Probing the Deep Interiors of Accreting White Dwarfs through Studies of their Non-Radial Oscillations

白矮星（WDs）是最常见的坍缩天体，是恒星演化的终点。它们的天体物理行为取决于它们的内部组成，这既影响了这些天体从诞生开始冷却的速度，也影响了它们在生命后期通过吸积附近伴星的物质而加热到高温时如何爆炸成超新星。通过研究某些周期为100-1000秒的体积振荡的性质，可以探测到深部的内部成分。这个项目是对这些非径向振荡的理论研究，它解决了一些前沿问题。除了碳和氧之外，黑洞内部最丰富的原子核是氖的同位素，它倾向于向黑洞中心下沉。解释这些天体的观测结果需要对该项目进行理论建模，以了解振荡和冷却时间如何受到氖沉降和随之产生的成分梯度的影响。该项目的第二个方面来自最近在传质双星系统中发现的脉动WD。这一发现开辟了天体物理学的一个新领域。为了将观测到的与这些恒星的自转周期相当的脉动周期转换为质量和自转速率等WD特性的测量值，在这种环境下，这类天体需要另一套理论计算

AST-0205956PI BildstenWhite dwarfs (WDs) are the most common collapsed objects produced as end points of stellar evolution. Their astrophysical behavior depends on their interior composition affecting both the rate at which these objects cool from birth and how they explode as supernovae if heated to high temperatures later in life by accreting material from a nearby companion star. Deep interior compositions may be probed by studying the properties of certain volumetric oscillations having periods of 100-1000 seconds. This project is a theoretical investigation of these non-radial oscillations and it addresses certain frontier questions. The most abundant atomic nucleus in the WD interior after carbon and oxygen is an isotope of neon that tends to sink towards the WD center. Interpreting observations of these objects requires the theoretical modeling of this project to understand how the oscillations and the cooling times are affected by the neon sedimentation and consequent composition gradient. A second aspect of this project follows from the recent discovery of a pulsating WD in a mass transferring binary system. This finding has opened up a new field in astrophysics. Another set of theoretical calculations are required for such objects in this environment in order to convert observed pulsation periods that are comparable to the rotation periods of these stars into measurements of WD properties such as mass and the rotation rate.***