Metal Enrichment in the Early Galactic Halo
نویسندگان
چکیده
منابع مشابه
Metal Enrichment in Galactic Winds
Observations give evidences of the presence of metals in the intergalactic medium (IGM). The stars responsible for transforming hydrogen and helium into more complex atoms do not form outside the galaxies in the standard scenario of galaxy formation. Supernovae– driven winds and their associated feedback was proposed as a possible solution to explain such enrichment of the IGM. It turned out th...
متن کاملThe first Galactic stars and chemical enrichment in the halo
The cosmic microwave background and the cosmic expansion can be interpreted as evidence that the Universe underwent an extremely hot and dense phase about 14 Gyr ago. The nucleosynthesis computations tell us that the Universe emerged from this state with a very simple chemical composition: H, H, He, He, and traces of Li. All other nuclei where synthesised at later times. Our stellar evolution m...
متن کاملEnrichment of lead ( Pb ) in the Galactic halo ∗
We have determined lead (Pb) abundances for twelve red giants having [Fe/H] between −2.1 and −1.3, and its upper-limits for two lower metallicity objects, as well as the abundances of lanthanum (La) and europium (Eu). The averages of [Pb/Fe] and [Pb/Eu] are −0.3 and −0.6, respectively, and no clear increase of these ratios with increasing metallicity is found. The [La/Eu] values are only slight...
متن کاملNew Extremely Metal-Poor Stars in the Galactic Halo
We present a detailed abundance analysis based on high resolution and high signal-to-noise spectra of eight extremely metal poor (EMP) stars with [Fe/H] . −3.5 dex, four of which are new. Only stars with 4900 < Teff < 5650 K are included. Two stars of the eight are outliers in each of several abundance ratios. The most metal poor star in this sample, HE1424−0241, has [Fe/H] ∼ −4 dex and is thus...
متن کاملMining the Galactic Halo for Very Metal-Poor Stars
We study the age and metallicity distribution function (MDF) of metal-poor stars in the Milky Way halo as a function of galactocentric radius by combining N-body simulations and semi-analytical methods. We find that the oldest stars populate the innermost region, while extremely metal-poor stars are more concentrated within r < 60 kpc. We predict that the MDF of [Fe/H]≤ −2 stars varies only ver...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Publications of the Astronomical Society of Japan
سال: 1999
ISSN: 0004-6264,2053-051X
DOI: 10.1093/pasj/51.4.459