Abundance Ratio

Logarithm of the ratio of two metallic elements in a star relative to their ratio in the Sun. This is used to quantify the relative amounts of individual elements present in a star. For example, the abundance ratio of Mg to Fe, written [Mg/Fe], is:

Chemical elements are produced through a variety of processes and abundance ratios contain useful information regarding the source of the gases making up a star. Mg (and other “light” elements such as C and O) are produced in Type II supernovae explosions; “iron peak” elements (Fe, Ni, Zn, Co, Mn, Cr) are produced in Type Ia supernovae explosions. For any given population of stars, the different types of supernovae will explode at different times with the elements produced in the different explosions incorporated into stars at different times.


Some or all content above used with permission from J. H. Wittke.