منابع مشابه
Mixing and Accretion in λ Bootis Stars
Strong evidence for deep mixing has been uncovered for slowly rotating F, and A stars of the main sequence. As the accretion/diffusion model for the formation of λ Bootis stars is heavily dependent on mixing in superficial regions, such deep mixing may have important repercussions on our understanding of these stars. It is shown that deep mixing at a level similar to that of FmAm stars increase...
متن کاملOn the Λ Bootis Spectroscopic Binary Hypothesis
Is the proposed spectroscopic binary model able to explain the observed abundance pattern and photometric metallicity indices for the group members? What is the percentage of undetected spectroscopic binary systems? We have used the newest available stellar atmospheres to synthesize 105 hypothetical binary systems in the relevant astrophysical parameter range. These models were used to derive p...
متن کاملHow many λ Bootis stars are binaries ? ?
In the attempt to shed new light on the λ Boo phenomenon we analyzed the astrometric, photometric and spectroscopic characteristics of stars out of a list of recently selected λ Boo candidates. We show that the class is still ill-defined and discuss the possibility that some, if not most stars presently classified as λ Boo, are in fact binary pairs and that peculiar abundances may not correspon...
متن کاملConfirmation of Solar - Like Oscillations in η Bootis
1. Excess power in η Bootis Kjeldsen et al. (1995) detected excess power in the G0 subgiant η Boo from measurements of Balmer-line equivalent widths. The excess was at the expected level, and these authors were able to extract frequency separations and individual frequencies which agreed well with theoretical models (Christensen-Dalsgaard et al., 1995; Guenther & Demarque, 1996). A more detaile...
متن کاملConfirmation of solar-like oscillations in eta Bootis
We obtained time-series spectroscopy of the G0 subgiant η Boo in an attempt to confirm the solar-like oscillations reported by Kjeldsen et al. (1995). We recorded 1843 spectra over six consecutive nights with the Nordic Optical Telescope, which we used to measure equivalent widths of strong temperature-sensitive lines. We also measured velocities from 1989 spectra obtained through an iodine ref...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1875
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.18750862403