论文标题
在古典诺瓦中混合分数
Mixing fraction in classical novae
论文作者
论文摘要
语境。经典Novae由在积聚白矮人（WDS）表面发生的热核逃亡者提供动力。在观察结果中，已经检测到了Nova弹出物中重元素的富集，表明在Nova爆发之前，基础WDS的外层中的积聚物和物质之间存在混合过程。但是，古典Novae中的混合部分仍然不确定。 目标。本文的目的是调查Nova爆发期间的一些元素丰度比，这些比率可用于估计古典Novae中的WD混合部分。 方法。通过考虑与恒星天体物理学实验（MESA）实验的恒星演化代码模块的不同WD混合，我们进行了一系列NOVA爆发的模拟，其中最初的Co WD质量在$ 0.7-1.0 \，M_ \ odot $中。 结果。我们确定了四个元素丰度比（即$ \ rm（h+he）/\ sum cno $，$ \ rm（h+he）/ne $，$ \ rm \ rm \ sum cno/mg，$和$ \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm \ rm/si $最合适的混合仪。我们还估计了某些代表性的古典Novae中的WD混合部分。此外，我们发现，在Nova爆发过程中，更高的金属性（即更高的WD混合分数）优先伴随着更长的$ t _ {\ rm 2} $（从峰值发光度下降了两个幅度）。我们的结果可用于限制经典Novae中的混合过程。
Context. Classical novae are powered by thermonuclear runaways occurring on the surface of accreting white dwarfs (WDs). In the observations, the enrichments of heavy elements in nova ejecta have been detected, indicating a mixing process between the accreted matter and the matter from the outer layers of the underlying WDs prior to nova outbursts. However, the mixing fraction in classical novae is still uncertain. Aims. The purpose of this article is to investigate some elemental abundance ratios during nova outbursts that can be used to estimate the WD mixing fraction in classical novae. Methods. By considering different WD mixing fractions with the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA), we carried out a series of simulations of nova outbursts, in which the initial CO WD masses range from $0.7-1.0\,M_\odot$. Results. We identified four elemental abundance ratios (i.e. $\rm (H+He)/\sum CNO$, $\rm (H+He)/Ne$, $\rm \sum CNO/Mg,$ and $\rm \sum CNO/Si$) that satisfy the conditions for determining the WD mixing fraction, in which $\rm (H+He)/\sum CNO$ is the most suitable mixing meter. We also estimated the WD mixing fraction in some representative classical novae. Additionally, we found that a higher metallicity (i.e. higher WD mixing fraction) is preferentially accompanied by a longer $t_{\rm 2}$ (the time of decline by two magnitudes from peak luminosity) during nova outbursts. Our results can be used to constrain the mixing process in classical novae.
