Debris disk size distributions: steady state collisional evolution with Poynting-Robertson drag and other loss processes
Debris disk size distributions: steady state collisional evolution with Poynting-Robertson drag and other loss processes
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碎片盘尺寸分布：坡印廷-罗伯逊阻力和其他损失过程的稳态碰撞演化
DOI：
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Booth
中科院分区：
文献类型：
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作者：
M. Wyatt;C. Clarke;M. Booth
我们提出了一个新的计划，用于确定的大小分布的形状，及其演变，碰撞级联的星子进行破坏性的碰撞和损失过程，如坡印廷-罗伯逊阻力。该计划对待的稳态部分的级联相等的质量损失和增益在每个尺寸箱，最小的粒子预计达到稳定状态的碰撞时标，而较大的粒子保留其原始分布。对于碰撞主导的磁盘，稳态意味着对数尺寸箱中的质量损失率与尺寸无关。这个处方再现了预期的两相尺寸分布，波纹以上的吹出的大小，以上的重力主导的星子强度的过渡。该方案还再现了预期的磁盘质量和尘埃质量的演变，但在计算上比时间向前发展的分布快得多。对于低质量的盘，P-R阻力导致小尺寸的翻转到由再分布函数（碰撞中产生的碎片的质量分布）设定的尺寸分布。因此，有关再分布函数的信息可以通过测量经历P-R阻力损失的粒子的尺寸分布来恢复，例如通过在地球上吸积的粒子来跟踪。虽然在PR主导的制度下，横截面积随着年龄下降，但尘埃质量福尔斯下降，这强调了在考虑磁盘可探测性如何演变时，了解哪些颗粒尺寸有助于观察的重要性。其他损失过程很容易纳入，我们还讨论了广义幂律损失率，动态损耗，现实的辐射力和恒星风阻力。
We present a new scheme for determining the shape of the size distribution, and its evolution, for collisional cascades of planetesimals undergoing destructive collisions and loss processes like Poynting-Robertson drag. The scheme treats the steady state portion of the cascade by equating mass loss and gain in each size bin; the smallest particles are expected to reach steady state on their collision timescale, while larger particles retain their primordial distribution. For collision-dominated disks, steady state means that mass loss rates in logarithmic size bins are independent of size. This prescription reproduces the expected two phase size distribution, with ripples above the blow-out size, and above the transition to gravity-dominated planetesimal strength. The scheme also reproduces the expected evolution of disk mass, and of dust mass, but is computationally much faster than evolving distributions forward in time. For low-mass disks, P-R drag causes a turnover at small sizes to a size distribution that is set by the redistribution function (the mass distribution of fragments produced in collisions). Thus information about the redistribution function may be recovered by measuring the size distribution of particles undergoing loss by P-R drag, such as that traced by particles accreted onto Earth. Although cross-sectional area drops with age $${propto t^{-2}}$$ in the PR-dominated regime, dust mass falls $${propto t^{-2.8}}$$ , underlining the importance of understanding which particle sizes contribute to an observation when considering how disk detectability evolves. Other loss processes are readily incorporated; we also discuss generalised power law loss rates, dynamical depletion, realistic radiation forces and stellar wind drag.
DOI：
10.1088/0004-637x/691/2/l133
发表时间：
2009-02
期刊：
The Astrophysical Journal
影响因子：
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作者：
S. Stewart;Z. Leinhardt
通讯作者：
S. Stewart;Z. Leinhardt