metallicity

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metallicity

(met-ă-liss -ă-tee) (metal abundance) Symbol: Z . The fraction by mass of metals in a star, cluster of stars, or in some other astronomical entity. Since metals are produced by nucleosynthesis in stars, the metallicity of an object or class of objects depends on when it was formed: objects of later origin in general have a higher metallicity. Metallicity is determined by photometry or high-resolution spectroscopy, and is usually expressed relative to solar metallicity (see cosmic abundance), and as the ratio of iron to hydrogen, Fe/H. See also population I, population II.
References in periodicals archive ?
The infrared capabilities of WFC3 have allowed astronomers to finally calculate how much these low-mass dwarf galaxies contributed to the star population in our universe.
We chose three of the five exposed sites for long-term surveys of prey abundance and sea star population structure.
In addition, B2 0902+34 has a somewhat younger star population and a blobby, less elongated shape.
The team accounted for this, and was able to show that the velocity dispersion or random motion of the RR Lyrae star population was very high relative to the other stars in the Milky Way's center.
As the last generation of massive and brilliant, but short-lived, blue stars dies out, the long-lived, lower mass, redder stars come to dominate the merger's star population, giving the gas-starved galaxy an overall reddish hue over time.
Manchester says the relatively large number of millisecond pulsars in 47 Tucanae suggests that the ancient cluster began with a star population more massive than previously thought.
"We've detected the brightest X-ray flare yet observed from Sgr A* and gathered data that are causing us to overhaul of our understanding of the neutron star population in the galactic center." Ee Ee Ee
Then, they took traces of chemical elements found in the light from ancient binary star populations as well as their evolutionary processes into account to run the model. 
"Ultraviolet light is a major tracer of the youngest and hottest star populations, which astronomers need to derive the ages of stars and get a complete stellar history.
IT HAS NOW BEEN THREE YEARS since the initial detection of sea star wasting disease, and most of the decimated sea star populations have yet to recover to anything approaching their former numbers.
As signaled by the subtitle, this manifestation of the conference focuses on complex atmospheres, binarity, dust, the cosmic matter cycle, external asymptotic giant branch (AGB) star populations, and perspectives arising from new instrumentation.
Incipient speciation of sea star populations by adaptive gamete recognition coevolution.