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Life in the Universe Projects (Continued)
“Analysis and Communication of Planetary Protection Issues for Solar System Missions”
Dr. Margaret Race
The work proposed under this grant includes research and activities that systematically analyze and communicate critical information about planetary protection (PP) to various audiences.The proposed work is the logical follow-on to a previous grant (NAG 2-6044) on “Addressing Issues in Planetary Protection and Mars Sample Return.” This project will continue to emphasize problem solving, decision making, and communication for solar system missions, including the planned Mars Sample Return (MSR) mission. Four areas of study continue to be important for future mission planning and implementation: 1) analysis of planetary protection issues and concerns associated with Mission Planning, NEPA Compliance and Public Decision Making; 2) Public Risk Perceptions associated with mission or related risks, 3) Risk Communication to varied audiences, especially via the mass media, and 4) Education and Public Outreach related to both Mars sample return and Astrobiology. The planned work encompasses research and analysis, communication of findings and information, as well as consulting services and Planetary Protection program support. The context of the overall work is related to NASA’s Astrobiology, Mars Exploration and Solar System Exploration programs and overall planning for human exploration of the solar system. The rationale for undertaking communication related research and activities on behalf of the planetary protection program is to ensure that communications relating to NASA programs and involving planetary protection are timely, accurate, clear, consistent, comprehensive and effective in the context of NASA’s ongoing public affairs, education and public outreach activities.
The PI’s research and activities emphasize the systematic examination and analysis of critical questions relating to planetary protection, and communication of information to both expert and lay audiences in appropriate formats and venues.The Co-I, Billings research and activities encompasses ongoing analysis of communications relating to planetary protection and the development, implementation, and assessment of a communication strategy and implementation plan for planetary protection.The objectives are to ensure that communication is an integral element of planning and implementation for NASA’s planetary protection program, to establish and implement a communication strategy that will advance the goals of the program, and to continuously improve communications relating to the program by monitoring, analysis, and assessment. Consulting activities under the grant provide support for the planetary protection program through research related to deep ocean, extreme environments. NASA Cooperative Agreement NNA04CC91G
“Active Atmospheres on Uranus and Neptune”
Dr. Kathy Rages
We propose Snapshot observations of Uranus and Neptune to monitor changes in their atmospheres on time scales of weeks, months, and years. Uranus is rapidly approaching equinox in 2007, with another 4 degrees of latitude becoming visible every year. Recent HST observations during this epoch (including 6818: Hammel, Lockwood, and Rages; 8680: Hammel, Rages, Lockwood, and Marley; 8634: Rages, Hammel, Lockwood, Marley, and McKay; and 10170: Rages, Hammel, Lockwood, and Marley) have revealed strongly wavelength-dependent latitudinal structure and the presence of numerous visible-wavelength cloud features in the northern hemisphere. Long-term ground-based observations (Lockwood and Thompson 1999) show seasonal brightness changes whose origins are notwell understood. Recent near-IR images of Neptune obtained using adaptive optics on the Keck Telesccope together with images from our Cycle 9 Snapshot program (8634) show a general increase in activity at south temperate latitudes as well as the possible development of another Great Dark Spot. Further Snapshot observations of these two dynamic planets will elucidate the nature of long-term changes in their zonal atmospheric bands and clarify the processes of formation, evolution, and dissipation of discrete albedo features.
HST-GO-10534.01-A
"Radiative Transfer Modeling of Planetary Atmospheric Structure"
Dr. Kathy Rages
The Hubble Space Telescope (HST) continues to produce spatially resolved images of the outer planets on a more-or-less yearly timescale, and is being joined by ground-based telescopes using adaptive optics to produce comparable (~0.1") spatial resolution in the near-infrared. Data from spacecraft such as Voyager, Galileo, and the various Mars orbiters and landers can still be exploited for very high spatial resolution and scattering geometries much different from any that can be observed from the vicinity of Earth.
This proposal is for work over a three year period to utilize the results of past and ongoing spatially resolved observations of planetary atmospheres to model the vertical structure of scatterers in some of those atmospheres, including latitudinal variations, discrete albedo features, and temporal changes on time scales of months and years. The work will include investigating the properties and vertical distribution of albedo features seen over a 12-year period in Neptune's atmosphere by both Voyager and HST, examining changes in Uranus' atmosphere which may be seasonal in origin, characterizing the properties of Jovian and saturnian stratospheric hazes seen by Galileo, Voyager, and HST, and including sunlight scattered by dust in the atmosphere of Mars in the determination of photometric properties for surface objects (rocks). NCC 2-1337
"Radiative Transfer Modeling of Planetary Atmospheric Structure"
Dr. Kathy Rages
The Hubble Space Telescope (HST) continues to produce spatially resolved images of the outer planets on a more-or-less yearly timescale, and is being joined by ground-based telescopes using adaptive optics to produce comparable (~0.1") spatial resolution in the near-infrared. Data from spacecraft such as Voyager and Galileo can still be exploited for very high spatial resolution and scattering geometries much different from any that can be observed from the vicinity of Earth, and Cassini is just beginning its multi-year mission in orbit around Saturn.
This project proposes, over a three year period, to utilize the results of past and ongoing spatially resolved observations of planetary atmospheres to model the vertical structure of scatterers in some of those atmospheres, including latitudinal variations, discrete albedo features, and temporal changes on time scales of months and years. The work will include investigating the properties and vertical distribution of albedo features seen over a 15-year period in Neptune’s atmosphere by both Voyager and HST, examining changes in Uranus’ atmosphere which may be seasonal in origin, and characterizing the properties of jovian and saturnian stratospheric hazes seen by Cassini, Galileo, Voyager, and HST. NNA05CS79A
"Isotopic Spectrometer for Astrobiology"
Dr. Todd Sauke
The overarching goal of this project is to collaborate with NASA personnel to define and carry out experiments to apply tunable diode laser technology to exobiological applications in molecular and isotopic analysis. A Stable Isotope Laser Spectrometer (the SILS instrument) is under development at NASA's Ames Research Center to measure isotopic ratios in gas samples, particularly Carbon-13 to Carbon-12 ratios in carbon dioxide gas. The project aims to explore and develop the applicability of tunable diode lasers for exobiological application on space flight missions to the surface of Mars. Isotopic analysis has proven very revealing in elucidating the nature and history of the biogenic elements on Earth and there are an abundance of important applications for isotopic measurements of biogenic elements on Mars. Martian studies present perhaps the most powerful and fruitful extra-terrestrial opportunity to study the evolution of life. Solid state tunable diode laser technology is inherently miniaturizable, requires little electrical power, and provides an ultra-high resolution, tunable, spectroscopic quality source for molecular and isotopic analysis in the important mid-infrared spectral region. Appropriate experimental protocols must be developed to apply this technology to space-flight and planetary applications of interest to NASA. In our laboratory, isotopic ratio measurements of carbon 13/12 using diode laser spectroscopy have been made with an accuracy of significantly better than 0.1 percent. This accuracy is sufficient for many important applications relevant to planetary, geological, and exobiological research and demonstrates the viability of the technique.
We have developed a bench-top model of a thermoelectrically cooled infrared laser source for spectroscopy and, in this project, we plan to continue the development of the thermoelectrically cooled laser spectroscopy source, improve the speed and efficiency of our instrument, and determine optimum trade-offs between science return and instrument design for a miniaturized version of the instrument. In previous related work, we assembled a versatile suite of prototyping hardware for spectroscopy which enables flexible application to a variety of experimental improvements and upgrades of measurement protocols as experimental conditions require and new ideas permit. We have extensive software libraries for data analysis and display and have gained expertise and experience with the technology and methodology to enable rapid progress on future project goals. The instrument concepts to be developed under this project will provide powerful tools for the investigation into how life developed in our solar system. NNA05CP99A
“Massive Star Formation and the Proper Motions of the OMC-1 Molecular Hydrogen Fingers"
Dr. Angela Schultz
In this project the NICMOS camera 2 will be used to re-image the molecular emission and associated continuum around Orion BN/KL, covering the region with 48 partially overlapping fields. All fields are located relative to a single fiducial position. Most locations in the region will appear in four different fields and all images have exactly the same orientation to facilitate combining all the measurements into a single, high precision image. These image swill be compared with previous NICMOS camera 2 and camera 3 line and continuum observations to measure small changes in position and morphology of the molecular hydrogen emission during the intervening period. The ultimate goal of this work is to measure position shifts as small as 0.25 pixels, 1-sigma – a level achieved in ground-based measurements of less complicated fields, but requiring considerable attention to detail as well as the stable repeatable point spread function of Hubble Space Telescope. HST–GO–10620.06
“Bioinformatics Facility for NASA”
Dr. Karl Schweighofer
Building on the existing prototype we propose to construct and field a facility with bioinformatics technologies that will help NASA meet its unique requirements for biological research. This facility will consist of a cluster of computers capable of performing computationally intensive tasks, software tools, databases and knowledge management systems. Novel computational technologies for analyzing and integrating new biological data and already existing knowledge will be developed. The facility will fulfill strategic NASA’s bioinformatics needs in astrobiology and space exploration. NNA05CV44A
"Planetary Rings: Observations and Interpretation"
Dr. Mark Showalter
This project addresses some of the fundamental open questions related to the dynamics and origins of planetary ring systems. We employ a variety of state-of-the-art techniques in image analysis and photometric modeling to glean untapped new information from the best existing spacecraft- and Earth-based data sets. The three systems to be studied encompass the full range of physical processes at work in planetary rings. (1) Continuing studies of the Voyager images of Saturn's F Ring will illuminate the dynamical processes behind its clumps, kinks and so-called "braids," providing context for recent Cassini results. We will study recently-identified brightness variations that appear to be an indicator of the clumps' collisional origins. We will also study periodicities and kinks in the ring to better define the role of nearby Prometheus and to search more thoroughly for the effects of Pandora and perhaps other nearby bodies. (2) We will take a new look at the question of whether unseen "shepherding" moons confine the rings of Uranus. We will use the best Voyager images to search for evidence of moons down to ~ 5 km in size, well below Voyager's widely quoted detection limit. We will also seek rotating modes and patterns in the rings, which could provide additional evidence for the resonant effects of nearby shepherds. (3) We will study the dynamics of dust in the Jovian ring system, using image analysis techniques that reveal more clearly the three-dimensional structure and photometric properties of the system. Analysis of Galileo, Voyager and Earth-based data, combined with dynamical simulations, will reveal the roles of non-gravitational processes including Poynting-Robertson drag and Lorentz resonances, and will help us to distinguish between rival models for dust evolution through the system. Key observations to explain are a newly-discovered ringlet of dust sharing its orbit with Amalthea and a discrepancy between the locations of dust and source bodies in the main ring. NNG05GL48G
"A Proposal to Relocate the Planetary Data System Rings Node to the SETI Institute"
Dr. Mark Showalter
The Planetary Rings Node is devoted to archiving and distributing scientific data sets relevant to planetary ring systems. The two major classes of ring data are images and occultation profiles, although a variety of additional data types (e.g. spectra, particle absorption signatures, etc.) are also of interest. A large fraction of our data sets are from the Voyager missions to the outer planets, but Earth-based and HST data sets are also represented. The Rings Node also performs a variety of services to support research into these data sets. These services include developing on-line catalogs and information systems, filling orders for data, developing software tools, and coordinating special observing campaigns.
The Planetary Rings Node supports research into all aspects of planetary ring systems, including their physical properties (particle sizes, composition, ring geometry), dynamical processes (including interactions with satellites) and origins. Indirectly, the Node also supports studies of other dynamical analogs such as the solar nebula and the asteroid belt, where similar physical processes are (or were) at work. In addition to supporting research, the Rings Node is committed to NASA's broader goal of educating the public about science and technology. The Rings Node is a cooperative project of SETI Institute, NASA Ames Research Center and the Center for Radar Astronomy at Stanford University. The PDS Rings Node has been relocated from NASA Ames Research Center to the SETI Institute in order to improve its on-line availability to the outside world. The PDS Rings Node had been located at NASA Ames since the PDS was first established in 1989. The PI has managed it since the very beginning and was recently re-selected to serve for another five years, 2004–2009. NNG05GI18G
"Rings of Uranus: Dynamics, Properties and Shepherding Moons"
Dr. Mark Showalter
This project consists of two observing programs running on the Hubble Space Telescope, focusing on the ring systems of Uranus and Neptune. Uranus has a set of narrow rings and a family of 13 nearby moons. Our Uranus observations in August 2003 discovered the two smallest of these moons, currently designated S/2003 U 1 and S/2003 U 2. Both bodies are only a few miles across, perhaps the size of San Francisco. It is a testament to the remarkable capabilities of the Hubble telescope that we are able to see bodies from Earth that were too small to be detected by Voyager's cameras during the 1986 flyby. Our work on Neptune's ring system is just beginning but our first observations clearly show its mysterious arcs, incomplete rings that have held together for at least 20 years now. HST–GO–10102.03
“Transcending Voyager: A Deeper Look at Neptune’s Ring-Moon System”
Dr. Mark Showalter
We will use the High Resolution Channel (HRC) of ACS to study the inner rings, arcs and moons of Neptune with a sensitivity that exceeds that achieved by Voyager 2 during its 1989 flyby. Our study will reveal any moons down to V magnitude 25.5, to address a peculiar truncation in the size distribution of inner moons and to look for the "shepherds" and source bodies for Neptune's dusty rings. (For comparison, Neptune's smallest known moon is Naiad, at magnitude 23.9). Recent ground-based studies show that the mysterious arcs in the Adams Ring continue to shift and change, and may be fading away entirely. We will obtain the visual-band data uniquely necessary to determine whether the arcs are fading. Long-term monitoring of the arcs at high resolution and sensitivity will reveal their gradual changes more clearly and enable us to assess the role of Galatea, whose resonances are widely believed to confine the arcs. HST-GO-10398.01
"The Interaction of Stars with the Interstellar Medium: Infrared Studies with SOFIA"
Dr. Janet Simpson
This project is a continuation of a collaboration with personnel at NASA/Ames Research Center, which involves research on a number of topics: (1) the formation and evolution of young stars, the interaction of the radiation and mass outflows from these stars with the surrounding interstellar medium, and the accretion disks and natal cocoons surrounding the newly formed stars, which might be the site of planet formation, (2) the centers of galaxies, both those actively forming stars and those whose extreme radiation fields prevent the local formation of the cold clouds out of which stars are formed, (3) the production and return of heavy elements to the interstellar medium in supernova explosions and mass loss from aged stars, and the results of such enrichment on the chemical evolution of the Galaxy, and (4) in order to further research on these topics, activities involved with the construction and use of a new telescope for airborne infrared astronomy: SOFIA-the Stratospheric Observatory For Infrared Astronomy.
The Principal Investigator is an astronomer involved in research at both near-infrared and far-infrared wavelengths concerning the formation of young stars, the evolution of both old and young stars, which brings about the return of chemically enriched material to the interstellar medium, the interstellar medium in which these objects are embedded, and manifestations of both starbursts and active galactic nuclei in galaxies. While the end product of this study can and will be used in a wide variety of ways, we envision using this information to examine the processes of star formation, critical to understanding the likelihood of planet formation, and the evolution of the interstellar medium, including the formation of the complicated molecules that are essential to the formation of life. NCC 2-1367
"The Interaction of Stars with the Interstellar Medium of Galaxies"
Dr. Janet Simpson
In collaboration with personnel at NASA Ames Research Center this project involves research on a number of topics: (1) the formation and evolution of young stars, the interaction of the radiation and mass outflows from these stars with the surrounding interstellar medium, and the accretion disks and natal cocoons surrounding the newly formed stars, which might be the site of planet formation, (2) the centers of galaxies, both those actively forming stars and those whose extreme radiation fields prevent the local formation of the cold clouds out of which stars are formed, and (3) the production and return of heavy elements to the interstellar medium in supernova explosions and mass loss from aged stars, and the results of such enrichment on the chemical evolution of galaxies.
The Principal Investigator, Dr. Simpson, is a Ph.D. astronomer involved in research at both near-infrared and far-infrared wavelengths concerning the formation of young stars, the evolution of both old and young stars, which brings about the return of chemically enriched material to the interstellar medium, the interstellar medium in which these objects are embedded, and manifestations of both starbursts and active galactic nuclei in galaxies. She will be assisted by Dr. Angela Cotera, also of SETI Institute, who is an expert on the massive stars and clusters of massive stars that are seen in the center of the Milky Way Galaxy. While the end product of this study can and will be used in a wide variety of ways, SETI Institute envisions using this information to examine the processes of star formation, critical to understanding the likelihood of planet formation, and the evolution of the interstellar medium, including the formation of the complicated molecules that are essential to the formation of life. NNA05CS33A
"Detection of Complex, Electromagnetic Markers of Technology"
Dr. Richard Stauduhar
We propose to extend work of the PI and CO-I that developed widely used methods for detecting simple signal types characteristic of our civilization 1,2. These signals, if present in other stellar systems, are highly distinguishable markers of an advanced biology, one that has produced intelligent electromagnetic signals. As our civilization’s communication technology has evolved, demands for efficient use of the electromagnetic spectrum has resulted in an ever- higher proportion of signals with complex forms of encoding 2. Thus, the ensemble of terrestrial signals today consists of both “simple” signals, ones with well defined prominent characteristics, and complex signals, those spread in frequency and time. If this proposed development leads to effective discriminators for complicated signals, we will use prototype and advanced instruments to complement current detection of simple signal types. This will be demonstrated using complex discriminators combined with detectors for simple signals on a telescope of advanced design, the Allen Telescope Array (ATA). Thus, the biomarkers of advanced technology may be simultaneous detection of a collection of simple and complex signals originating from a planet orbiting a Sun-like star.
In general, the search for extraterrestrial intelligence (SETI) is a search for technology orbiting distant stars. If the Earth is typical, the most striking electromagnetic evidence of technology may well be microwave signals, which can, over their transmission frequencies, outshine stars by a factor of a million. This is because our signals contain strong, concentrated components, and because stars transmit most of their energy in the visible region, not the microwave region, of the electromagnetic spectrum. NNG05GM93G
“Development of Techniques for, and the Analysis of, Biogeochemical Sample”
Dr. David P. Summers
This work will support the analysis of samples and the development of techniques to analyze samples for NASA objectives. It covers two main thrusts. The development of techniques and data for the analysis of samples of astrobiological interests, from samples returns, to analysis of exogenous materials, to the detection of life and proteins, to the detection of microbial activity in extreme environments. The other thrust is to support the characterization of biogeological materials to better understand early life on Earth, its context, how it impacted the planet, and how it evolved. This will involve both the analysis of biogeological samples collected in field and also samples produced by abiotic reactions (as a benchmark to compare samples of suspected biogenic origin against). NASA Cooperative Agreement NNA04CK54A
"Geochemistry and Mineralogy of Atacama Desert Soils: A Possible Mars Soil Analog"
Dr. Brad Sutter
The geochemistry and mineralogy of Atacama Desert soils is being examined in order to understand sulfur and chlorine, and possible carbonate and nitrate, abundance and distributions in Mars soils, and their relation to soil water activity. The soil formation mechanisms operating in the Atacama that have led to the presence of carbonate and the accumulation of nitrate, sulfate, and chloride in the Atacama soils are being determined. Soil sampling sites will be selected in the Atacama Desert from 24 o S to 27 oS along an arid humid gradient corridor. By choosing soils along the arid-humid gradient, changes in soil properties will be examined as a function of climate. Soils toward the south receive ~15 mm y -1 while soils towards the north receive 2 mm decade -1
Total chemical analyses of soil and rock at the Atacama soil sites will include Si, Al, Fe, Mn, Ca, Mg, K, Na, Zr, Cl, Ti, C, S, nitrate-N, ammonium-N, and inorganic C (carbonate). Mass-balance determinations of selected elements (e.g., Si, Al, S, and Cl) combined with soil strain analyses will provide further information regarding the extent and nature of geochemical weathering processes and soil volume changes that have occurred with soil development in the Atacama (Brimhall and Dietrich, 1987; Chadwick et al., 1990). The mineralogy of each soil sample along with surface rock material will be analyzed by X-ray diffraction (XRD). Mineralogical analyses will indicate what degrees of aqueous activity the soils have experienced. NNA05CS54A
"Allen Telescope Array"
Dr. Jill Tarter
It's one of the most persistently enticing sirens to beckon the SETI community: a major telescope that can be dedicated to the search. Despite the seductiveness of this idea, construction of an instrument designed to meet the requirements of full-time SETI has always foundered on the large costs.
In the next few years, that situation is going to change. Thanks to the far-sighted benevolence of technologists Paul Allen (co-founder of Microsoft) and Nathan Myhrvold (former Chief Technology Officer for Microsoft), a new telescope will be constructed that will allow a targeted SETI search to proceed 24 hours a day, 7 days a week.
The new instrument, now called the Allen Telescope Array, was known formerly as the One Hectare Telescope, or 1hT, is a joint effort by the SETI Institute and the University of California, Berkeley. Because of its novel construction-an array of inexpensive antennas-it can be simultaneously used for both SETI and cutting-edge radio astronomy research. Pending state and federal permitting, it will be built at the existing Hat Creek Observatory, run by the Radio Astronomy Lab at Berkeley, and located in the Cascades just north of Lassen Peak (California). The construction cost will be $26 million. The donors have given approximately half of this money to the Institute now to underpin continued tests of the technology intended to establish the instrument's final design parameters.
"Evaporating Grains in Reflection Nebulae"
Dr. Pasquale Temi
ISOCAM spectral data of Ced 201 indicate that there is a component underlying the PAH bands that Cesarsky et al. (2000) have attributed to emission from very small carbonaceous grains (VSGs). These grains would not be the classical small silicate grains observed in the interstellar medium and HII regions, but amorphous carbon particles PAH clusters that could comprise the smallest of the interstellar grains. Very small carbonaceous grains with some aromaticity have been suggested as contributors to the interstellar extinction curve, but have never been directly confirmed. Cesarsky et al. also suggest that close to the exciting star of the nebula, PAH molecules are either liberated from the VSGs, or the VSGs are aromaticized by the UV from the central star. Their observations show that the 7.7 band appears to get broader towards the edges of the nebula, as expected if the PAHs are in clusters, but the ISOCAM data do not have sufficient spectral resolution (about 40) to determine if the apparent broadening is due to multiple components or true broadening of the feature. We propose to study the emission as a function of position in Ced 201 and two other morphologically similar reflection nebulae at the higher spectral resolution of the Spitzer IRS and at longer wavelengths than was possible with ISOCAM to determine:
1. whether the apparent broadening of the 7.7 micron band is due to intrinsic broadening or to separate components that vary in relative strength as a function of distance from the star.
2. whether the other PAH emission bands, particularly the 11.3 micron band, broaden as well, as expected if the PAHs exist as clusters or VSGs.
3. whether the temperature of the continuum decreases with distance from the star (as for classical VSGs), maintains a constant value as for grains small enough to see just single photon events, or whether it is a combination of the two.
4. if VSGs are present, the size of the VSGs required to produce the observed continuum. JPL1276019
"The Origin and the Evolution of Dust in the Hot Interstellar Gas of Elliptical Galaxies"
Dr. Pasquale Temi
Detection of elliptical galaxies at 60 and 100 microns with the IRAS satellite showed conclusively that these galaxies contain truly interstellar dust, which is mixed into hot interstellar gas at the virial temperature, typically 10e7 K. Dust grains in this harsh environment are progressively destroyed by collisions with thermal protons that dislodge atomic fragments from the grain surface (sputtering). However, as the dust grains are slowly reduced in size, they are heated both by UV stellar radiation from post-AGB stars and by inelastic collisions with thermal electrons and this energy is radiated in the far-IR. New dust grains are continuously injected into the interstellar gas by dusty stellar winds from red giant stars. Dusty stellar winds are verified by mid-IR observations of ellipticals where the emission follows a de Vaucouleurs stellar profile. The total far-IR emission from internally produced grains during their sputtering lifetime is roughly consistent with the far-IR luminosities observed so far, but large discrepancies between expectation and observation have recently become evident. For example, in one giant Virgo elliptical the far-IR emission observed with ISO is about 40 times larger than expected, while another similar Virgo elliptical was undetected. The detected galaxy may have recently received a contribution of new dust from a merger with a gas-rich galaxy, but the merger must have been very recent indeed since the dust destruction time is only about 10e8 years. We propose to observe a small number of nearby spatially-resolved and optically luminous elliptical galaxies with SPITZER in order to calibrate our theoretical models of dust creation, destruction and radiation. In addition we wish to evaluate the alternative hypothesis that mergers are an important source of interstellar dust. Almost nothing is currently known about the radial distribution of far-IR emission from ellipticals, but we expect SPITZER to change this soon. JPL1276823
"PAHs in the Diffuse ISM"
Dr. Pasquale Temi
Our understanding of the IR emission features and their carriers (PAHs) is almost exclusively based upon spectral studies of bright HII regions and planetary nebulae. In contrast, while PAHs spend most of their lives cycling between the diffuse ISM and dark clouds, very little is known about the comparatively weak IR emission spectrum of the diffuse ISM. One of the major discoveries of IRAS was the widespread presence of cirrus emission at mid-IR wavelengths throughout the diffuse ISM, but IRAS was unable to characterize this emission further, and more recent studies using the IRTS and ISOPHOT did not produce spectra of sufficient quality for meaningful comparisons with other types of sources (Onaka et al. 1996; Mattila et al. 1996). We propose to measure the IR emission spectrum of the diffuse ISM along well studied lines of sight towards diffuse translucent clouds, of bright cirrus clumps, and of reflection nebulae. This will provide a census of low to mid density and UV field intensities that can be compared to existing Spitzer/ISO data of regions with high density and high UV field intensity (i.e. HII regions and planetary nebulae). The questions we will address are:
1. What is the mid-IR spectrum of the diffuse ISM?
2. How does the spectrum of the mid-IR emission spectrum depend on the local physical conditions (density, UV field) ?
3. How do the spectra of the diffuse ISM (low density, low UV field) compare to the spectra of reflection nebulae (intermediate conditions) and to those of HII regions and reflection nebulae (high density, high UV field)?
The proposed observations will provide direct information on the abundance and ionization state of PAHs in the diffuse ISM. JJPL1276015
“Study of the ISM in our own Galaxy and the Dust Emission in Early-type Galaxies”
Dr. Pasquale Temi
The purpose of this research is to use the large database of observations taken by the ISO satellite and data that will be soon available from SOFIA and SIRTF to study the ISM of our own and external galaxies. The project is split into two separate tasks : Study how PAHs respond to changes in UV illumination and how their emission spectrum changes in reflection nebulae; we will use clustering techniques applied to spectral-spatial data cubes to group regions with similar spectra. Clustering uncovers the underlying geometry of the nebula, and reduce the number of spectra from each object to a manageable number. We use the Ames Astrochemistry Laboratory PAH database to determine the ion to neutral ratio, and compare the results with theoretical calculation.
Detect and characterize the dust emission in early-type galaxies. We investigate and address the following scientific issues: 1) Map the distribution of the dust (warm and cold dust components) in and around early-type galaxies located in the field, groups and rich clusters. 2) Derive the physical properties of the dust, such as temperature and mass. 3) Determine how hot interstellar gas affects the size distribution of dust grains and their total mass.4) Investigate the proposition that dust is continuously formed and destroyed in cooling flows. 5) Test the hypothesis that some of the dust may have an external origin.
This program is comprised of observational and theoretical projects and the work is done in collaboration with observational and theoretical astronomers both at NASA Ames Research Center and at the University of California Santa Cruz. NASA Cooperative Agreement NCC 2–1417
"Prebiotic Synthesis of Autocatalytic Products from Formaldehyde-Derived Sugars as the Carbon and Energy Source"
Dr. Arthur Weber
In a general way, life could be described as a chemical process (metabolism-biopolymer synthesis) that is catalytically controlled by its products (proteins-nucleic acids) in a way that enhances the perpetuation of the entire system. From this perspective, the origin of life can be considered as a series of events in which a prebiotic chemical process became increasingly controlled by the catalytic action of its products in a way that facilitated self-perpetuation. This view stressing autocatalysis imposes three constraints on the chemical process responsible for the origin of life. The process must (a) yield autocatalytic products that accelerate their own synthesis, (b) be a 'one-pot’ process where proximity and containment allow catalytic products to act on chemical intermediates of the process, and (c) occur in the presence of liquid water needed for delivery of a primary organic substrate(s) from the environment. Furthermore, the process must have a favorable free energy, and a rate that is faster than the rate of loss of intermediates from the catalytic domain. The relevance of the process to biogenesis is strengthened if its chemistry resembles and thereby allows its straightforward development into modern metabolism. Based on these criteria, we currently believe that the most attractive process for the origin of life involves sugar chemistry, specifically the incorporation of formaldehyde and/or glycolaldehyde into acyclic sugars that then react with ammonia and/or hydrogen sulfide to generate a variety of autocatalytic products (amines, amino acids, imidazoles, thiols, and polymers). Therefore, we propose to investigate this chemical process named the Sugar Model in order to develop a better understanding of the chemical dynamics involved in the origin of life on the early Earth and elsewhere. This proposed model study of the origins process is aimed at (a), understanding how life begins and evolves by identifying the sources of simple chemicals that contribute to prebiotic evolution and the emergence of life, and (b) determining which chemical systems could have served as precursors of metabolic and replicating systems on Earth and elsewhere, including alternatives to the current DNA-RNA-protein basis for life. NASA Cooperative Agreement NNA05CP68A
“Electrification of the Clouds of Planets”
Dr. Robert Whitten
The charging of aerosol particles in planetary atmospheres is important in that free electrons produced by galactic cosmic rays (GCR) and (at high altitudes) by electrons precipitating from magnetospheres (if present) attach to the particles; this process can lead to the occurrence of lightning and the production of complex molecules of significance to the origins of life. Similar arguments concerning the occurrence of lightning on the dayside, where the particles are positively charged, also hold true. An earlier study (Borucki et al, 1987) using a much less sophisticated model led to preliminary results for the night side of Titan. A much more sophisticated model that simulates such effects has been developed and has yielded preliminary results for both the dayside and night side of Titan. Models are being investigated for Jupiter and Mars and well as for Titan. NASA Cooperative Agreement NNA04CC64A
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