"Using the metallicities
of the stars in the catalogues from the high quality spectral atlases of APOGEE and LAMOST, and with the distances at which the objects are situated, we have shown that there are an appreciable fraction of stars with higher metallicity, [a] characteristic of disc stars, further out than the previously assumed limit on the radius of the Galaxy disc," study co-author Carlos Allende said in a (https://www.eurekalert.org/pub_releases/2018-06/idad-tdo060718.php) statement.
Villar studies how different amounts of heavy elements, or metallicities
, might alter the detonations.
The process of determining radial velocity dispersions and metallicities
of clusters and galaxies is fundamental to most disciplines of astronomy.
To compare planets by their metallicities
, scientists use the sun as a point of reference -- similar to describing how much caffeine different drinks have by comparing them to a standard cup of coffee.
Reference  found that the metallicities
of half a dozen low-redshift (z < 0.3) LGRB hosts were lower than their equally luminous counterparts in the local star-forming galaxy population and proposed that LGRB formation was limited by a strong metallicity threshold.
(abundances of elements heavier than helium) encountered
Then, they conducted a statistical test to see if the sizes of the planets fell into natural groups, along with the stellar metallicities
For the outer disks of the galaxies, we have found SSP-equivalent metallicities
from the solar one down to [Z/H]=-0.4-0.7, rather high magnesium-to-iron ratios, [Mg/Fe]> +0.2, and mostly old SSP-equivalent ages.
Specific topics covered include the UV spectrum of the galactic bulge, helium and the hot horizontal branch, binary population synthesis and sdB stars at different metallicities
, and hypervelocity stars.
Neptune and Uranus, which are smaller than the gas giants, are richer in heavier elements and have metallicities
about 100 times that of the sun.