منابع مشابه
Evolution of emission line activity in intermediate mass young stars
We present optical spectra of 45 intermediate mass Herbig Ae/Be stars. Together with the multi-epoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by using pre-main sequence evolutionary tracks, we have studied the evolution of emission line activity in them. We find that, on average, the Hα emission line strength decreases...
متن کاملEvolution and Yields of Extremely Metal Poor Intermediate Mass Stars
Intermediate mass stellar evolution tracks from the main sequence to the tip of the AGB for five initial masses (2 to 6M⊙) and metallicity Z=0.0001 have been computed. The detailed 1D structure and evolution models include exponential overshooting, mass loss and a detailed nucleosynthesis network with updated nuclear reaction rates. The network includes a two-particle heavy neutron sink for app...
متن کاملIntermediate Mass Stars: Updated Models
A new set of stellar models in the mass range 1.2 to 9 M⊙ is presented. The adopted chemical compositions cover the typical galactic values, namely 0.0001 ≤ Z ≤ 0.02 and 0.23 ≤ Y ≤ 0.28. A comparison among the most recent compilations of similar stellar models is also discussed. The main conclusion is that the differencies among the various evolutionary results are still rather large. For examp...
متن کاملNucleosynthesis in Intermediate Mass Stars
We discuss nucleosynthesis within 6 M models with Z = 0:02, 0:008 and 0:004. The emphasis is on the AGB phase of evolution, with particular reference to thermal pulses and Hot Bottom Burning. We nd strong CN cycling, with substantial Al production, especially at low metallicities.
متن کاملNew theoretical yields of intermediate mass stars
We present theoretical yields of H, 16 O for stars with initial masses between 0.8 and 8 M ⊙ and initial metallicities Z = 0.001, 0.004, 0.008, 0.02, and 0.04. We use the evolutionary tracks of the Geneva group up to the early asymptotic giant branch (AGB) in combination with a synthetic thermal-pulsing AGB evolution model to follow in detail the chemical evolution and mass loss up to the end o...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1997
ISSN: 0074-1809
DOI: 10.1017/s0074180900116845