Planetary nebulae abundances and stellar evolution
Planetary nebulae abundances and stellar evolution
复制标题
行星状星云丰度和恒星演化
DOI：
--
复制
发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Bernard
中科院分区：
文献类型：
--
作者：
S. Pottasch;J. Bernard
摘要给出了ISO测量的行星状星云丰度。结果表明，这些星云显示丰度梯度（与银河系中心距离），其中氖，氩，硫和氧（四个例外）的情况下，是相同的HII区和早期类型的星星丰度梯度。根据这些梯度预测的这些元素在太阳到中心的距离上的丰度正是太阳的丰度。硫是例外，这是讨论的原因。更高的太阳氖丰度得到证实，这是讨论的结果日震。证据是氧破坏通过ON循环发生在四个行星状星云的祖先双叶结构。这些恒星的质量很大，可能超过5个太阳质量。这是从这些星云中发现的高He/H和N/H值推断出来的。讨论了氮、氦和碳的形成。显示氧破坏的高质量祖细胞被证明可能也破坏了碳。这可能是热底部燃烧的结果。
A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted from these gradients at the distance of the Sun from the center are exactly the solar abundance. Sulfur is the exception to this; the reason for this is discussed. The higher solar neon abundance is confirmed; this is discussed in terms of the results of helioseismology. Evidence is presented for oxygen destruction via ON cycling having occurred in the progenitors of four planetary nebulae with bilobal structure. These progenitor stars had a high mass, probably greater than 5 solar masses. This is deduced from the high values of He/H and N/H found in these nebulae. Formation of nitrogen, helium and carbon are discussed. The high mass progenitors which showed oxygen destruction are shown to have probably destroyed carbon as well. This is probably the result of hot bottom burning.