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Project Progress

Pedelty, in collaboration with Mundy, planned and implemented Very Large Array (VLA) observations of the hot molecular cores (HMC) in the young stellar object IRAS 16293-2422. These 7 mm observations targeted the prebiotic molecules formic acid, methyl formate, and ethyl cyanide in sources A and B within this object. We generated ~2” spatial resolution images and spectra that detected formic acid and methyl formate in source B of this deeply embedded system. A protoplanetary disk in source B was recently revealed in a ~0.1” resolution VLA image obtained by Rodriguez et al. (2005, ApJ, 621, L133). We obtain a formic acid column density of ~3-7 × 10¹⁵ cm^-2 for temperatures of 60 — 110K. We combined our methyl formate observations with others recently obtained with the Submillimeter Array (Kuan et al. 2004, ApJ, 616, L27) and the Plateau de Bure Interferometer (Bottinelli et al. 2004, ApJ, 617, L69) to produce a rotation diagram for source B that is well fit by a temperature of 110K and a column density of 10¹⁷ cm^-2, as long as we exclude the transition at E_u = 454K that was marked as suspect by Kuan et al. These results were presented in a poster at the NAI General Meeting in Boulder, and a journal paper is in preparation.

Pedelty, Mundy, and Charnley wrote a successful VLA proposal in June 2005 for similar VLA
7 mm observations of the low mass star formation region NGC 1333 IRAS 4A. Two observing sessions should be scheduled by the end of 2005. NGC 1333 IRAS 4A and IRAS 16293-2422 are the only two lowmass star forming regions with published spectra showing HNC emission lines, and comparison of high resolution interferometric observations of IRAS 16293 and IRAS 4A should help us better understand their prebiotic chemistry.

Pedelty led the planning and execution in November 2004 of successful VLA observations of the Orion Molecular Cloud (OMC1), Trapezium, and BN region. These X-band (3.5cm) observations are in collaboration with Bally (co-I with NAI-U. Colorado) et al., with the goal of determining proper motions in this important stellar nursery.

Global Biomarkers in support of the Terrestrial Planet Finder Missions

Pedelty attended the Astronomy Focus Group meeting on Global Biomarkers for Extrasolar Planets in December 2004, co-chaired by Seager (NAI-Carnegie) and Meadows (NAI-Virtual Planetary Laboratory). The workshop’s goal was to determine global-scale biomarkers from past and present Earth, and their detectability in disk-averaged planetary spectra such as those to be obtained from the Terrestrial Planet Finder missions. Pedelty presented a brief summary of Earth Observing System data. Follow-on discussions led to a large collaborative proposal to the NASA Interdisciplinary Exploration Science program in June 2005. Meadows is PI and Pedelty is the GSFC institutional PI, and the proposal team includes VPL members and Earth scientists at GSFC.

ITWG Support

Pedelty continued to serve as GCA representative to the NAI IT Working Group (ITWG). He was responsible for maintaining the local installation of the PolyCom ViewStation and the WebEx PC to support virtual collaboration. He handled the technical aspects of the GCA’s participation in most Executive Council meetings and NAI seminars. Pedelty worked with NAI Central to host workshops and seminars such as the Methane on Mars workshop, Mumma\'s Director’s seminar, and FAR seminars by Bonev and the GCA summer students. In this role Pedelty attended several IT-related sessions at the NAI General Meeting and participated in regular ITWG video/teleconferences. He also provided IT support to the GCA comet group led by Mumma, assisting in the specification, purchase, and assembly/configuration of a new Apple G5 Xserve and RAID disk array.