Iron elemental abundances

Titanium is the ninth most abundant element ia the earth s cmst, at approximately 0.62%, and the fourth most abundant stmctural element. Its elemental abundance is about five times less than iron and 100 times greater than copper, yet for stmctural appHcations titanium s aimual use is ca 200 times less than copper and 2000 times less than iron. Metal production began in 1948 its principal use was in military aircraft. Gradually the appHcations spread to commercial aircraft, the chemical industry, and, more recently, consumer goods. 

By comparing the observed chemical abundance ratios to supernova model yields, one can calculate , the ratio of the number of SNe la to SNe II events that fit the observations and the synthesized mass of the elements from the model yields. In a study adopting the same analysis techniques as those performed here, [5] found large values of for a trio of low-a stars of [Fe/H] -2. Employing the abundances derived in this study of stars with comparable metallicities, I find that the metal-poor systems presented here possess a- and iron-peak abundances (and based on Na, Mg, Si and Fe) consistent with those observed in metal-poor stars of the MWG (e.g., [6]). 

For the Sgr dSph we present the UVES DIC1 spectra for 12 giants. Complete analysis of two of them has already been published [2], while for the other ten only iron and a-elements abundances have been published so far (see [3]). Details on the reduction and analysis procedures, and physical parameters for the stars are provided in [3], but they can be briefly resumed here the spectra have been analyzed by means of LTE, one dimensional atmosphere models, using ATLAS, WIDTH and SYNTHE codes (see [7] and [10]). Te// for the stars are in the range 4800 - 5050 K, log g between 2.3 and 2.7. We analyzed abundances of proton capture (Na, Al, Sc, V), a (Mg, Si, Ca, Ti), Iron-peak (Cr, Fe, Co, Ni, Zn) and heavy neutron-capture (Y, La, Ce, Nd) elements. 

Abstract. We present preliminary iron abundances and a element (Ca, Mg) abundance ratios for a sample of 22 Red Giant Branch (RGB) Stars in the Sagittarius galaxy (Sgr), selected near the RGB-Tip. The sample is representative of the Sgr dominant population. The mean iron abundance is [Fe/H]=-0.49. The a element abundance ratios are slightly subsolar, in agreement with the results recently presented by [2]. 

Fig. 1. Upper panel metallicity distribution for the 22 stars analyzed so far. Lower panel a element abundance ratio vs iron abundance for 20 stars of the sample. The [a/Fe] abundance ratio is the average of [Mg/Fe] and [Ca/Fe]. A typical errorbar is also plotted.

A library of stellar spectra or absorption-line strengths, taking into account differences in a-element iron and possibly other element abundance ratios. The spectra may be either observational or synthetic, i.e. theoretically computed. 

Iron, element 26 in the periodic table, is the fourth most abundant element of the earth s crust and, after aluminium, the second most abundant metal. In the middle of the first transition... 

The isotopic and elemental abundance table shows that, in the Solar System, iron is more abundant than its neighbours. Analysis of stellar spectra conhrms this result, giving it a universal character. 

Iron meteorites offer the unique opportunity to examine metallic cores from deep within differentiated bodies. Most of these samples were exposed and dislodged when asteroids collided and fragmented. Although irons constitute only about 6% of meteorite falls, they are well represented in museum collections. Most iron meteorites show wide variations in siderophile-element abundances, which can be explained by processes like fractional crystallization in cores that mimic those in achondrites. However, some show perplexing chemical trends that may be inconsistent with their formation as asteroid cores. 

Elemental abundances in group IIIAB iron meteorites (dots) compared to calculated fractional crystallization trends that assume complete separation of crystals and melt (solid curve) and incomplete separation of those phases (dashed curve). Modified from Haack and McCoy (2004). 

The Mars Pathfinder rover carried an Alpha Proton X-ray Spectrometer (APXS), and the two Mars Exploration Rovers (MER - Spirit and Opportunity) carried Alpha Particle X-ray Spectrometers (also called APXS, but in this case more precise versions of the Pathfinder instrument, though without the ability to monitor protons for light element analyses). These instruments contained radioactive curium sources (Fig. 13.16) whose decay produced a-particles, which irradiated target rocks and soils. The resulting characteristic X-rays provided measurements of major and minor element abundances. The MER rovers also carried Mossbauer spectrometers, which yielded information on iron oxidation state. 

The fascination with the abundances of the atomic nuclei is that they inform of ancient events. The events that are recorded in their populations depend upon the material sample in question. In the crust of the Earth, they record its geologic evolution. Silicon in that crust is much more abundant than iron, for example, because the Earth s crust is sandy, whereas its iron sank to the Earth s core during its early molten state. In the Earth s oceans the elemental abundances reflect their solubilities in water. In the Earth s atmosphere, their numbers reflect their volatilities. And so it goes. Such abundance-sets reflect and record the geophysical history of the Earth and the chemical properties of the chemical elements. Atmospheric carbon dioxide (C02) and methane (CH4) record an extra wrinkle, the impact of human beings on the Earth s atmosphere. 

Lithium is not an abundant element, only 29th in rank of all element abundances, so that 6Li is one of the least abundant nuclear species lighter than iron. Only 9Be is less abundant than 6Li and the comparably rare 10B among the light nuclei. These are such low-abundance isotopes that their processes of nucleosynthesis must be rare or very inefficient. 

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