Constraining models of activity on comet 67P/Churyumov-Gerasimenko with Rosetta trajectory, rotation, and water production measurements.Nongravitational Effects of Cometary Activity.Peak Effective Active Fraction over the surface of 67P for a model fit to geological unit types. Finally, we also compare the trajectory information, in the form of Earth-to-comet range, with the new analysis of Rosetta radio-tracking data performed in. This provides an additional constraint on the spatial distribution of activity. In addition to the changes in rotation period examined in, we also compute changes in the rotation axis, using a method based on in order to compare with the observations. The objective here is to constrain the shape of the activity curve on these various surfaces that a more detailed thermal model (see, for example ) must produce in order to fit the data. This will have important implications for understanding how activity works on the different types of surface observed on cometary nuclei, including ‘rough’, ‘smooth’, ‘dusty’ and ‘rocky’ surface morphologies. Here we are able to achieve a good fit to the Rosetta data by parameterizing EAF in terms of the different geological unit types on 67P (Fig. We investigate different spatial patterns in EAF, and attempt to correlate them to physical features on the cometary surface. We test a number of different activity distributions over the surface of the comet by varying the Effective Active Fraction (EAF), relative to pure water ice, of facets on a shape model. Here we will present ongoing work, testing various activity distributions in an effort to fit Rosetta outgassing, trajectory, and rotation data using the activity model of. For comet 67P/Churyumov-Gerasimenko, detailed measurements have been made by the Rosetta spacecraft and various attempts have been made to model the activity (see, e.g. Outgassing produces a reaction force on nuclei that can alter their trajectory and spin, allowing constraints to be placed on comet models by measuring the observed orbit and rotation changes. 21, 1992).Understanding cometary activity is key to exploring their materials and surface physics, with implications for comet formation and subsequent evolution. Please see additional reproduction and reuse information at. Preferred credit line is: Courtesy, the Sonoma County Library. USERS ARE SOLELY RESPONSIBLE for determining the existence of such rights and for obtaining any permissions and/or paying associated fees necessary for the proposed use. Any other kind of use, including, but not limited to commercial or scholarly publication in any medium or format, public exhibition, or use online or in a web site, may be subject to additional restrictions including but not limited to the copyrights held by parties other than the Library. However, these images are intended for Personal or Research use only. Neither the Sonoma County Library nor the Sonoma County Bar Association make any assertions as to ownership of any original copyrights to digitized images and can claim only physical ownership of the image(s) described in this records. "Nick" DeMeo, Career of Distinction Award recipient Creator Schroll, Kenneth E., 1918-2009Ĭollection Sonoma County Bar Association Collection, 1881-2014 (SPC.00003)
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