Abundances in extragalactic HII regions

We determine the primordial helium mass fraction Yp using 93 spectra of 86 low-metallicity extragalactic HII regions. This sample constitutes the largest and most homogeneous...本研究利用86个低金属丰度河外HII区（extragalactic HII regions）的93条光谱，测定了原初氦质量分数Yp（primordial helium mass fraction Yp）。该样本是迄今规模最大且均一性最强的……