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Topic Name: Detailed Spectroscopic Investigation of Comet - Asteroid Transition Objects, Extinct Comets, and Their Possible Source Regions
Category: Photonics
Research persons: Paul Abell
Location: Washington DC, United States
Details
This investigation's objective is to obtain spectroscopic observations of
potential comet-asteroid transition objects and extinct comet candidates using
ground-based telescopes to attain the following goals:
1) Identify potential cometary candidates within the NEO population and
estimate the contribution from different cometary source regions.
2) Constrain the physical and spectral characteristics of cometary candidates
to better assess their relationships to meteorites, interplanetary dust
particles, and asteroids.
3) Examine possible relationships of the objects determined to be comets with
known source regions (e.g., Jupiter-family comets [Kuiper belt] and Halley-type
comets [Oort Cloud]).
This study will obtain spectra of objects selected on the basis of their
comet-like orbits, which are defined as having a Tisserand invariant under 3,
and only includes objects that are members of the NEO population, or which are
otherwise unusual (e.g., Damocloids). A list of 51 targets have been selected
with ~1/3 of these being NEOs and includes those objects with low (< 10 deg) and
high (> 10 deg) inclinations, which are indicative of Jupiter-family comets and
Halley-type comets, respectively. Some targets with comet-like albedos and low
heliocentric distances will produce thermal emission in their infrared spectra.
Analyses of these spectra from such targets will help determine their albedos
(or constrain their albedos if no thermal emission is detected) and further aid
in the characterization of these objects as potential extinct/dormant comets.
Results from objects already observed suggest that there are differences in
the spectral signatures between objects that have originated from the Kuiper
belt and Oort Cloud. The planned observations should be sufficient to sample the
materials present among comet-asteroid transition objects, and constrain the
relative contributions of specific cometary source regions to these populations.
This investigation will lead to better understandings of the final stages of
cometary evolution, and contribute to the overall physical characterization of
cometary nuclei.
About the Researcher :
Paul Abell
Planetary Astronomy Program (NASA)
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