论文标题
Yarkovsky效应年代的Clarissa家庭年龄
Clarissa Family Age from the Yarkovsky Effect Chronology
论文作者
论文摘要
Clarissa家族是一个由原始C型小行星组成的小型碰撞家族。它位于内部小行星带的动态稳定区域中。在这项工作中，我们通过对Yarkovsky效应引起的行星扰动以及家庭成员的热漂移来确定Clarissa家族的形成年龄。使用修改的Swift-RMVS4集成器进行仿真，以说明Yarkovsky和Yarkovsky-O'Keefe-Radzievskii-Paddack（YORP）效果。我们进行了多次模拟，从碎片的不同弹性速度场开始，最初逆行旋转的比例不同，还测试了不同的Yarkovsky/YORP模型。我们的目标是与观测到的Clarissa家族的轨道结构相匹配，Clarissa家族在适当的半轴轴上显着不对称。最佳拟合是最初的射血速度<〜20 m/s的直径D = 2 km片段，4：1 YORP偏爱旋转的偏爱，并假设80％的小家庭成员最初具有逆行旋转。对于假定的小行星密度为1.5 g/cm3的Clarissa家族的年龄为56 +/- 6 MYR。密度对较小或较小的价值的较小变化将导致年龄稍大或年龄较大的年龄估计。这是Yarkovsky效应年表成功应用于100岁以下的小行星家族的第一种情况。
The Clarissa family is a small collisional family composed of primitive C-type asteroids. It is located in a dynamically stable zone of the inner asteroid belt. In this work we determine the formation age of the Clarissa family by modeling planetary perturbations as well as thermal drift of family members due to the Yarkovsky effect. Simulations were carried out using the Swift-rmvs4 integrator modified to account for the Yarkovsky and Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effects. We ran multiple simulations starting with different ejection velocity fields of fragments, varying proportion of initially retrograde spins, and also tested different Yarkovsky/YORP models. Our goal was to match the observed orbital structure of the Clarissa family which is notably asymmetrical in the proper semimajor axis. The best fits were obtained with the initial ejection velocities < ~20 m/s of diameter D=2 km fragments, 4:1 preference for spin-up by YORP, and assuming that 80% of small family members initially had retrograde rotation. The age of the Clarissa family was found to be 56+/-6 Myr for the assumed asteroid density 1.5 g/cm3. Small variation of density to smaller or larger value would lead to slightly younger or older age estimates. This is the first case where the Yarkovsky effect chronology has been successfully applied to an asteroid family younger than 100 Myr.
