银河系化学元素的丰度特征和合成图像(I):星际介质中轻元素丰度的观测及其特征

Abundance Characteristic and Synthesis Senario of the GalacticChemical Elements (Ⅰ): Light Element Abundances Characteristicin the Interstellar Medium

给出并解释了星际介质中轻元素D，3He，4He和Li的最新观测数据．星际介质中轻元素的丰度观测结果可以用来检验标准大爆炸核合成理论，因此对这些元素的丰度研究具有重要的天体物理意义．到目前为止，轻元素丰度的观测结果基本上支持开放宇宙的观点．根据最新的观测结果，在本地星际介质中D丰度可能存在小尺度不均匀性，而对类星体吸收云的观测表明不同观测者所获得的原初D丰度结果最大差别可达一个量级．如果观测是可靠的，那么在目前的标准大爆炸核合成理论和星系化学演化模型框架下还不能解释这种结果．另外种种迹象表明太阳系丰度可能不代表45亿年前本地星际介质的丰度．

In this paper, the most recent observational data of the light element abundances in the interstellar medium (ISM) and their interpretations are presented. The abundance of light elementsin the ISM serves as a sensitive diagnostic of the Standard Big Bang Nucleosynthesis (SBBN),therefore they have great astrophysical significance. The light element abundances available noware generally in consistence with the SBBN, which may indicate an open universe. Recent observations have suggested the possible variations of D/H ratios in the local ISM. While the observedresults of the deuterium abundance from high redshifts absorbers towards quasars show largedifference (up to a factor of 10 ) between various measurements, which cannot be properly understood under the framework of current SBBN and galactic chemical evolution theory if theobservations are reliable. Evidences also show that the solar system abundances may not bestrictly representative of the local ISM 4.5 Gyr ago.