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

通过研究白矮星的非径向振荡来探索吸积白矮星的深层内部

• 批准号: 0205956
• 负责人: Lars Bildsten
• 金额: $ 30.94万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0205956&HistoricalAwards=false
• 关键词: Probing; Deep; Interiors; Accreting; White

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.***

AST-0205956 PI Bildsten白矮星（WD）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，这既影响了这些物体从出生时冷却的速度，也影响了它们在生命后期通过吸积附近伴星星星的物质而被加热到高温时如何爆炸成超新星。可以通过研究周期为100-1000秒的某些体积振荡的性质来探测深部内部的成分。该项目是对这些非径向振荡的理论研究，并解决了某些前沿问题。在WD内部，除了碳和氧之外，最丰富的原子核是倾向于向WD中心下沉的氖同位素。解释这些物体的观测需要该项目的理论建模，以了解振荡和冷却时间如何受到氖沉积和随之而来的成分梯度的影响。 这个项目的第二个方面是从最近发现的一个脉动WD在传质二元系统。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类物体，需要进行另一套理论计算，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对WD特性（如质量和自转速率）的测量。