论文标题
磁场对白色矮人周围碎屑盘动力学的影响
The Effect of a Magnetic Field on the Dynamics of Debris Discs Around White Dwarfs
论文作者
论文摘要
寿命的观察估计值和从污染白矮人周围的碎屑盘的增生率通常与屏蔽的Poynting-Robertson模型的预测不一致。此外，许多凉爽的污染白矮人没有显示出任何随附的光盘的观察证据。这可以部分解释，如果碎片盘的寿命较短，积聚率要比仅Poynting-Robertson Drag所预测的要高。我们考虑了磁场对潮汐破坏的磁磁碎片的作用及其对碎屑盘形成，进化和增生速率的后续影响。我们估计，磁场强度大于$ \ sim $ 10kg可能会使圆形化和圆盘寿命所需的时间减少几个数量级，并将相关的吸积率增加到相似的因素，相对于Poynting-Robertson的阻力。我们建议一些受污染的白色矮人可能在典型可检测的极限以下设有磁场，并且这些磁场可能是污染的白矮星中缺少碎屑盘的污染的一部分。我们还建议，Dimamnetic阻力可能解释了被污染的白色矮人的较高积聚率估计值，这些估计无法完全通过Poynting-Robertson阻力来预测，并发现对磁场强度，轨道上心距离的依赖性，以及粒子对预测的盘寿命和积聚率和积聚率。
Observational estimates of the lifetimes and inferred accretion rates from debris discs around polluted white dwarfs are often inconsistent with the predictions of models of shielded Poynting-Robertson drag on the dust particles in the discs. Moreover, many cool polluted white dwarfs do not show any observational evidence of accompanying discs. This may be explained, in part, if the debris discs had shorter lifetimes and higher accretion rates than predicted by Poynting-Robertson drag alone. We consider the role of a magnetic field on tidally disrupted diamagnetic debris and its subsequent effect on the formation, evolution, and accretion rate of a debris disc. We estimate that magnetic field strengths greater than $\sim$10kG may decrease the time needed for circularisation and the disc lifetimes by several orders of magnitude and increase the associated accretion rates by a similar factor, relative to Poynting-Robertson drag. We suggest some polluted white dwarfs may host magnetic fields below the typical detectable limit and that these fields may account for a proportion of polluted white dwarfs with missing debris discs. We also suggest that diamagnetic drag may account for the higher accretion rate estimates among polluted white dwarfs that cannot be predicted solely by Poynting-Robertson drag and find a dependence on magnetic field strength, orbital pericentre distance, and particle size on predicated disc lifetimes and accretion rates.
