arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1107.2657astro-ph.GA
收藏

磷的星系演化

The Galactic evolution of phosphorus

E. Caffau, P. Bonifacio, R. Faraggiana, M. Steffen

备注：
To be published on A&A
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

随着星系的演化，其化学成分发生变化，不同元素的丰度比是潜在演化过程的有力探针。磷是一种直到现在还很难理解其演化的元素，因为它在冷恒星中很难被探测到。在1050-1082 nm处的多重峰1的红外弱PI线是磷存在的最可靠的指示。在VLT的CRIRES的可用性允许访问这个波长范围的恒星光谱。我们试图测量银河系盘中的20个冷星的磷丰度。的光谱进行了分析与一维模型计算的局部热力学平衡（LTE）的气氛。假设LTE执行线形成计算。磷与铁的比例与硫的比例相似，在金属量较低的恒星中增加。它与硫的比率大致恒定，略大于太阳能，[P/S]=0.10+- 0.10。我们成功地朝着理解银河系中磷的化学演变迈出了重要的一步。然而，观测到的P/Fe丰度比的上升比Kobayashi及其合作者开发的银河系化学演化模型预测的要陡。磷的演化似乎与轻的奇Z元素钠和铝不同。[P/S]与金属丰度的恒定值意味着P的产生对中子过剩不敏感，因此除了中子捕获之外的过程也在进行。我们认为质子捕获30 Si和α捕获27美元铝是可能的调查。我们看不出有行星的恒星和没有探测到行星的恒星的结果之间有明显的区别。

英文摘要：

As a galaxy evolves, its chemical composition changes and the abundance ratios of different elements are powerful probes of the underlying evolutionary processes. Phosphorous is an element whose evolution has remained quite elusive until now, because it is difficult to detect in cool stars. The infrared weak P I lines of the multiplet 1, at 1050-1082 nm, are the most reliable indicators of the presence of phosphorus. The availability of CRIRES at VLT has permitted access to this wavelength range in stellar spectra.We attempt to measure the phosphorus abundance of twenty cool stars in the Galactic disk. The spectra are analysed with one-dimensional model-atmospheres computed in Local Thermodynamic Equilibrium (LTE). The line formation computations are performed assuming LTE. The ratio of phosphorus to iron behaves similarly to sulphur, increasing towards lower metallicity stars. Its ratio with respect to sulphur is roughly constant and slightly larger than solar, [P/S]=0.10+- 0.10. We succeed in taking an important step towards the understanding of the chemical evolution of phosphorus in the Galaxy. However, the observed rise in the P/Fe abundance ratio is steeper than predicted by Galactic chemical evolution model model developed by Kobayashi and collaborators. Phosphorus appears to evolve differently from the light odd-Z elements sodium and aluminium. The constant value of [P/S] with metallicity implies that P production is insensitive to the neutron excess, thus processes other than neutron captures operate. We suggest that proton captures on 30Si and alpha captures on $27Al are possibilities to investigate. We see no clear distinction between our results for stars with planets and stars without any detected planet.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑