منابع مشابه
Europium abundances in F and G disk dwarfs ⋆ ⋆ ⋆
Europium abundances for 74 F and G dwarf stars of the galactic disk have been determined from the 4129.7 Å Eu ii line. The stars were selected from the sample of Edvardsson et al. (1993) and [Eu/Fe] shows a smaller scatter and a slightly weaker trend with [Fe/H] than found by Woolf et al. (1995). The data of the two analyses are homogenized and merged. We also discuss the adopted effective temp...
متن کاملLithium abundances in halo dwarfs
The pioneering observations of Spite & Spite showed lithium abundances in halo dwarfs to be almost uniform, irrespective of metallicity and mass over a range of effective temperatures from ∼5600 K up to the main-sequence turnoff. They inferred that the observed abundance was “hardly altered” from that produced in the hot Big Bang. Subsequent efforts have endeavoured to determine how small or la...
متن کاملBeryllium abundances in metal - poor stars ⋆
We have determined beryllium abundances for 25 metal-poor stars based on the high resolution and high signal-to-noise ratio spectra from the VLT/UVES database. Our results confirm that Be abundances increase with Fe, supporting the global enrichment of Be in the Galaxy. Oxygen abundances based on [O i] forbidden line implies a linear relation with a slope close to one for the Be vs. O trend, wh...
متن کاملElement abundances in cool white dwarfs I .
The standard explanation for the presence of photospheric metals in white dwarfs of spectral type DZ and related types is a combination of episodic accretion from the interstellar medium and diffusion of heavy elements downwards in the atmosphere on time scales of typically 106 years. Much of the empirical data on atmospheric parameters and element abundances available in the literature is base...
متن کاملMetal Abundances in Hot DA White Dwarfs
We compare measured element abundances in hot DA white dwarfs from UV observations to predictions from our self-consistent non-LTE model atmosphere diffusion calculations.
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1988
ISSN: 0074-1809
DOI: 10.1017/s0074180900035725