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Project Reports

• 1. From Molecular Clouds to Habitable Planetary Systems

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1

• Module 1: The Building Blocks of Life

  Molecular material that may lead to life on planet surfaces has its origin in interstellar space. Using a combination of laboratory spectroscopic measurements and radio astronomical observations, this module has been tracing the life cycle of carbon and phosphorus containing compounds from their formation in outflows around old stars to their arrival on planet surfaces via exogenous delivery. We have been investigating what carbon and phosphorus compounds are found in matter lost from stars, and how the chemical composition changes as this material flows into the interstellar medium and forms dense clouds
  in space. We are following what happens to these compounds as these clouds evolve into solar systems, and how comets, meteorites, and dust particles may have brought interstellar pre-biotic material to Earth and other planets.

  ROADMAP OBJECTIVES: 3.1 3.2 4.2 7.1

• Abiotic Nitrogen Cycling

  This work considers how the chemistry in the atmosphere of Mars (and other “Earth-like” planets) may have affected life, including how prebiotic nitrogen species may have been formed for the origin of life, and how these atmospheres may have been changed. When too much nitrogen is removed from the atmosphere, this can result in a planet with too little atmospheric pressure to support liquid water and life on the surface.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 3.1

• Biomimetic Cluster Synthesis: Bridging the Structure and Reactivity of Biotic and Abiotic Iron-Sulfur Motifs

  Synthetic approaches are being utilized to bridge the gap between Fe-S minerals and highly evolved biological Fe-S metalloenzymes. These studies are focusing on organic template (protein) mediated cluster assembly (biomineralization), probing properties of synthetic clusters, both as homogeneous and heterogeneous catalysts, investigating the impact of size scale on the properties of synthetic Fe-S clusters, and computational modeling of the structure and catalytic properties of synthetic Fe-S nanoparticles in the 5-50 nm range.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2

• Computational Chemical Modeling the Link Between Structure and Reactivity of Iron-Sulfur Motifs

  The Fe-S mineral catalysis, Fe-S enzyme catalysis, and a biomimetic thrust areas of ABRC have their own unique ways to probe the relationships between structure and reactivity at the active sites of iron-sulfur enzymes and the structure and reactivity of iron-sulfur minerals. We have developed a cohesive link among these thrust areas through bridging the enzymatic/mineral catalysis and molecular structure/chemical reactivity by computational chemistry.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2

• Module 2: Formation of Habitable Planetary Systems

  Our goal is to understand the physical processes that lead to planet formation, with a focus on aspects that determine the suitability of those planets to harbor life. Our main tool to accomplish this goal is observational astronomy. We utilize a variety of ground- and space-based telescopes across the electro-magnetic spectrum to make observations of circumstellar disks around sun-like as a function of the age of each system in order to constrain theories of planet formation and evolution. A central aspect of this work is to understand chemical processes that occur in disks and how such processes determine the structure and composition of the planets formed from them.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1

• Advancing Techniques for in Situ Analysis of Complex Organics

  Our research in laser mass spectrometry is part of the overall program of the Goddard Center for Astrobiology to investigate the origin and evolution of organics in planetary systems. Laser mass spectrometry is a technique that is used to determine the chemical composition of sample materials such as rocks, dust, ice, meteorites in the lab. It also may be miniaturized so it could fit on a robotic spacecraft to an asteroid, a comet, or even Mars. On such a mission it could be used to discover any organic compounds preserved there, which in turn would give us insight into how Earth got its starting inventory of organic compounds that were necessary for life. The technique uses a high-intensity laser to “zap” atoms and molecules directly off the surface of the sample. The mass spectrometer instantly captures these particles and provides data that allow us to determine their molecular weights, and therefore their chemical composition. We are developing this technique to understand the mass spectra that would be obtained from a meteorite or an unknown rock sample encountered on a remote planetary mission.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.2 7.1

• 2. Extraterrestrial Materials: Origin and Evolution of Organic Matter and Water in the Solar System

  ROADMAP OBJECTIVES: 1.1 2.1 3.1

• Climate, Habitability, and the Atmosphere on Early Mars

  Atmospheric chemistry has profound implications for the climate and habitability of Mars throughout its history. The presence and stability of greenhouse gases and aerosols, for example, may regulate climate or force climate change. Chemical reactions in the atmosphere initiated by light (“photochemistry”) may also produce gases or aerosols that serve as a shield against ultraviolet light (as stratospheric ozone does on earth) and possibly warm or cool the surface, which, in turn, has implications for the presence and stability of water on Mars. Thus, understanding the chemical composition and physical properties of possible Martian atmospheres over time is vital to the understanding of the opportunities and challenges for early life on Mars, as well as the importance of habitat features that provide radiation protection. In this project, we are investigating in laboratory experiments how quickly photochemistry can destroy and produce various greenhouse gases and aerosols and whether or not the aerosols may serve to warm or cool the surface. We are also investigating whether or not these photochemical reactions can produce carbon-rich aerosols that might be depleted in the stable isotope carbon-13 relative to carbon-12, and thus might be mistaken for an isotopic signature produced by biological processes after the aerosols settle out of the atmosphere and become incorporated into the martian rock record or meteorites that have made it to earth.

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 6.1 7.1 7.2

• Molecular Beam Studies of Nitrogen Reactions on Iron-Sulfur Surfaces

  It is generally accepted that surface-mediated reactions occur on defect sites. The role of defects in the formation of ammonia is being evaluated using molecular beam-surface scattering experiments in which a deuterium atom plasma source is used to hydrogenate a pyrite surface with D atoms. The hydrogenated surface is subsequently bombarded with a molecular beam of energetic N2 molecules and the conversion of N2 to products such as ammonia is probed through mass spectrometry.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2

• 3. Prebiotic Chemical and Isotopic Evolution on Earth

  ROADMAP OBJECTIVES: 3.1 4.1 4.2 7.1

• A Self-Perpetuating Catalyst for the Production of Organics in Protostellar Nebulae

  When hydrogen, nitrogen and CO are exposed to amorphous iron
  silicate surfaces at temperatures between 500 – 900K, a carbonaceous
  coating forms via Fischer-Tropsch type reactions. Under normal
  circumstances such a catalytic coating would impede or stop further
  reaction. However, we find that this coating is a better catalyst than
  the amorphous iron silicates that initiate these reactions. The
  formation of a self-perpetuating catalytic coating on grain surfaces
  could explain the rich deposits of macromolecular carbon found in
  primitive meteorites and would imply that protostellar nebulae should be
  rich in organic material. Many more experiments are needed to
  understand this system and its application to protostellar systems.

  ROADMAP OBJECTIVES: 1.1 3.1

• Biological Potential of Mars

  We are exploring the geochemical environment of the martian surface and near-surface regions, in order to understand constraints on habitability by microorganisms. In particular, we are examining the chemical reactions that take (or took) place in the geological environment, and calculating the amounts of energy that are released that could by used by microbes to support metabolism. As chemical energy is the likely source of energy to support martian organisms, its tabulation provides a strong constraint on the amount of life that could have or can be supported there. We can compare the results to similar calculations in terrestrial environments, in order to compare martian and terrestrial habitability.

  ROADMAP OBJECTIVES: 2.1 3.1

• 4. Prebiotic Molecular Selection and Organization

  ROADMAP OBJECTIVES: 3.1 3.2 3.4 4.1 7.1

• Formation of Nitrogenated Aromatics in the Interstellar Medium

  We are investigating the chemical energetics and plausibility of reaction pathways leading to the formation of nitrogenated aromatics suggestive of purine and pyrimidine bases of RNA and DNA molecules using quantum chemistry.

  ROADMAP OBJECTIVES: 3.1

• Origin of Life and Catalysis – Philosophical Considerations

  Our goal is to provide a solid philosophical foundation for the ABRC research program. To achieve this goal, we have several sub-goals like helping the students to develop their position as a group regarding a viable account for the metabolism-first theory, examining some methodological assumptions of the current astrobiological community, and finally propagating the information learned in our group to a larger community by offering courses on the origin of life.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 4.2

• 5. Life in Extreme Environments

  ROADMAP OBJECTIVES: 3.1 5.1 5.3 6.2 7.1

• Probing the Structure and Nitrogen Reduction Activity of Iron-Sulfur Minerals

  Fe-S compounds are common in both biological and geological systems. The adaptation of Fe-S clusters from the abiotic world to the biological world may have been an early event in the development of life on Earth and possibly a common feature of life elsewhere in the universe. The Iron-sulfur mineral thrust of the ABRC is focused on examining the structure and reactivity of FeS minerals using nitrogen fixation as a model reaction.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2

• 6. Molecular and Isotopic Biosignatures

  ROADMAP OBJECTIVES: 2.1 3.1 4.1 4.2 5.3 6.1 7.1 7.2

• Structure, Function, and Biosynthesis of the Complex Iron-Sulfur Clusters at the Active Sites of Nitrogenases and Hydrogenases

  Iron-sulfur clusters are thought to be among the most ancient cofactors in living systems. The Fe-S enzyme thrust is focused on examining the structure, mechanism, and biosynthesis of the complex Fe-S enzymes nitrogenase and hydrogenase.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2

• Functional Genomics of Thioredoxins in Halobacterium Sp. NRC-1

  This project addresses the functions of an ancient protein family in Archaea that occupy extreme environments. Some of these proteins may play roles similar to those of comparable proteins in other living organisms, and thus may tell us about functions that evolved in the last universal common ancestor of life. Others may have evolved as the Archaea began to occupy specialized and often extreme environments. This project also addresses the emergence of proto-metabolic networks that supplied the precursors for the RNA World.

  ROADMAP OBJECTIVES: 3.1 3.2 5.1 5.3

• 7. Astrobiotechnology

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.2 5.3 6.2 7.1

• Isotopic Signatures of Methane and Higher Hydrocarbon Gases From Precambrian Shield Sites: A Model for Abiogenic Polymerization of Hydrocarbons

  Methane and higher hydrocarbon gases in ancient rocks on Earth originate from both biogenic and abiogenic processes. The measured carbon isotopic compositions of these natural gases are consistent with formation of polymerization of increasing long hydrocarbon chains starting with methane. Integration of carbon isotopic compositions with concentration data is needed to delineate the origin of hydrocarbon gases.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 4.1 4.2 6.1 7.1 7.2

• Planet Formation and Dynamical Modeling

  In this task, we use computer models of the formation of terrestrial planets and the chemistry in the protoplanetary disk to better understand how carbon, the backbone of life processes, becomes incorporated into
  forming planets. Our planet formation models are also being used to understand planet formation around low-mass stars and binary stars, and how tidal interactions between planet and star can cause a planet’s orbit to evolve
  over time, potentionally taking it into, or out of, the habitable zone.

  ROADMAP OBJECTIVES: 1.1 3.1 4.3

• Prebiotic Organics From Space

  This project has three components, all aimed to better our understanding of the connection between chemistry in space and the origin of life on Earth and possibly other worlds. Our approach is to trace the formation and evolution of compounds in space, with particular emphasis on identifying those that are interesting from a prebiotic perspective, and understand their possible roles in the origin of life on habitable worlds. We do this by first measuring the spectra and chemistry of materials under simulated space conditions in the laboratory. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes. We also carry out experiments on simulated extraterrestrial materials to analyze extraterrestrial samples returned by NASA missions or that fall to Earth in as meteorites.

  ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.4 4.3 7.1 7.2

• Current Status and Future Bioastronomy With the Large Millimeter Telescope

  Irvine and colleagues at the University of Massachusetts have been using a unique new broadband radio receiver to measure the spectra of external galaxies in the 3mm wavelength region. The so-called Redshift Search Receiver has an instantaneous bandwidth of 36 GHz, providing the opportunity to simultaneously observe most of the 3mm spectrum of a galaxy, and hence to measure the molecular emissions in this band. It is ultimately intended for use on the Large Millimeter Telescope; however, until the LMT is completed, the receiver is being tested at the Five College Radio Astronomy Observatory’s 14-meter telescope, operated by the University of Massachusetts. Early results indicate that there are striking differences in the apparent chemical composition of molecular clouds in different galaxies. Theoretical work suggests that the relevant effects include differences in both ultraviolet and X-ray environments, and in the importance of shocks.

  ROADMAP OBJECTIVES: 3.1

• Training for Oxygen: Peroxy in Rocks, Early Life and the Evolution of the Atmosphere

  We try to find answers to a range of deep questions about the early Earth and about the origin and early evolution of life. How did the surface of planet Earth become slowly but inextricably oxidized during the first 2 billion years? We present evidence that it was not through the early introduction of oxygenic photosynthesis but through a purely abiotic process, driven by the tectonic forces of the early Earth and the weathering cycle. Only much later in Earth’s history, about 2.4 billion years ago, did photosynthesis kick in, boosting the oxygen level in the atmosphere to the levels that we enjoy now. If this is so, other Earth-like planets around other stars can be expected to undergo the same evolution from an early reduced state to an oxidized state.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 4.1 7.2

• Philosophical Problems in Astrobiology; Issues on the Origin of Life,

  My project is exploring philosophical issues in astrobiology. My central focus this year was on the origin of life: what is the proper level of analysis for a successful theory of the origin of life? Among other things, I compared and contrasted contemporary scientific theories of the origin of life in light of what philosophers of science have learned about the structure and justification of scientific theories.

  ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 4.1 4.2

• Planet Formation and Dynamical Modeling

  ROADMAP OBJECTIVES: 1.1 3.1 6.2

• Organic and Inorganic Acids From Ion-Irradiated Ices

  Scientists at the Cosmic Ice Laboratory with the Goddard Center for Astrobiology study the formation and stability of molecules under conditions found in outer space. During the past year, amino acids found in meteorites were investigated, including some acids not found in terrestrial biology. Carbonic acid, a very unstable molecule on Earth, also was studied since it will be stable under Martian conditions and environments in the outer solar system. These projects are part of the Comic Ice lab’s continuing contributions to understanding the chemistry of biologically-related molecules and chemical reactions in extraterrestrial environments.

  ROADMAP OBJECTIVES: 2.2 3.1 7.1

• Stability of Methane Hydrates in the Presence of High Salinity Brines on Mars

  Laboratory experiments were used to monitor the influence of increasing salinity on the stability of ices composed of water, methane, and carbon dioxide. New data show that these types of hydrates decease in stability as salinity increases, suggesting that lateral or vertical migration of brines in the subsurface of Mars could cause release of methane and carbon dioxide to surface sediments and the atmosphere. These experimental results are important for interpreting reports of methane in the Martian atmosphere.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 7.1 7.2

• Origin and Evolution of Organics

  The central goal of the Blake group effort in the NASA GSFC Astrobiology node (Origin and Evolution of Organics in Planetary Systems (Mike Mumma, P.I.) is to determine whether complex organics such as those seen in meteorites are detectable in the circumstellar accretion disks that encircle young stars and in the comae of comets. Our program has both observational and laboratory components. We use state-of-the-art telescopes from microwave to optical frequencies, and we have developed novel high frequency and temporal resolution instruments that seek to utilize the unique properties of the terahertz (THz) modes of complex organics. Future observations of such modes with the Herschel and SOFIA observatories promise to revolution our understanding of prebiotic chemistry in both our own and other solar systems.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1

• Origin and Evolution of Organics in Planetary Systems

  Professor Fegley’s group at Washington University in St Louis modeled chemistry of outgassed volatiles during accretion of the Earth. Accretion of the Earth, and especially the Moon-forming impact, heats the Earth to temperatures high enough to melt and vaporize its silicate crust and mantle. The Earth has a silicate atmosphere during this phase of its history. As the Earth cools down, the silicate atmosphere collapses and a steam atmosphere forms. This atmosphere is not pure steam, but contains H₂O, H₂, CO, CO₂, CH₄ in varying proportions depending on temperature and pressure. Further cooling leads to a collapse of the steam atmosphere and a gaseous atmosphere forms. This is an early reducing atmosphere with CH₄, H₂, NH₃, and water vapor.

  ROADMAP OBJECTIVES: 1.1 3.1 3.2

• The Diversity of the Original Prebiotic Soup: Re-Analyzing the Original Miller-Urey Spark Discharge Experiments

  Recently obtained samples from some of the original Stanley Miller spark discharge experiments have been reanalyzed using High Pressure Liquid Chromatography-Flame Detection and Liquid Chromatography-Flame Detection/Time of Flight-Mass Spectrometry in order to identify lesser constituents that would have been undetectable by analytical techniques 50 years ago. Results show the presence of several isoforms of aminobutyric acid, as well as several serine species, isomers of threonine, isovaline, valine, phenylalanine, ornithine, adipic acid, ethanolamine and other methylated and hydroxylated amino acids. Diversity and yield increased in experiments utilizing an aspirating device to increase the gas flow rates; this could be applied as a simulation of prebiotic chemistry during a volcanic eruption. The variety of products formed in these experiments is significantly greater than previously published and mimic the assortment of compounds detected in Murchison and CM meteorites.

  ROADMAP OBJECTIVES: 2.1 3.1 3.2 3.4 4.1 4.2 5.1 6.2 7.1 7.2

• Research Activities in the Astrobiology Analytical Laboratory

  A little over 4.5 billion years ago, our solar system was a disk of gas and dust, newly collapsed from a molecular cloud, surrounding a young and growing protostar. Today most of the gas and dust is in the spectacularly diverse planets and satellites of our solar system, and in the Sun. How did the present state of the planetary system come to be from such undistinguished beginnings? The telling of that story is an exercise in forensic science. The “crime” occurred a long time ago and the “evidence” has been tampered with, as most planets and satellites display a rich variety of geological evolution over solar system history.

  Fortunately, not all material has been heavily processed. Comets and asteroids represent largely unprocessed material remnant from the early solar system and they a represented on Earth by meteorites and interplanetary dust particles (IDPs). Furthermore, telescopic studies of the birth places of other solar systems allow researchers to simulate those environments in the laboratory so that we may characterize the organic material produced.

  We are a laboratory dedicated to the study of organic compounds derived from Stardust and future sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development. Like forensic crime shows, the Astrobiology Analytical Laboratory employs commercial analytical instruments. However, ours are configured and optimized for small organics of astrobiological interest instead of blood, clothing, etc.

  ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 7.1

• Untitled

  ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 4.1

• X-Ray Emission From an Intermediate-Mass Young Star, Protostar Binary System and Star-Forming Regions

  High-energy photons in the young stellar environment are known to be important in stimulating chemical reactions of molecules and producing pre-biotic materials that might later be incorporated into comets. Observational tests are sorely needed to assess the significance of such processing for Astrobiology and to guide development of theoretical models for chemical evolution in proto-planetary environments. We have observed X-ray emission from young low- and intermediate- mass stars mainly using the Chandra and XMM-Newton satellites, to understand the short-term X-ray variation and long-term activity evolution. In this reporting period, we studied X-ray and radio activities of individual stars in a binary protostar system and found no apparent connection between the X-ray and radio variability. We observed X-ray emission from the intermediate-mass young star MWC480, which showed stronger absorption than expected from far UV data.

  ROADMAP OBJECTIVES: 3.1

• Formation of Molecular Hydrogen via Interaction of Ionizing Radiation With Hydrocarbon Ices in the Interstellar Medium

  In the interstellar medium, the formation of molecular hydrogen is still
  unresolved. Various production mechanisms have been proposed.
  These involve a) dissociative recombination of H3+ with an electron, b)
  formation on grain surfaces, and c) formation in ices via interaction of
  cosmic ray particles. Here, we are conducting laboratory experiment to
  investigate to what extent cosmic ray particles can form molecular
  hydrogen upon interaction with ice-coated interstellar grain particles.
  The formation routes to be elucidated can be also exported to ices in
  our Solar system.

  ROADMAP OBJECTIVES: 3.1

• Mechanistical Studies on the Non-Equilibrium Chemistry of Unusual Carbon Oxide in Solar System Ices

  Higher carbon oxides of the form COn (n=3-8) have long been known as important molecules in atmospheric (Earth, Mars) and solid state chemical reactions. For instance, the CO3 molecule is considered as an important reaction intermediate in the atmospheres of Earth and Mars for quenching electronically excited oxygen atoms and in contributing to the anomalous 18O isotope enrichment. The geometry of the CO3 intermediate plays an important role in explaining these effects; however, only the cyclic (C2v) isomer has been experimentally confirmed prior to the project.

  ROADMAP OBJECTIVES: 2.2 3.1

• Modeling Grain Surface Reaction Pathways for Large Organic Molecules

  Interstellar ices show a varied composition with distinct water-rich and inert components consisting of a variety carbon-bearing species. Hydrogenation and oxidation reactions are equally important on the grain surface and drive most of the chemistry that occurs. Reactions involving carbon monoxide on the grain surface are known to be the dominant chemical pathways to many organic species like methanol and formaldehyde. Astronomical observations suggest that the larger organic species like ethanol and acetaldehyde are linked through successive hydrogenation of CO. However, the formation pathways (on the grain surface) of larger molecules like acetaldehyde and ethanol which form via formaldehyde and the efficiency of these pathways have not been determined. This aim of this project is model the pertinent grain surface reaction in order to assess the effectiveness of CO hydrogenation as the main pathway to more complex organic species.

  ROADMAP OBJECTIVES: 3.1

• Molecular Deuteration on Grain Surfaces

  n recent years, deuterium fractionation has been instrumental in deciphering the main chemical routes in molecular clouds. This fractionation reflects the small zero-point energy difference (a few hundred Kelvin) between deuterated species and fully hydrogenated species. At low temperatures, this can enhance the abundance of deuterium-bearing species by many orders of magnitude. In fact, recent observations of deuterated water have revealed that it is consistently less fractionated than other species by factors ranging from 10 to 100. Paralleling this, large deuterium fractionation effects are seen, most notably for deuterated forms of formaldehyde, methanol and ammonia versus their fully hydrogenated forms. Motivated by this, we have expanded our Monte Carlo accretion model to include deuterium chemistry in order to explore the role of grain surface chemistry in selectively deuterating ammonia and methanol as opposed to water.

  ROADMAP OBJECTIVES: 3.1

• Ultra-Violet Processing of Ices in the Rosette Nebula

  Dense clouds provide the natal molecular inventory for the formation of stars and planets. A serious caveat through is that the majority of the focus has been directed at clouds that are not analogous to the molecular cloud from which the solar nebula formed. The Sun formed in a high-mass star-forming cloud where at least one, and most likely manly, supernova event occurred resulting in intense ultra-violet radiation throughout the cloud complex. Understanding the nature of the material in our early solar nebula means understanding an environment dominated by massive stars. The Rosette molecular cloud provides the perfect laboratory analog for the early solar nebula molecular cloud. This project is a comparative study of the ultra-violet processing of the ices toward several embedded stellar clusters in the Rosette molecular cloud

  ROADMAP OBJECTIVES: 3.1

• Unveiling the Evolution and Interplay of Ice and Gas in Quiescent Clouds

  Molecular chemistry can provide insight into the physical processes at the earliest stages of starbirth, when molecular cloud cores collapse to form protostellar condensations. Dust particles in the dense clouds accrete molecules from the gas, resulting in the growth of ice mantles that eventually get transported into the protostellar environment. It is here, that the warm and dense environments of star forming regions promote a rich chemistry that creates complex prebiotic compounds and a small fraction of this ends up as planets. For these reasons, ice mantles in starless clouds (where harsh radiation does not affect the mantles) directly probe the dominant grain surface chemistry pathways and can be used as tracers of the origin of first generation ice molecules. This project is a comparative study of near-infrared, mid-infrared, and sub-millimeter spectral signatures of 35 discrete observations through the quiescent clouds LDN 673. Trends in the ice abundances can be studied exclusively as a function of cloud environment, such as the role of increasing extinction (dust column) in promoting grain surface chemistry.

  ROADMAP OBJECTIVES: 3.1