New 34CI proton-threshold states and the thermonuclear 33S(p,γ)34Cl rate in ONe novae
New 34CI proton-threshold states and the thermonuclear 33S(p,γ)34Cl rate in ONe novae
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ONe 新星中新的 34CI 质子阈值状态和热核 33S(p,γ)34Cl 速率
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发表时间：
2009
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通讯作者：
D. Schafstadler
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作者：
A. Parikh;T. Faestermann;R. Kruecken;T. Behrens;V. Bildstein;S. Bishop;K. Eppinger;C. Herlitzius;C. Hinke;M. Schlarb;D. Seiler;Maier;R. Hertenberger;H. Wirth;Ludwig;D. Schafstadler
对原始陨石中的前太阳颗粒的分析表明，同位素比率在很大程度上是各种天体物理环境中普遍存在的条件的特征。一个可能的指标，一个晶粒的一个新星的起源是一个大的33 S丰度：核合成计算预测多达150倍的太阳33 S丰度的新星爆炸喷出物在大质量的一个白色矮星。然而，由于在新星峰温度（T峰~ 0.1-0.4 GK）下33 S（p，γ）34 Cl反应速率的几个数量级的不确定性，该过量生产因子可能至少以0.01-3的因子变化。这些不确定性的出现是由于缺乏核物理信息的状态在~600 keV的33 S + p阈值在34 Cl（Sp（34 Cl）= 5143 keV）。为了更好地限制这一速率，我们首次测量了~（34）S（~ 3 He，t）~（34）Cl反应在E_x（~ 34）Cl = 4.9-6 MeV区域的能量。我们确认了以前的状态，并发现15个新的国家在这个能源领域。新的33 S（p，γ）34 Cl共振在E-R = 281（2），301（2）和342（2）keV处可能在相关的新星温度下支配这一速率。我们的结果可能会影响新星喷出物中硫同位素比率的预测（例如，32 S/ 33 S），可以作为谷物新星亲缘关系的诊断工具。
Analysis of presolar grains in primitive meteorites has shown isotopic ratios largely characteristic of the conditions thought to prevail in various astrophysical environments. A possible indicator for a grain of ONe nova origin is a large 33 S abundance: nucleosynthesis calculations predict as much as 150 times the solar abundance of 33 S in the ejecta of nova explosions on massive ONe white dwarfs. This overproduction factor may, however, vary by factors of at least 0.01-3 because of uncertainties of several orders of magnitude in the 33 S(p,γ) 34 Cl reaction rate at nova peak temperatures (T peak ~ 0.1-0.4 GK). These uncertainties arise due to the lack of nuclear physics information for states within ~600 keV of the 33 S + p threshold in 34 Cl (S p ( 34 Cl) = 5143 keV). To better constrain this rate we have measured, for the first time, the 34 S( 3 He,t) 34 Cl reaction over the region E x ( 34 CI) = 4.9-6 MeV. We confirm previous states and find 15 new states in this energy region. New 33 S(p,γ) 34 Cl resonances at E R = 281(2), 301(2), and 342(2) keV may dominate this rate at relevant nova temperatures. Our results could affect predictions of sulphur isotopic ratios in nova ejecta (e.g., 32 S/ 33 S) that may be used as diagnostic tools for the nova paternity of grains.