Cosmic-Ray Neon, Wolf-Rayet Stars, and the Superbubble Origin of Galactic Cosmic Rays
Cosmic-Ray Neon, Wolf-Rayet Stars, and the Superbubble Origin of Galactic Cosmic Rays
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DOI：
10.1086/496959
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发表时间：
2005-08
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通讯作者：
W. Binns;M. Wiedenbeck;M. Arnould;A. Cummings;J. George;S. Goriely;M. Israel;R. Leske;R. Mewaldt;G. Meynet;L. Scott;E. Stone;T. T. Rosenvinge-T.
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作者：
W. Binns;M. Wiedenbeck;M. Arnould;A. Cummings;J. George;S. Goriely;M. Israel;R. Leske;R. Mewaldt;G. Meynet;L. Scott;E. Stone;T. T. Rosenvinge-T.
我们利用先进成分探测器（ACE）上的宇宙射线同位素光谱仪（CRIS）的数据报告了银河宇宙射线（GCRs）中氖同位素的丰度。这些丰度已经在84≤E/M≤273 MeV核子-1的能量范围内的7个能量区间进行了测量。我们利用测量的21Ne、19F和17O丰度作为二次生成氖同位素的“示踪剂”，推导出了宇宙射线源处22Ne/20Ne的比值。利用该方法，我们得到的宇宙射线源22Ne/20Ne丰度比为0.387±0.007（统计）±0.022（系统）。这相当于在太阳风中22Ne/20Ne的比值增加了5.3±0.3倍。这个宇宙射线源22Ne/20Ne的比值也明显大于在异常宇宙射线、太阳高能粒子、大多数陨石物质样本和行星际尘埃粒子中发现的比值。我们将ACE CRIS的氖和难熔同位素比值数据以及其他实验数据与双组分Wolf-Rayet （W-R）模型的最新结果进行了比较。这些模型预测的GCR同位素比值与太阳系比值的三个最大偏差，12C/16O， 22Ne/20Ne和58Fe/56Fe，确实存在于GCR中。事实上，我们测量的所有同位素比率都与GCR源一致，该源由大约80%的太阳系成分和大约20%的W-R物质组成。由于W-R星是OB星的演化产物，而大多数OB星存在于OB星群中，形成超级气泡，因此这些数据与W-R模型的良好一致性表明，超级气泡可能是至少相当一部分gcr的来源。
We report the abundances of neon isotopes in the Galactic cosmic rays (GCRs) using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). These abundances have been measured for seven energy intervals over the energy range of 84 ≤ E/M ≤ 273 MeV nucleon-1. We have derived the 22Ne/20Ne ratio at the cosmic-ray source using the measured 21Ne, 19F, and 17O abundances as "tracers" of secondary production of the neon isotopes. Using this approach, the 22Ne/20Ne abundance ratio that we obtain for the cosmic-ray source is 0.387 ± 0.007(statistical) ± 0.022(systematic). This corresponds to an enhancement by a factor of 5.3 ± 0.3 over the 22Ne/20Ne ratio in the solar wind. This cosmic-ray source 22Ne/20Ne ratio is also significantly larger than that found in anomalous cosmic rays, solar energetic particles, most meteoritic samples of matter, and interplanetary dust particles. We compare our ACE CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (W-R) models. The three largest deviations of GCR isotope ratios from solar system ratios predicted by these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are indeed present in the GCRs. In fact, all of the isotope ratios that we have measured are consistent with a GCR source consisting of about 80% material with solar system composition and about 20% W-R material. Since W-R stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with W-R models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.