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arXiv 1107.4894astro-ph.HE
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巨星核合成与INTEGRAL

Massive-Star Nucleosynthesis and INTEGRAL

Roland Diehl

摘要:

用SPI在INTEGRAL上测量了来自恒星核合成的产物:来自长寿命的26 Al和60 Fe同位素的放射性衰变以及来自44 Ti衰变(衰变时间89 y)的特征伽马射线线。对这两种同位素的探测为通过这些测量的不同观点窥视恒星内部奠定了基础。伽马射线通量可以转换成这些放射性同位素的数量,但是对于大质量恒星模型来说,由此产生的限制涉及额外的步骤。早期的结果已经证明了这种放射性数据固有的基本约束,即26 Al的检测是对双恒星产额的校准,60 Fe可以进行同位素产额比测试,消除建模和观察偏差方面,44 Ti搜索表明其生产不会均匀地发生在核心坍塌事件中。26 Al和60 Fe的观测和分析的现状已经达到了天体物理学研究的门槛:最近已经研究了大质量恒星群的特定区域及其放射性伽马射线,例如Sco-Cen和Orion。至于44 Ti,光谱信息约束这些内部超新星喷出物的Cas A事件的喷射速度。大质量恒星的这些参数可以与天文学、核物理实验和理论以及理论天体物理学的其他领域联系起来。因此,模型改进出现在地平线上,例如在欧洲科学基金会的EuroGenesis计划框架中实施。

英文摘要:

Products from massive-star nucleosynthesis have been measured with SPI on INTEGRAL: Characteristic gamma-ray lines from radioactive decays of long-lived 26Al and 60Fe isotopes, and from 44Ti decay (decay time 89y). Detections of both these isotopes has laid the foundation to peek into massive-star interiors, through different views at those measurements. The gamma-ray flux can be converted into amounts of these radioactive isotopes, but the constraints which derive from this for massive star models involve additional steps. -- Earlier results had demonstrated the basic constraints inherent to such radioactivity data, i.e. detection of 26Al is a calibration for massive-star yields, 60Fe enables an isotopic-yield ratio test eliminating modeling and observing bias aspects, and 44Ti searches showed that its production does not occur homogeneously over core-collapse events. The current status of 26Al and 60Fe observations and their analysis is reaching a threshold for astrophysical insights: Specific regions of massive star groups and their radioactivity gamma-rays have recently been investigated, such as Sco-Cen and Orion. As for 44Ti, spectroscopical information constrains ejection velocities of these inner supernova ejecta for the Cas A event. These parameters for massive stars can be related to other fields of astronomy, of nuclear physics experiments and theory, and of theoretical astrophysics. Thus, model improvements appear on the horizon, as e.g. implemented in the EuroGenesis program framework of the European Science Foundation.

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