来自银河系中大质量恒星的放射性铝-26 。

Radioactive 26Al from massive stars in the Galaxy.

作者信息

Diehl Roland, Halloin Hubert, Kretschmer Karsten, Lichti Giselher G, Schönfelder Volker, Strong Andrew W, von Kienlin Andreas, Wang Wei, Jean Pierre, Knödlseder Jürgen, Roques Jean-Pierre, Weidenspointner Georg, Schanne Stephane, Hartmann Dieter H, Winkler Christoph, Wunderer Cornelia

机构信息

Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching, Germany.

出版信息

Nature. 2006 Jan 5;439(7072):45-7. doi: 10.1038/nature04364.

DOI:10.1038/nature04364

PMID:16397491

Abstract

Gamma-rays from radioactive 26Al (half-life approximately 7.2 x 10(5) years) provide a 'snapshot' view of continuing nucleosynthesis in the Galaxy. The Galaxy is relatively transparent to such gamma-rays, and emission has been found concentrated along its plane. This led to the conclusion that massive stars throughout the Galaxy dominate the production of 26Al. On the other hand, meteoritic data show evidence for locally produced 26Al, perhaps from spallation reactions in the protosolar disk. Furthermore, prominent gamma-ray emission from the Cygnus region suggests that a substantial fraction of Galactic 26Al could originate in localized star-forming regions. Here we report high spectral resolution measurements of 26Al emission at 1808.65 keV, which demonstrate that the 26Al source regions corotate with the Galaxy, supporting its Galaxy-wide origin. We determine a present-day equilibrium mass of 2.8 (+/- 0.8) solar masses of 26Al. We use this to determine that the frequency of core collapse (that is, type Ib/c and type II) supernovae is 1.9 (+/- 1.1) events per century.

摘要

来自放射性26铝（半衰期约为7.2×10⁵年）的伽马射线提供了银河系中持续进行的核合成的“快照”视图。银河系对这类伽马射线相对透明，并且已发现其发射集中在银河系平面上。这导致得出结论，银河系中质量巨大的恒星主导了26铝的产生。另一方面，陨石数据显示了本地产生26铝的证据，可能来自原太阳盘中的散裂反应。此外，天鹅座区域显著的伽马射线发射表明，银河系中相当一部分26铝可能起源于局部恒星形成区域。在此，我们报告了在1808.65千电子伏特处对26铝发射的高光谱分辨率测量结果，这些结果表明26铝源区域与银河系共转，支持其在整个银河系的起源。我们确定了目前26铝的平衡质量为2.8（±0.8）个太阳质量。我们据此确定核心坍缩（即Ib/c型和II型）超新星的频率为每世纪1.9（±1.1）次事件。