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arXiv 0912.2142astro-ph.SRastro-ph.GA
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渐近巨分支模型的恒星产额更新

Updated stellar yields from Asymptotic Giant Branch models

Amanda I. Karakas

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Accepted for publication in MNRAS; 15 pages
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摘要：

更新了低到中等质量热脉冲渐近巨星分支（AGB）星的恒星产额网格。这些模型涵盖了金属量Z = 0.02、0.008、0.004和0.0001的范围，质量在1 Msun到6 Msun之间。新的中等质量Z = 0.0001 AGB模型，以及更精细的质量网格比以前的研究中使用的。产率计算使用更新的反应速率网络，其中包括最新的NeNa和MgAl质子捕获率，与主要结果之间的约6至30倍的钠产生的中间质量模型与热底部燃烧。在低质量的AGB模型，我们调查的影响，包括一些部分混合质子到壳层间区域的最深程度的每三个疏浚情节的轻元素的生产。质子被丰富的12 C捕获，形成13 C口袋。13 C口袋增加了19 F、23 Na、富中子的Mg和Si同位素、60 Fe和31 P的产率。根据金属丰度的不同，31 P的增加约为4至20倍。将13 C口袋添加到He-中间壳层中所引起的任何结构变化均被忽略。然而，所考虑的模型是低质量的，任何这样的反馈可能是小的。需要进一步的研究来测试部分混合模型的产量的准确性。对于每一个质量和金属丰度，产额都以表格的形式呈现，适合用于银河系化学演化研究或与行星状星云的组成进行比较。

英文摘要：

An updated grid of stellar yields for low to intermediate-mass thermally-pulsing Asymptotic Giant Branch (AGB) stars are presented. The models cover a range in metallicity Z = 0.02, 0.008, 0.004, and 0.0001, and masses between 1Msun to 6Msun. New intermediate-mass Z = 0.0001 AGB models are also presented, along with a finer mass grid than used in previous studies. The yields are computed using an updated reaction rate network that includes the latest NeNa and MgAl proton capture rates, with the main result that between ~6 to 30 times less Na is produced by intermediate-mass models with hot bottom burning. In low-mass AGB models we investigate the effect on the production of light elements of including some partial mixing of protons into the intershell region during the deepest extent of each third dredge-up episode. The protons are captured by the abundant 12C to form a 13C pocket. The 13C pocket increases the yields of 19F, 23Na, the neutron-rich Mg and Si isotopes, 60Fe, and 31P. The increase in 31P is by factors of ~4 to 20, depending on the metallicity. Any structural changes caused by the addition of the 13C pocket into the He-intershell are ignored. However, the models considered are of low mass and any such feedback is likely to be small. Further study is required to test the accuracy of the yields from the partial-mixing models. For each mass and metallicity, the yields are presented in a tabular form suitable for use in galactic chemical evolution studies or for comparison to the composition of planetary nebulae.

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