Measured thermal properties of a Main Belt Comets (MBCs) and to use these to develop models of the thermal evolution, the current volatile components, and the mechanism of the cometary activity. Using Finson-Probstein dust modeling techniques to determine when the cometary activity began near perihelion, constrain the dust size distribution. This information is use to estimate gas outflow velocities, which in turn provides constrains on the thermal models in colaboration with Dr. Dina Prialnik.
Investigate how surface properties of icy bodies in the Solar System change as the bodies age. Compare the colors and albedos of the inner Solar System short-period comets (JFCs) with those of dynamically related bodies of the outer Solar System, Centaurs and trans-Neptunian objects (TNOs). Focusing on objects that have most recently transitioned from the Centaur population to the JFC population, in collaboration with Dr. Fernandez.
Study dust characteristics, search for possible organic (PAH-like) signature and address a fundamental question - the origins of crystalline silicates in the solar nebula. Provide ground-base observations of selected sublimating comets as a comprehensive survey of faint Jupiter-family comets (JFCs) dust properties, which will permit an in-depth, systematic comparison of JFCs and Oort Cloud comet physical characteristics, in collaboration with Dr. Woodward.
Searching for an activity of distance comets and determination of the heliocentric distance for a turn on/off the nuclues activity. Observations of comets at large heliocentric distances will support the experimental simulation of ice grain ejection from cometary nuclei proposed by Dr. Akiva Bar-Nun.
Optical and spectroscopy observations of comets 42P/Neujmin3 and 53P/VanBiesbroeck, which have very well determined orbits, and their orbital histories are very interesting. Their current orbits are very dissimilar; however, numerical integrations have shown that in the middle of January, 1850 both comets approached within 0.1 AU of Jupiter, and prior to January of 1850, their orbits were nearly identical. Our goal is to compare the ratios of common gas species that can be expected from these comets. This will be the first time when we can find out the similar origin base on physical study and not only from dynamical models.
The analysis and calibration of photometric CCD imaging data of comets which are possible targets for the planning Space Mission - mostly Deep Impact.
Long-term observations of the dust coma activity of bright comets, looking of the pre- and post-perihelion changes.
Searching for Sungrazing Coments and lost comets.
*** Comet Morphological Study ***
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The primary objectives of the proposed investigation are to understand,
to the extent possible, the physical properties of a cometary nucleus and its
particulate ejecta, and to characterize the proposes and evolution of dust
emission from the nucleus. The prime object of study is comet Hale-Bopp,
for which large numbers of optical and infrared CCD images were obtained.
Additional objects may be added, depending on appropriate data becoming
available in the course of this investigation.
It is contemplated that the approach to achieve these objectives will proceed along three lines of analysis: morphology, optical photometry, and thermal-emission photometry of the dust coma on available images.
The purpose of morphological studies is too establish the pattern of dust emission from the nucleus, which is determined by the surface distribution of discrete sources of dust on the rotating nucleus and their temporal evolution. Completion of morphological analysis is a prerequisite for photometry both in the optical wavelengths and in the thermal infrared.
Morphological analysis has two major steps. The first step is a computer processing of the images to enhance the visibility of the critical morphological features in the dust coma (such as jets, spirals, fans, streamers, etc.).
The second step of the morphological analysis is the modelling of the observed dust features in terms of the dust-source distribution on the rotating nucleus and its temporal evolution. The main part of this modelling is a Monte Carlo simulation code that generates synthetic images of the dust coma for any chosen time. Dust particles are ejected from discrete emission sources on the sunlit side of the nucleus with initial velocities that depend on particle mass and size and on heliocentric distance; the grains are then subjected to solar radiation pressure, which also depends on particle mass and size and on heliocentric distance. The emission sources are characterized by their locations on the nuclear surface and by their dust production rates. The nucleus is assumed to rotate along a spin axis and to have a particular spin rate.
When upgraded, the code will offer simultaneous synthetic images of the dust coma in the optical and thermal-infrared regions of the spectrum. It will constrain greatly the range of acceptable models for the comet and will lead to a more realistic, synergistic interpretation of the entire data set and to a considerable insight into the issues of dust emission from comets. As a by-product, it will -- as it does now -- provide information on the rotation state of the comet's nucleus.
Combination of optical and infrared data will be possible to receive information on the gas production rates and derive additional fundamental quantities on the comet, with potential implications for compositional and evolutionary investigations of comets in general.
Collaboration and participation with Dr. Meech's on her new three years NASA grant with an international collaboration with Dr. Dina Prialnik on a project of Sophisticated 1-D spherically symmetric thermal models combine Monte Carlo code and Finson-Probstein dust models.
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Last modified: Februar 27, 2008