“SPINNING OUT OF CONTROL! How Sublimative Torques Alter And Destroy Cometary Bodies”<\/p>\n
Summary Additionally, I can explain both comet reactivation and the highly collimated outbursts seen at comets as direct results of avalanches triggered by rotation state changes.<\/p>\n
\n<\/strong>To quote David Levy: \u201ccomets are like cats: they have tails, and they do precisely what they want.\u201d\u00a0 They have strange bilobate nuclei, undergo outbursts (rapid, unpredictable brightening events), and form long\u00a0 striated dust features in their tails that somehow align with the Sun rather than the nucleus. Additionally, their dynamics appear to require\u00a0 some mysterious mechanism for reactivating their sublimative activity.\u00a0 In this talk, I describe how all of these features are a result of the\u00a0 way that volatile sublimation, the defining cometary process, affects irregularly shaped bodies. Asymmetric sublimative mass loss generates torques that change the rotation state of comet nuclei in a manner analogous to the YORP Effect. Such rotational spin-up can induce internal stresses that fission the nucleus, forming both cometary striae and the strange bilobate shape of 67P\/Churyumov-Gerasimenko.<\/p>\n