The structural stratification of a solar-type main sequence star primarily depends on its mass and chemical composition .
The surface heavy element abundances of the solar-type stars are reasonably well determined using conventional spectroscopy , however the second most abundant element helium is not .
This is due to the fact that the envelope temperature of such stars is not high enough to excite helium .
Since the helium abundance of a star affects its structure and subsequent evolution , the uncertainty in the helium abundance of a star makes estimates of its global properties ( mass , radius , age etc . )
uncertain as well .
The detections of the signatures of the acoustic glitches from the precisely measured stellar oscillation frequencies provide an indirect way to estimate the envelope helium content .
We use the glitch signature caused by the ionization of helium to determine the envelope helium abundance of 38 stars in the Kepler seismic LEGACY sample .
Our results confirm that atomic diffusion does indeed take place in solar-type stars .
We use the measured surface abundances in combination with the settling predicted by the stellar models to determine the initial abundances .
The initial helium and metal mass fractions have subsequently been used to get the preliminary estimates of the primordial helium abundance , Y _ { p } = 0.244 \pm 0.019 , and the galactic enrichment ratio , \Delta Y / \Delta Z = 1.226 \pm 0.849 .
Although the current estimates have large errorbars due to the limited sample size , this method holds great promises to determine these parameters precisely in the era of upcoming space missions .