Jana Pittichova - Research Interests
*** Current Research ***
Long term ground-based observing support for Deep Impact and Startdust
space missions. Phomoteric measurements and data calibration.
Accurate determination of the rotation period of comet 9P/Tempel 1,
which appears to have change as a consequence of 2005 asymmetric
out-gassing torques. This is critical for enabling the science associate
with the Startdust-NExT mission. Extensive and severe observing seach and image
enhance and combining techniques to recover the lost comet Boethin, the
original target for the Epoxy space mission.
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 ***
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