The abundance of sulfur in extragalactic H II regions
The abundance of sulfur in extragalactic H II regions
复制标题
河外H II区域硫丰度
DOI：
10.1086/167904
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
D. Garnett
中科院分区：
文献类型：
--
作者：
D. Garnett
本文介绍了用长缝CCD对河外13个H Ⅱ区的S Ⅲ 9069、9532 A禁戒辐射进行的观测，并利用观测数据研究了S/O随O/H的变化。这些数据与当O/H变化时S/O保持不变的观点是一致的。没有证据表明S/O在低O/H时较大。光电离模型证实O（+）/O（2+）和S（+）/S（2+）观测值可以用来估算H Ⅱ区电离星的有效温度。这为研究外星系H Ⅱ区电离星提供了一个潜在的强有力的新工具。然而，对于合理的T（eff）值，模型不能再现具有大O（2+）分数的星云中的S（+）/S（2+）比。简单的化学演化模型计算比较观测与恒星核合成计算的期望。参考文献84篇。
A long-slit CCD survey of forbidden S III 9069, 9532 A radiation in 13 extragalactic H II regions is presented, and the data are used to study the variation of S/O as a function of O/H. The data are consistent with the idea that S/O remains constant as O/H varies. There is no evidence that S/O is larger at low O/H. Photoionization models confirm that observations of O(+)/O(2+) and S(+)/S(2+) can be used to estimate the effective temperature of the ionizing stars in an H II region. This provides a potentially powerful new tool for studying the ionizing stars of H II regions in external galaxies. However, the models fail to reproduce the S(+)/S(2+) ratio in nebulae with large O(2+) fractions for reasonable values of T(eff). Simple chemical evolution models are calculated to compare observations with expectations from stellar neucleosynthesis calculations. 84 refs.