Mommert, M. and Harris, A. W. and Trilling, D. E. and Mueller, M. and Hora, J. L. and Delbo, M. and Bottke, W. F. and Emery, J. P. and Fazio, G. and Hagen, A. R. and Morbidelli, A. and Smith, H. A. and Thomas, C. A. (2012) ExploreNEOs: A Search for Near-Earth Objects of Cometary Origin. 44th annual meeting of the Division for Planetary Sciences of the American Astronomical Society, 14.-19. Okt. 2012, Reno, NV.
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The short dynamical lifetime of near-Earth objects (NEOs) compared to the age of the Solar System implies the existence of sources of replenishment in order to maintain the observed population of NEOs. Main belt asteroids and Jupiter family comets (JFCs), which can end up in typical NEO orbits via planetary perturbations and non-gravitational forces, are the most important sources of replenishment of NEOs. JFCs that become NEOs suffer accelerated loss of their near-surface volatiles, evolving into inactive "dormant" or "extinct" comets that are observationally indistinguishable from low albedo asteroids. Dynamically, however, they retain "comet-like" orbital characteristics. Knowledge of the fraction of extinct comets in the NEO population is important for assessing the amount of cometary material that has been transported to Earth. Furthermore, identifying inactive comet candidates facilitates detailed investigations of the final phase of comet evolution. We present an independent analysis of the fraction of former cometary objects in the NEO population. Due to the large number of NEOs we use a statistical approach to identify dormant or extinct comets based on dynamical and physical properties. We utilize (1) the Tisserand parameter with respect to Jupiter, (2) the minimum orbit intersection distance with respect to Jupiter and (3) albedo measurements. Our albedos are determined from thermal-IR observations made by the Warm Spitzer Space Telescope Exploration Science project "ExploreNEOs", using thermal modeling. The main goal of this work is to estimate the fraction of dormant or extinct comets in the NEO population. We will further provide a list of former comet candidate objects and assess their accessibility with spacecraft via the delta-V parameter. We enhance our investigation by adding data from the literature to our sample and compare our results to earlier published works based on independent analyses. MM acknowledges support by the DFG SPP 1385.
|Document Type:||Conference or Workshop Item (Speech)|
|Title:||ExploreNEOs: A Search for Near-Earth Objects of Cometary Origin|
|Keywords:||NEOs, Spitzer, dead comets|
|Event Title:||44th annual meeting of the Division for Planetary Sciences of the American Astronomical Society|
|Event Location:||Reno, NV|
|Event Type:||international Conference|
|Event Dates:||14.-19. Okt. 2012|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Space|
|HGF - Program Themes:||Space Science and Exploration|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R EW - Erforschung des Weltraums|
|DLR - Research theme (Project):||R - Vorhaben Exploration des Sonnensystems|
|Institutes and Institutions:||Institute of Planetary Research > Asteroids and Comets|
|Deposited By:||Michael Mommert|
|Deposited On:||09 Nov 2012 10:24|
|Last Modified:||09 Nov 2012 10:24|
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