NOAO >   Observing Info >   Approved Programs >   2014B-0185

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Proposal Information for 2014B-0185


PI: Beatrice Mueller, Planetary Science Institute, mueller@psi.edu
Address: 1700 E. Ft. Lowell, #106, Tucson, Arizona 85719, United States

CoI: Nalin Samarasinha, Planetary Science Institute

Title: Determination of an accurate rotation period for comet 19P/Borrelly: Tying Changes in Rotation to Activity

Abstract: In a recent paper, Samarasinha & Mueller (2013) introduced a parameter, X, to describe the changes in the rotational period of a comet in terms of the rotational period itself, the effective nuclear radius, and the orbital characteristics. They showed that X should be a constant if the bulk densities and shapes of the nuclei are nearly identical and the activity patterns are similar for all comets. For four nuclei (2P/Encke, 9P/Tempel 1, 10P/Tempel 2, and 103P/Hartley 2) for which rotational changes are well documented, despite the nearly factor 30 variation observed among the effective active fractions of these comets, X is constant to within a factor two (see Table 1). If that is the case for all comets, one can use this to predict rotational changes of comets. We will determine an accurate rotation period for comet 19P/Borrelly and the change in its rotation period over time. The proposed observations for comet 19P/Borrelly, together with approved observations in April and May, 2014 for comets 46P/Wirtanen and P/2004 R1 (McNaught) will be used to confirm the near-constancy of the parameter X and will nearly double the data base of comets with known rotational changes.


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