论文标题
一个基于证据的假设，有助于减少观察到的$^7 $之间的差异
An evidence-based assumption that helps to reduce the discrepancy between the observed and predicted $^7$Be abundances in novae
论文作者
论文摘要
最近对谐振宽度的等效宽度为ii doublet和Ca II K线的最新光谱测量及其在扩展Nova exta的比例表明，$^7 $的高丰度与典型的质量分数$ x__ \ mathrm {obsrm {obs}（obs}（obs}（^7 \ mathrm {be} be}）这是一个比理论上预测的$ x_ \ mathrm {theor}（^7 \ mathrm {be}）\ sim 10^{ - 5} $的数量级。我们使用$^7 $ be生产方程的分析解决方案来证明$ x_ \ mathrm {theor}（^7 \ mathrm {be}）$与$^4 $ he质量分数$ y $成比例，然后在Nova增值信封中进行确认，然后我们根据$ 1. $ 1的$ 1.15 \ \ f \ y NOVA，MOD co f \ f \ f \ y NOVA \ \ \ \ f.分析解决方案。我们的增强$^4 $ HE的假设有助于减少，尽管没有完全消除，但$ x_ \ mathrm {obs}（^7 \ mathrm {be}）$和$ x_ \ mathrm {theor}（theor}（^7 \ Mathrm {be}）$之间的差异。它得到了紫外线，光学和红外光谱数据的支持，这些数据揭示了Nova弹出中$ y $的异常高值。我们还表明，$^3 $ HE在Nova的信封中显着增加并不会导致$ x_ \ Mathrm {theor}（^7 \ Mathrm {be}）$更高的值，因为此假设会影响Nova的演变，从而降低了它们的峰值和增值量的$ boses $ sand $ nove $ nove $ nova and $ nove $ nova and $ nove $ nova and $ nove $ nova and $ nove $ nova and $ nove $ nove $ nove and a in a Rede in a Rede in Rede in a Redal in Rede in Reda而言。
Recent spectroscopic measurements of the equivalent widths of the resonant Be II doublet and Ca II K lines and their ratios in expanding nova ejecta indicate surprisingly high abundances of $^7$Be with a typical mass fraction $X_\mathrm{obs}(^7\mathrm{Be}) = 10^{-4}$. This is an order of magnitude larger than theoretically predicted values of $X_\mathrm{theor}(^7\mathrm{Be})\sim 10^{-5}$ for novae. We use an analytical solution of the $^7$Be production equations to demonstrate that $X_\mathrm{theor}(^7\mathrm{Be})$ is proportional to the $^4$He mass fraction $Y$ in the nova accreted envelope and then we perform computations of 1D hydrostatic evolution of the $1.15\,M_\odot$ CO nova model that confirm our conclusion based on the analytical solution. Our assumption of enhanced $^4$He abundances helps to reduce, although not completely eliminate, the discrepancy between $X_\mathrm{obs}(^7\mathrm{Be})$ and $X_\mathrm{theor}(^7\mathrm{Be})$. It is supported by UV, optical and IR spectroscopy data that reveal unusually high values of $Y$ in nova ejecta. We also show that a significantly increased abundance of $^3$He in nova accreted envelopes does not lead to higher values of $X_\mathrm{theor}(^7\mathrm{Be})$ because this assumption affects the evolution of nova models resulting in a decrease of both their peak temperatures and accreted masses and, as a consequence, in a reduced production of $^7$Be.
