论文标题
破坏长期彗星
Destruction of Long-Period Comets
论文作者
论文摘要
我们确定了27个长期彗星的样本，非重力加速度和基于Lyman-Alpha的气体产量都可以使用。 27颗彗星中有7颗（即25％）由于碎裂或完全分解而无法生存。从经验上讲，后一种核的气体产量最小，是最大的非重力加速度，这都是小尺寸的指标。具体而言，瓦解核的中值半径仅为0.41 km，是存活的近日的1.60 km中位半径的四分之一。分解的彗星的围围侧距离（0.48 au）也比幸存者（0.99 au）较小。我们将超出扭矩的数量级时间尺度比较，以改变核的旋转tau，而每个彗星在强升华中花费的时间DT，发现被破坏的彗星是tau <dt的彗星。因此，由于旋转破裂而自然而然地解释了近阳性长期彗星的破坏。我们讨论了这一过程，以此作为Oort长期神秘的``褪色参数''的贡献。
We identify a sample of 27 long-period comets for which both non-gravitational accelerations and Lyman-alpha based gas production rates are available. Seven of the 27 comets (i.e. 25 percent) did not survive perihelion because of nucleus fragmentation or complete disintegration. Empirically, the latter nuclei have the smallest gas production rates and the largest non-gravitational accelerations, which are both indicators of small size. Specifically, the disintegrating nuclei have a median radius of only 0.41 km, one quarter of the 1.60 km median radius of those surviving perihelion. The disintegrating comets also have a smaller median perihelion distance (0.48 au) than do the survivors (0.99 au). We compare the order of magnitude timescale for outgassing torques to change the nucleus spin, tau, with the time spent by each comet in strong sublimation, Dt, finding that the disrupted comets are those with tau < Dt. The destruction of near-Sun long-period comets is thus naturally explained as a consequence of rotational break-up. We discuss this process as a contributor to Oort's long mysterious ``fading parameter''.
