论文标题
放宽粘弹性不倒翁，并应用于1I/2017（`oumuamua）和4179 Toutatis
Relaxation of Viscoelastic Tumblers with Application to 1I/2017 (`Oumuamua) and 4179 Toutatis
论文作者
论文摘要
通过观察非主要轴（NPA）状态旋转的彗星和小行星的动机，我们研究了自由预孔的三轴椭圆形旋转器朝向其最低能量的旋转状态的松弛。 proseviess的放松是由自旋的自我磨碎和惯性力产生的内部耗散应力引起的。我们开发了一种一般理论，以确定旋转器中的粘弹性应力，在任何线性流变学下，对于长轴（LAM）和短轴（SAM）模式。通过连续力学的方法，我们计算了应力场和粘弹性材料应变耗散的功率，从而使我们能够确定进动抑制的时间尺度。为了说明如何使用该理论，我们将框架应用于麦克斯韦政权下的三轴1I/2017（`oumuamua）和4179 Toutatis。对于前者而言，采用非常冷单石的小行星典型的粘弹性参数使衰减的时间尺度更长的$ 10^{10} $，并且比依靠$ \，Q $ - Q $ -FACTOR方法的工程中的时间表更高，而后者则可以将shorter shorterscale as a Shorefientiations a SpecranciTiations a Profcientiations a Prokentionctiations axpections。我们进一步将三轴理论降低到植物的几何形状的身体，并得出一个相对简单的分析近似家族，确定麦克斯韦旋转器的NPA衰减时间，以及确定在弛豫过程中自我实现是否可以忽略的标准。与数值集成相比，我们的近似值显示出靠近非截止性物体的相对误差不超过$ 0.2 \％$，对于高能量散发旋转器而言，$ 0.002 \％$。
Motivated by the observation of comets and asteroids rotating in non-principal axis (NPA) states, we investigate the relaxation of a freely precessing triaxial ellipsoidal rotator towards its lowest-energy spin state. Relaxation of the precession arises from internal dissipative stresses generated by self-gravitation and inertial forces from spin. We develop a general theory to determine the viscoelastic stresses in the rotator, under any linear rheology, for both long-axis (LAM) and short-axis (SAM) modes. By the methods of continuum mechanics, we calculate the power dissipated by the stress field and the viscoelastic material strain which enables us to determine the timescale of the precession dampening. To illustrate how the theory is used, we apply our framework to a triaxial 1I/2017 (`Oumuamua) and 4179 Toutatis under the Maxwell regime. For the former, employing viscoelastic parameters typical of very cold monolithic asteroids renders a dampening timescale longer by a factor of $10^{10}$ and higher than the timescales found in the works relying on the $\,Q$-factor approach, whilst the latter yields a significantly shorter timescale as a consequence of including self-gravitation. We further reduce our triaxial theory to bodies of an oblate geometry and derive a family of relatively simple analytic approximations determining the NPA dampening times for Maxwell rotators, as well as a criterion determining whether self-gravitation is negligible in the relaxation process. Our approximations exhibit a relative error no larger than $0.2\%$, when compared to numerical integration, for close to non-dissipative bodies and $0.002\%$ for highly energy dissipating rotators.
