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

白矮星(WD)是作为恒星演化终点产生的最常见的塌缩天体。它们的天体物理行为取决于它们的内部组成，它们既影响着这些物体从出生就冷却的速度，也影响着它们如何在以后的生命中通过吸收附近伴星的物质而被加热到高温时作为超新星爆炸。可以通过研究周期为100-1000秒的某些体积振荡的性质来探索深层的内部成分。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。WD内部最丰富的原子核，仅次于碳和氧，是一种倾向于向WD中心下沉的Ne同位素。要解释对这些天体的观测，需要对这个项目进行理论建模，以了解霓虹沉积和随后的成分梯度如何影响振荡和冷却时间。该项目的第二个方面源于最近在质量转移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。对于这种环境中的这种天体，需要另一套理论计算，以便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WD属性的测量，如质量和自转速度。

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.***