0 Assigned ID: 139 ----- Attempting Submission 1 (Wed Apr 03 17:16:34 GMT 2019) ----- HST Phase I Proposal 139 (Cycle27_Hyakutake_AR_APT.pdf.apt) successfully submitted. Receipt: # 139-1 ----- Attempting Submission 2 (Thu Apr 04 23:27:02 GMT 2019) ----- Disintegration may be the leading cause of the demise of cometary nuclei, yet is rarely observed and not well understood. We propose to use an amazing but largely unpublished HST archival dataset on comet C/Hyakutake to characterize the fragmentation of this body. The observations are especially valuable because of the fortuitously small geocentric distance (0.1 AU minimum), giving extreme resolution and sensitivity to small fragments and debris. We will measure the number, sizes, velocities, dust properties, production rates and ejected mass, and we will search post-perihelion images for evidence of further disintegration. A nucleus/coma convolution model will be used to extract the best estimates of the coma-free sub-nucleus dimensions. David Jewitt has an extensive record of research into the study of small solar system bodies, especially the Kuiper belt objects and the cometary nuclei. In the last decade he has written 19 refereed papers based on Hubble data. His role will be to lead the project to prompt publication. Jing Li is experienced with data reduction and numerical modeling techniques. She has reduced and measured all Hubble from a large SNAP investigation of distant Centaurs, with a paper in submission to AJ. Her role will be to organize, prepare, measure and co-model the data for fundamental parameters of the secondary components and dust sheet. Solar System 0 Regular false false false false false SUPPORTED