论文标题
Charon上的陨石坑：来自跨性别物体之间碰撞级联的影响器
Craters on Charon: Impactors From a Collisional Cascade Among Trans-Neptunian Objects
论文作者
论文摘要
我们考虑碰撞级联反应的平衡大小分布是否与Charon New Horizons火山口的影响器的频率相匹配（Singer等人，2019年）。使用分析模型和一组数值模拟，我们证明了碰撞的级联产生波浪尺寸分布。波浪的形态取决于固体的结合能$ q_d^\ star $和碰撞速度$ v_c $。对于采用的最小固体尺寸，$ r_ {min} $ = 1微米，碰撞速度$ v_c $ = 1-3 km/sec，波浪对$ q_d^\ star $的重力组件不太敏感。如果$ q_d^\ star $的批量强度成分是$ q_s r^{e_s} $，用于radius $ r $的粒子，则具有小$ q_s $的大小分布比具有大$ q_s $的粒子更为波动。 $ e_s \约-0.4 $的系统比$ e_s \大约0 $的系统具有更强的波浪。与新的视野数据的详细比较表明，在弱冰（Leinhardt＆Stewart 2012）和正常冰（Schlichting等，2013年）之间具有庞大强度的固体中的碰撞级联反应，可产生与Charon撞击器尺寸分布相似的大小分布。如果原始星云的表面密度$σ$随着半轴轴$ a $而变化，则$σ\ 30〜 {\ rm g〜cm^{ - 2}}}（a / {\ rm 1〜au}） 10-30 Myr 25 au。尽管有必要对Kuiper带进行更完整的进化计算，但碰撞级联对于产生固体的尺寸分布是一个可行的模型，该模型在其整个历史上都影响了Charon。
We consider whether equilibrium size distributions from collisional cascades match the frequency of impactors derived from New Horizons crater counts on Charon (Singer et al 2019). Using an analytic model and a suite of numerical simulations, we demonstrate that collisional cascades generate wavy size distributions; the morphology of the waves depends on the binding energy of solids $Q_d^\star$ and the collision velocity $v_c$. For an adopted minimum size of solids, $r_{min}$ = 1 micron, and collision velocity $v_c$ = 1-3 km/sec, the waves are rather insensitive to the gravitational component of $Q_d^\star$. If the bulk strength component of $Q_d^\star$ is $Q_s r^{e_s}$ for particles with radius $r$, size distributions with small $Q_s$ are much wavier than those with large $Q_s$; systems with $e_s \approx -0.4$ have stronger waves than systems with $e_s \approx 0$. Detailed comparisons with the New Horizons data suggest that a collisional cascade among solids with a bulk strength intermediate between weak ice (Leinhardt & Stewart 2012) and normal ice (Schlichting et al 2013) produces size distributions fairly similar to the size distribution of impactors on Charon. If the surface density $Σ$ of the protosolar nebula varies with semimajor axis $a$ as $Σ\approx 30~{\rm g~cm^{-2}} (a / {\rm 1~au})^{-3/2}$, the time scale for a cascade to generate an approximate equilibrium is 100-300 Myr at 45 au and 10-30 Myr at 25 au. Although it is necessary to perform more complete evolutionary calculations of the Kuiper belt, collisional cascades are a viable model for producing the size distribution of solids that impacted Charon throughout its history.
