard blue HB models using up-to-date physics. We present several grids of post-ZAHB evolutionary models to include both canonical and non-canonical evolutionary scenarios, as well as to compare models that contain semi-convection to models
without semi-convection. We follow the models to the termination of nuclear helium burning. The detailed properties of the models, including shell flashes and breathing pulses, are described.
globular clusters and as field stars in the Galactic halo. They
belong to old stellar populations of the halo and the old disk.
Their evolutionary status is unclear, and still a current subject of
debate. Current interest in these stars arise from their
association with the discoveries of helium abundance inhomogeneities
in the globular clusters $\omega$ Cen and NGC 2808. The origin of
the inhomogeneities is not yet understood, but there are
many interpretations.
In order to better understand EHB stars, we explore the evolution of standard blue HB models using up-to-date physics. We present several grids of post-ZAHB evolutionary models to include both canonical and non-canonical evolutionary scenarios, as well as to compare models that contain semi-convection to models
without semi-convection. We follow the models to the termination of nuclear helium burning. The detailed properties of the models, including shell flashes and breathing pulses, are described.