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Project Progress

Molecules in Interstellar Cloud Cores:
Understanding the nature of the natal interstellar cloud is crucial to understanding the chemistry of the solar nebula, and hence the chemistry of the Sun and planets. Since that cloud no longer exists, it is necessary to study the cores of existing dense interstellar clouds where stars are forming. Moreover, since the physical conditions vary among and within such clouds, it is important to investigate the chemical and physical processes in a variety of such environments.

Irvine and colleagues in Korea have been studying molecular clouds in the vicinity of the center of our Milky Way Galaxy, where various energetic processes can influence the chemical composition of molecular clouds. They observed millimeter-wave transitions of the molecules CO, HCO+, HNCO, and SiO toward the Sgr A region using the SEST telescope at LaSilla, Chile. The comparison of the observed transitions shows that the several prominent gas condensations in this region have very distinctive chemical properties with respect to each other, which may result from differing physical conditions in the various locations (Minh et al., 2005). In particular, it seems likely that the chemistry is influenced by shocks produced by the source
Sg A East.

The effect of shocks may be especially pronounced in the case of sulfur-containing molecular species such as H₂S. We have mapped the distribution of emission from H₂S in the Galactic Center region, and conclude that its abundance is enhanced by shocks that may originate in regions of massive star formation such as Sgr B2 (Minh et al, 2004).

Graduate student Jonathan Franklin studied the distribution of H₂O in regions of massive star formation, using data from the Submillimeter Wave Astronomy Satellite (SWAS). The results were compared to the distribution of other molecular species as obtained with the University of Massachusetts’ 14-m diameter radio telescope at the Five College Radio Astronomy Observatory. A paper is being prepared for publication.

The chemistry of comets:
Irvine completed work on a review chapter for the book, Comets II, on the subject of the processes undergone by organic matter that is cycled through interstellar cloud environments, into a forming solar system, and then into primitive bodies such as comets (Irvine and Lunine, 2004).

Irvine is part of a team that has a pending proposal for Target of Opportunity observations of molecular emission lines from bright comets at millimeter/sub-millimeter wavelengths, using the JCMT on Mauna Kea (Matthews et al., 2004). Unfortunately, no useful data were obtained during the period of this report, but the proposal remains active.

Reviews and Conferences Related to Astrobiology:

As part of his participation in a Working Group on “Prebiotic Chemistry: from the Interstellar Medium to the Solar System”, sponsored by the International Space Science Institute in Berne, Switzerland, Irvine acted as a co-editor on a review of the current state of Astrobiology. This volume will serve as advice and background information for the European Space Agency and European universities on Exo/Astrobiology research programs and mission-related experiments (Ehrenfreund, Irvine et al., 2004a). As part of this effort, Irvine co-wrote a chapter on the future of astrobiology (Ehrenfreund, Irvine, et al., 2004b).

Irvine was invited to present a review of organic chemistry in the interstellar medium and in comets for the Fourteenth International Congress on the Origin of Life, the triennial meeting of the International Society for the Study of the Origin of Life (ISSOL), to be held in Beijing in June, 2005. In addition, he will be a co-author on a review on future perspectives in astrobiology in the concluding session of the conference.

Irvine attended the annual meeting of the Division for Planetary Sciences of the American Astronomical Society in Louisville, KY, in November 2004, and presented a poster on applications of the Large Millimeter Telescope (see below) to astrobiology.

Irvine attended the Team Meeting of the Goddard Center for Astrobiology in January 2005 and described work related to this grant.

Facilities:

The Large Millimeter Telescope (LMT) is a joint project of the University of Massachusetts Amherst and the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) in Tonantzintla, Puebla, Mexico. The LMT will be the largest single-dish telescope in the world operating at short millimeter wavelengths when it is completed in 2007-08. It will be a powerful instrument for various fields within astrobiology, including the study of the chemistry and physics of comets, other primitive bodies in the solar system, planetary and satellite atmospheres, and the interstellar medium. Irvine continued as Chair of the Management Working Group and as a member of the Science Working Group for the Large Millimeter Telescope Observatory (LMTO), the US-Mexican organization that will operate the LMT.

Irvine spent the fall academic semester of 2004 on sabbatical leave at INAOE, developing scientific collaboration between INAOE and the University of Massachusetts and promoting the study of astrobiology in Mexico. He and Mexican colleagues are writing a short book about the LMT project (Irvine, Carrasco, and Aretxaga, 2005).

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Outreach:

The University of Massachusetts has initiated an interdisciplinary course for honors students entitled “Cosmos to Humanity: From the Big Bang to the Space Age”. The theme of the course is astrobiology/evolution, beginning with the evolution of the universe and continuing with the formation and evolution of the solar system, the origin and evolution of life, life in extreme environments, the evolution of complex life, the origin and evolution of humans, and the search for life elsewhere in the universe. Irvine has developed 6 lectures, associated reading material, and web-based units (http://bcrc.bio.umass.edu/courses/fall2005/biol/biol270h/)
for the course on the topics of cosmology, nucleosynthesis, organic matter in galaxies, the origin of the solar system, environments in the solar system for life, and extrasolar planets and the search for life in the universe. Martha Hanner, Adjunct Professor of Astronomy at the University of Massachusetts, received some support from this grant to participate in developing lectures and discussions on comets for this new course.