Deep Imaging of Dimorphos’s Dust Tail
National Aeronautics and Space Administration
Hubble Space Telescope General Observer Program-Cycle 30
Science PI: Jian-Yang Li (Sun Yat-sen University)
Non PSI Personnel: Yin Zhang (Co-Investigator, University of Maryland), Andrew Cheng (Co-Investigator, JHU APL), Steven Chesley (Co-Investigator, JPL), Eugene Fahnestock (Co-Investigator, Cal Tech), Tony Farnham (Co-Investigator, University of Maryland), Masatoshi Hirabayashi (Co-Investigator, Auburn University), Mathew Knight (Co-Investigator, U.S. Naval Academy), Ludmilla Kolokova (Co-Investigator, University of Maryland), Fernando Moreno (Co-Investigator, Instituto de Astrofisica de Andalucia), Andrew Rivkin (Co-Investigator, JHU APL), Gonzalo Tancredi (Co-Investigator, Universidad de La Republica Facultad de Ciencias), Cristina Thomas (Co-Investigator, N. Arizona University), Harold Weaver (Co-Investigator, JHU APL)
External Partners
- University of Maryland
- Sun Yat-sen University
- JHU APL
- JPL
- Cal Tech
- Auburn University
- U.S. Naval Academy
- Instituto de Astrofisica de Andalucia
- Universidad de La Republica Facultad de Ciencias
- N. Arizona University
Project Description
We will use 10 orbits to perform deep imaging of the dust tail of asteroid Dimorphos created by the DART impact with WFC3/UVIS in early July before the target moves into the solar avoidance zone. The observations will result in about 40 images through a single filter, F350LP. This set of data will be combined with the images collected from program HST-17292 to 1) Characterize the tail evolution and the large dust particles; 2) Determine the mechanisms for delayed particle release from the binary asteroid weeks after the impact; 3) Study the evolution of the tail in the context provided by the data from all previous observations of the tail; and 4) Support the comparative study of Dimorphos’s tail with those of the natural active asteroids triggered by episodic dust release.
We will then stack all image from each orbit, and stack all images from all orbits, clean up for cosmic rays and detector artifacts, measure aperture photometry, tail morphology (orientations and brightness distribution), and search for unusual morphological units in the tail. From these measurements in the stacked images, we will model the tail morphology with a dust dynamic model to understand the dynamics in the binary system that caused the delayed dust release as hinted by the previous observations. With these measurements, we will model the dynamical process of the ejecta particles using numerical simulations. The numerical code will be set up with the initial conditions of the ejecta dust constrained from observations, including the particle size and size distribution. We will explore a range of various ejecta initial speed and speed distribution using the constraints from impact process to match the observed temporal evolution of the tail. Numerical simulation of the dynamical process will both help characterize the large ejecta population and improve our understanding about the dynamic process of ejecta dust in the binary asteroid system, which is unique for our observations. We will also compare the tail evolution with the previously observed tails of active asteroids to provide context and gain insight about the understanding of nature active asteroids. The constraints to the large ejecta particles will help the DART mission to refine the total ejecta mass and velocity-mass distribution measurements, contributing to the estimate of momentum transfer coefficient. Finally, we will also search for large ejecta blocks in all long-exposure stacks and, if identified, measure their size and size distribution, and positions in the sky.