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2007 Annual Science Report

NASA Goddard Space Flight Center Reporting  |  JUL 2006 – JUN 2007

Accomplishments of Graduate Student William Anderson

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Mr. William Anderson is a graduate student at the Catholic University of America, pursuing his Ph. D. under the mentorship of GCA co-I Michael DiSanti. His thesis topic is a comparative study of the chemistry of oxidized carbon among comets belong to two principal dynamical reservoirs: Long-period comets, coming from the Oort cloud, and short-period comets that are in dynamical resonance with the Sun and Jupiter (the so-called “Jupiter Family” comets, JFCs). The JFCs are thought to come primarily from the scattered Kuiper disk population of comets.

Anderson is currently finalizing his work on comet T7 LINEAR, and is planning to defend his thesis in late 2007 or early 2008. His absolute production rates for CO, H2CO, and CH3OH demonstrate that methanol and formaldehyde are unusually abundant relative to CO (Anderson et al. 2006). A paper is in preparation that will report the oxidized carbon chemistry from data obtained on two observing runs of several days each that are separated by several weeks. These data quantify abundance changes for CO, H2CO, and CH3OH relative to H2O, and thus test the internal heterogeneity of the comet nucleus.

Anderson also assisted in acquiring and analyzing simultaneous measurements of CO and H2O in comet 73P/Schwassmann-Wachmann 3, taken in May 2006 with CSHELL at the NASA Infrared Telescope Facility (Mauna Kea) (DiSanti et al. 2007). The mixing ratio of CO relative to water was only 0.5% ± 0.13%, in line with the severely depleted organic composition of this comet. Anderson also participated in observations of the long-period (Oort cloud) comet C/2006 M4 (SWAN) in November 2006 (DiSanti et al. 2007).

Conference Abstracts:

Anderson, W. M., M. A. DiSanti, M. J. Mumma, N. Dello Russo, B. P. Bonev, K. Magee-Sauer, and E. L. Gibb 2006, “Infrared Observations of Oxidized Carbon in Comet C/2002 T7 (LINEAR)”, BAAS 38(3), p.545, October 2006, Pasadena, CA. (Oral presentation at the 38th annual meeting of the Division for Planetary Sciences of the American Astronomical Society)

DiSanti, M. A., M. J. Mumma, B. P. Bonev, G. L.Villanueva, and W. M. Anderson 2007, “The Interesting Volatile Organic Composition of Comet C/2006 M4 (SWAN)”, Poster presentation at BioAstronomy 2007, June 2007 (San Juan, PR).