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2012 Annual Science Report

Astrobiology Roadmap Objective 1.1 Reports Reporting  |  SEP 2011 – AUG 2012

Project Reports

  • Biosignatures in Ancient Rocks

    The Biosignatures in Ancient Rocks group investigates the co-evolution of life and environment on early Earth using a combination of geological field work, geochemical analysis, genomics, and numerical simulation.

    ROADMAP OBJECTIVES: 1.1 3.2 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Project 1: Interstellar Origins of Preplanetary Matter

    Interstellar space is rich in the raw materials required to build planets and life, including essential chemical elements (H, C, N, O, Mg, Si, Fe, etc.) and compounds (water, organic molecules, planet-building minerals). This research project seeks to characterize the composition and structure of these materials and the chemical pathways by which they form and evolve. The long-term goal is to determine the inventories of proto-planetary disks around young sun-like stars, leading to a clear understanding of the processes that led to our own origins and insight into the probability of life-supporting environments emerging around other stars.

  • Project 1: Looking Outward: Studies of the Physical and Chemical Evolution of Planetary Systems

    This project integrates the work of Carnegie Institution Astronomers in the 1) the search for extrasolar planets, 2) understanding the flow of matter in protoplanetary disks around young stars, 3) understanding the origin of Near Earth Objects, in particular, their relationship with objects in the asteroid belt, and 4) understanding the composition of disks around young stars and the potential delivery of volatiles to terrestrial planets in other solar systems.

    ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1
  • Cosmic Distribution of Chemical Complexity

    The three tasks of this project explore the connections between chemistry in space and the origin of life. We start by tracking the formation and evolution of chemical complexity in space, from simple carbon-rich molecules such as formaldehyde and acetylene to complex species including amino acids, nucleic acids and polycyclic aromatic hydrocarbons. The work focuses on carbon-rich species that are interesting from a biogenic perspective and on understanding their possible roles in the origin of life on habitable worlds. We do this by measuring the spectra and chemistry of analog materials in the laboratory, by remote sensing with small spacecraft, and by analysis of extraterrestrial samples returned by spacecraft or that fall to Earth as meteorites. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.4 4.3 7.1 7.2
  • Astrobiological Exploration of Mars

    MIT Team member John Grotzinger is the Project Scientist of the MSL mission currently underway at Gale Crater on Mars. John, and his team at Caltech, led a major study of potential landing sites which resulted in the selection of Gale Crater. Since then, they have been involved in the Gale Imaging Working Group, which has been identifying key HiRISE and CRISM data products, which will enhance the science mission. Several members of the Grotzinger group have also been involved in creating a geologic map of the landing site. This involves mapping 1.5° square quads in the landing ellipse and nearby areas. Since landing, the mapping focus has shifted from compiling a regional map to understanding the details of the units and geological relationships in the immediate vicinity of Curiosity.

  • Habitability of Icy Worlds

    Habitability of Icy Worlds investigates the habitability of liquid water environments in icy worlds, with a focus on what processes may give rise to life, what processes may sustain life, and what processes may deliver that life to the surface. Habitability of Icy Worlds investigation has three major objectives. Objective 1, Seafloor Processes, explores conditions that might be conducive to originating and supporting life in icy world interiors. Objective 2, Ocean Processes, investigates the formation of prebiotic cell membranes under simulated deep-ocean conditions, and Objective 3, Ice Shell Processes, investigates astrobiological aspects of ice shell evolution.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.3 3.4 4.1 5.1 6.1 6.2 7.1 7.2
  • Astrophysical Controls on the Elements of Life, Task 1: High-Precision Isotopic Studies of Meteorites

    The initial Solar System abundances of the short-lived radionuclides (SLRs) 26Al (half life ~0.73 Ma) and 60Fe (half life ~2.6 Ma) are important to constrain since, if present in sufficient abundance, these SLRs served as heat sources for dehydration and differentiation processes on planetary bodies. The implications for this work include the astrophysical environment in which the Sun formed, and the abundance of water on the terrestrial planets.

  • Astrophysical Controls on the Elements of Life, Task 2: Model the Chemical and Dynamical Evolution of Massive Stars

    Stars create the chemical elements heavier than hydrogen and helium, with the majority arising from the lives and violent deaths of massive stars in supernova explosions. The starting chemical composition of stars also affects their evolution and that of their associated planets. We have performed computational simulations for a large range of stellar masses to provide predictions for important stellar characteristics (i. e. brightness, temperature, stellar winds, composition) over the stars’ lifetimes and made the data available to the public. We have also simulated the explosions of massive stars to predict the chemical abundances of material ejected from the dying stars and how that material is distributed in the surrounding universe. As a complement, we are finding the chemical abundances of hundreds of nearby, potentially habitable stars and modeling how the habitable zones and planets of stars with different abundances evolve.

  • Aqueous Alteration of CR Chondrites

    Petrologic studies of chondrites have shown that many samples contain hydrated minerals that are formed by aqueous alteration of primitive components. Through this discovery, it has become clear that the action of water played a key role in geologic processes of the early Solar System. CR chondrites – a subclass of carbonaceous chondrites – display a range of mineralogy from practically anhydrous (type 3) to completely hydrated (type 1). In addition, CRs show minimal evidence for thermal metamorphism that overprints or obscures aqueous alteration signatures. Knowledge of the aqueous alteration in CR chondrites will yield important interpretations on how, and to what extent, water affected the geologic evolution of primary nebular components, with implications that extend to how and where life began to evolve in the Solar System. A particularly important issue is how aqueous alteration affected the initial set of organic compounds present in carbonaceous chondrites. Amino acids (the building blocks of life) are a class of organic molecule present in meteorites. Understanding how or if organic molecules form on meteorites and their interactions with the water in meteorites has important implications for the chemical inventory of the meteorites, the process by which life formed on our planet, and the possibility that life can form on other planets in our Solar System. We are using a suite of micro analytical tools to understand the early solar system aqueous environment and production or organic material.

  • Disks and the Origins of Planetary Systems

    This task is concerned with the formation and evolution of complex habitable environments. The planet formation process begins with fragmentation of large molecular clouds into flattened disks. This disk is, in many ways, an astrochemical “primeval soup” in which cosmically abundant elements are assembled into increasingly complex organic compounds and mixed in the dust and gas within the disk. Gravitational attraction among the myriad small bodies leads to planet formation. If the newly formed planet is a distance from its star that is suitable to support liquid water at the surface, it is in the so-called “habitable zone” (HZ). The formation process and identification of such life-supporting bodies is the goal of this project.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.3
  • Project 2: Processing of Precometary Ices in the Early Solar System

    The discovery of numerous planetary systems still in the process of formation gives us a unique opportunity to glimpse how our own solar system may have formed 4.6 billion years ago. Our goal is to test the hypothesis that the building blocks of life were synthesized in space and delivered to the early Earth by comets and asteroids. We use computers to simulate shock waves and other processes that energize the gas and dust in proto-planetary disks and drive physical and chemical processes that would not otherwise occur. Our work seeks specifically to determine (i) whether asteroids and comets were heated to temperatures that favor prebiotic chemistry; and (ii) whether the requisite heating mechanisms operate in other planetary systems forming today.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Delivery of Volatiles to Terrestrial Planets

    We are investigating the mechanisms by which terrestrial planets obtain water and organic compounds. By understanding how these crucial constituents for life came to Earth, we can determine whether these mechanisms also operate in exoplanetary systems. When an earth-like planet is finally discovered in an exoplanetary system, it will be difficult to directly measure the composition of that planet. However, VPL scientists will use the observable properties of the system to determine whether that planet has a history that allowed water and organics to have been transported to it. One of the important questions is the initial state of the organic compounds, which sets stringent limits on the ability of the earth-like planets to acquire carbon.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 4.1 4.3
  • Biosignatures in Extraterrestrial Settings

    Exploring the prospects for biosignatures in extraterrestrial settings is a multi

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 4.1 4.3 6.2 7.1 7.2
  • Astrophysical Controls on the Elements of Life, Task 3: Model the Injection of Supernova Material Into Star-Forming Molecular Clouds

    The goal of this task is to see if material ejected from a star that has exploded as a supernova can make its way into the gas as it is forming new solar systems. It has been expected that this material, because it is moving so fast (> 2000 km/s) when it hits the cold, dense molecular cloud in which stars are forming, would shock, heat up, and then “bounce” off of the cloud boundary. Our numerical modeling using state-of-the-art numerical codes and thousands of computers at the Arizona Center for Advanced Computing, shows that the gas can in fact cool quickly enough to penetrate into the molecular cloud. Stars can be contaminated with supernova material just as they are forming, at contamination levels consistent with isotopic and chemical evidence from meteorites.

  • Project 3: The Origin, Evolution, and Volatile Inventories of Terrestrial Planets

    Project 3 focuses on understanding the nature of volatiles (principally water and gase like carbon dioxide and methane) in planetary interiors. The origin of Earth’s oceans and the initiation of plate tectonics may have related through the retention of water deep in Earth’s mantle. In this project scientists study how volatiles behave in silicate melts and Earth’s deep interior. They also study other rock planets, e.g. Mars and Mercury to understand how the presence or absence of volatiles may have lead to such disparate outcomes relative to Earth.

    ROADMAP OBJECTIVES: 1.1 3.1 4.1
  • Detectability of Biosignatures

    In this project VPL team members explore the nature and detectability of biosignatures, global signs of life in the atmosphere or on the surface of a planet. This year we submitted for publication modeling work that explores the potential for non-biological generation of oxygen and ozone in early Earth-like atmospheres, which could result in a “false positives” for photosynthetic life. In parallel, we worked with three simulators for telescopes that will one day be able to observe and determine the properties of extrasolar terrestrial planets, and used these simulators to calculate the relative detectability of gases produced by life.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 7.2
  • Astrophysical Controls on the Elements of Life, Task 4: Model the Injection of Supernova Material Into Protoplanetary Disks

    The goal of this project is to determine whether supernova material could be injected into a protoplanetary disk, the disk of gas and dust from which planets form. A secondary issue is whether these materials would be mixed within the disk efficiently, and whether such an injection into our own protoplanetary disk can explain the isotopic evidence from meteorites that the solar system contained short-lived radionuclides like 26Al.

  • Detection of Circumbinary Planets Using Kepler Space Telescope

    Observations of stars in our galaxy have indicated that more than 60% of stars are in binaries or clusters. Several of these binary systems have been found to host circumbinary debris disks, suggesting that planet formation may proceed successfully around the entire binary system. During the past year, the PI teamed up with the Kepler Science Team to look for circumbinary planets. Their search has resulted in the discovery of three of such planets in 2012.

  • Path to Flight

    The (Field Instrumentation and) Path to Flight investigation’s purpose is to enable in-situ measurements of organics and biological material with field instrumentation that have high potential for future flight instrumentation. The preceding three Investigations (Habitability, Survivability and Detectability) provide a variety of measurable goals that are used to modify or “tune” instrumentation that can be placed in the field. In addition the members involved with Investigation provide new measurement capabilities that have been developed with the specific goal of life-detection and organic detection using both non-contact/non-destructive means and ingestion based methods. The developments under this investigation (Inv 4) incorporate state-of-the-art laboratory instruments and next generation in-situ instrumentation that have been developed under programs that include NASA as well as NSF and DOD. These include mass-spectrometers, gas analyzers, and fluorescence/Raman spectrometry instruments.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 7.1 7.2
  • Dynamical Effects on Planetary Habitability

    The Earth’s orbit is near-circular and has changed little since its formation. The Earth is also far enough away from the Sun, that the Sun’s gravity doesn’t seriously affect the Earth’s shape. However, exoplanets have been found to have orbits that are elliptical, rather than circular, and that evolve over time, changing shape and/or moving closer or further to the parent star. Many exoplanets have also been found sufficiently close to the parent star that it can deform the planet’s shape and transfer energy to the planet in a process called tidal heating. In this VPL task we investigate how interactions between a planet’s orbit, spin axis, and tidal heating can influence our understanding of what makes a planet habitable. Scientific highlights include modeling of habitable planets around brown dwarfs, the first comprehensive analysis of exomoon habitability, the role of distant stellar companions on planetary system architecture, and an improved understanding of the origins of terrestrial planet composition.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 4.3
  • Project 4: Survival of Sugars in Ice/Mineral Mixtures on High Velocity Impact

    Understanding the delivery and preservation of organic molecules in meteoritic material is important to understanding the origin of life on Earth. Though we know that organic molecules are abundant in meteorites, comets, and interplanetary dust particles, few studies have examined how impact processes affect their chemistry and survivability under extreme temperatures and pressures. We are investigating how impact events may change the structure of simple sugars, both alone and when combined with ice mixtures. The experiments will allow us to understand how sugar chemistry is affected by high pressure events and to contrast the survival probabilities of sugars in meteorite and comet impacts. This will lead to a better understanding of how organic molecules are affected during their delivery to Earth. This project leverages expertise in two different NAI nodes, increasing collaborative interaction among NAI investigators.

    ROADMAP OBJECTIVES: 1.1 3.1 4.1 4.3
  • Project 5: Vistas of Early Mars: In Preparation for Sample Return

    To understand the history of life in the solar system requires knowledge of how hydrous minerals form on planetary surfaces, and the role minerals may play in the development of potential life forms. The minerals hematite and jarosite have been identified on Mars and presented as in situ evidence for aqueous activity. This project seeks to understand (i) the conditions required for jarosite and hematite formation and preservation on planetary surfaces, and (ii) the conditions under which their “radiometric clocks” can be reset (e.g., during changes in environmental conditions such as temperature). By investigating the kinetics of noble gases in minerals, known to occur on Mars and Earth, we will be prepared to analyze and properly interpret ages measured on samples from future Mars sample return missions.

    ROADMAP OBJECTIVES: 1.1 2.1 7.1
  • Determining the Age and Nature of Asteroid Aqueous Alteration

    Scientists who model thermophysical, chemical and dynamical properties of small bodies base their parameters on the understanding that minerals like fayalite (Fe2SiO4, with trace Mn and Cr) formed by aqueous (water) alteration within the asteroid. Our studies of rock textures and isotopic data are consistent with fayalite forming during aqueous alteration. We are using oxygen isotopes to define the oxygen-isotope composition of the asteroidal water, and Mn-Cr isotopes to determine when the mineral formed.

    Our results show that fayalite-bearing assemblages formed in situ, during fluid-rock interaction at low water-to-rock ratios and temperatures below 300°C. The 53Mn-53Cr chronometry investigation requires standards of appropriate composition, so we have created synthetic fayalite under known temperature and oxygen fugacity controlled by mixtures of H2 and CO2. Future chronometry investigations will use these well-characterized standards when analyzing meteoritic fayalites from different parent bodies. The combination of O and Mn-Cr isotopic data will be used to constrain the nature and timing of key water-related processes within the early Solar System.

  • Astrophysical Controls on the Elements of Life, Task 5: Model the Variability of Elemental Ratios Within Clusters

    This project aims to better understand the self-enrichment that goes on in star-forming molecular clouds as stars near the end of their lives and deposit heavy elements into the surrounding medium, where other stars are still in the midst of forming. Through detailed hydrodynamic simulations we are studying the mixing of heavy elements and its relation to variable abundance ratios in present-day clusters, as well as the transition from pristine to enriched star formation in the early universe.

  • Planetary Surface and Interior Models and SuperEarths

    We use computer models to simulate the evolution of the interior and the surface of real and hypothetical planets around other stars. Our goal is to work out what sorts of initial characteristics are most likely to contribute to making a planet habitable in the long run. Observations in our own Solar System show us that water and other essential materials are continuously consumed via weathering (and other processes) and must be replenished from the planet’s interior via volcanic activity to maintain a biosphere. The surface models we are developing will be used to predict how gases and other materials will be trapped through weathering over time. Our interior models are designed to predict how much and what sort of materials will come to a planet’s surface through volcanic activity throughout its history.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 5.2 6.1
  • Project 6: The Environment of the Early Earth

    This project involves the development of capabilities that will allow scientists to obtain information about the conditions on early Earth (3.0 to 4.5 billion years ago) by performing chemical analyzes of crystals (minerals) that have survived since that time. When they grow, minerals incorporate trace concentrations of ions and gaseous molecules from the local environment. We are conducting experiments to calibrate the uptake of these “impurities” that we expect to serve as indicators of temperature, moisture, oxidation state and atmosphere composition. To date, our focus has been mainly on zircon (ZrSiO4), but we have recently turned our attention to quartz as well.

    ROADMAP OBJECTIVES: 1.1 4.1 4.3
  • Geochemical Signals for Low Oxygen Worlds

    We are studying the physiology of sulfate reducing bacteria, organisms that perform a key microbial metabolism in anoxic worlds. By calibrating microbial sulfur isotope effects, we can infer the redox level of paleoenvironments in the geologic past by studying sedimentary records. The sulfur cycle is intimately linked to the redox budget of the Earth’s surface, such that this study will help inform us about the evolution of aerobic environments, a key process that set the stage for animal evolution. Similarly, we also are studying the role of oxygen in controlling the budget and transformations of nitrogen in the ocean. Nitrogen is a critical nutrient limiting marine production, and the balance of its redox cycling controls how much nitrogen is added or removed from the ocean by redox-sensitive processes.

    ROADMAP OBJECTIVES: 1.1 4.1 4.2 5.1 7.1
  • Dynamical Evolution of Multiple Star Systems

    During the past year I have performed 200,000 numerical simulations of newborn triple systems embedded in their placental gas cores. This has led to a number of surprising results, primarily a new model for the formation of extremely wide binaries, which is now in press in Nature.

  • Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements

    Abundances of both common and trace elements can have substantial effects on the habitability of stellar systems. We study the formation and composition of structures in supernova explosions that deliver bioessential elements to material that will form new stars and planets. We use the abundance of the element europium to estimate the abundances of uranium and thorium in nearby stellar systems and their effects on the thermal evolution of extrasolar planets. The relative abundances of common elements vary substantially among nearby stars, and we find that the impact of this on a star’s evolution can change the amount of time its planets are habitable by billions of years.

  • Astrophysical Controls on the Elements of Life, Task 7: Update Catalog of Elemental Ratios in Nearby Stars

    We have created the first complete database of bioessential elements for the stars closest to the Sun, including those hosting exoplanets.

  • Establishing the Source of Earth’s Water

    Understanding the sources and delivery mechanisms of water to the Earth and the other terrestrial planets allows for the validation of planetary accretion models. This information can help us establish at what time the Earth contained sufficient water for the development of life. A key parameter in determining the source(s) of terrestrial planetary water is the hydrogen isotope composition of this water. However, hydrogen fractionation during surface and atmospheric processes on Earth changes the Deuterium/Hydrogen (D/H) ratio in the various water reservoirs. Therefore, to determine the primordial D/H ratio of Earth’s water we must find a reservoir that has been unaffected by these processes. Plate tectonics is known to drag surface water down into the crust and the upper mantle, but the transition zone and lower mantle are thought to be uncontaminated by surface water. The aim of this project is to sample hydrous minerals and melt inclusions sourced from these uncontaminated regions. We will then analyze these samples using the Cameca ims 1280 ion-microprobe at the University of Hawaii to produce a dataset that establishes the Earth’s primordial D/H ratio.

  • Forces Important for Astrobiology: Collisions and Sublimation in the Main Belt

    In the Asteroid Belt, we sometimes observe different varieties of sudden, transient activity. One of these varieties of activity, sublimation tails associated with Main Belt Comets (MBCs), indicates the presence of a new reservoir of water inside the habitable zone, and is a major research subject of UHNAI. Other forms of activity, like collisions, can mimic MBCs. We have been working to develop computational models to distinguish between collisions and comet-like sublimation. In the course of this work, we have performed the first known numerical fit of a past Solar System impact event, demonstrating, from a months old debris trail, that the “comet” P/2010 A2 is really an impact, and constraining the impactor’s direction.

  • Stellar Radiative Effects on Planetary Habitability

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We looked at how the Sun’s brightness would have changed with time providing wavelength-dependent scaling factors for solar flux anywhere in the solar system from 0.6 to 6.7Gyr. Extrasolar planetary systems can only be determined through studying the host star; therefore we have also worked on determining the ages of Kepler planet host stars. We have constructed far ultraviolet to mid-infrared stellar spectra for 44 stars for being used as input in climate and photochemical models that are applied for determining habitable zones and possible characteristics of habitable planets. We have looked into the effect of methane (CH4) and hydrogen (H2) on the outer edge of the habitable zone for F, G, and M stars. We have studied the effect of host star stellar energy distribution (SED) and ice-albedo feedback on the climate of extrasolar planets.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 7.2
  • Evolution of Protoplanetary Disks

    Drs. Aki Roberge and Carol Grady are pursuing studies related to Theme 2 of the NASA GSFC Astrobiology Node, “From Molecular Cores to Planets: Our Interstellar Heritage.” Over the last year, they have continued work on two Open Time Key Projects for the Herschel Space Observatory, an ESA mission launched in May 2009. Herschel is spearheading the next big advances in our knowledge of planet formation, protoplanetary disk evolution, and debris disks. One project (GASPS) is illuminating the evolution of gas abundances and chemistry in protoplanetary disks over the planet-forming phase. The other (DUNES) has sensitively probed the Sun’s nearest neighbors for signs of cold debris disks associated with extrasolar Kuiper Belts.

  • Habitability of Extrasolar Planets

    We model if and under what conditions some of the recently detected Super-Earths – small, Earth-sized planets that have been discovered in in the classical Habitable Zone Sun-like stars – could be habitable. These models explore the underlying physics of planetary atmospheres and their remotely detectable features.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 6.2 7.2
  • Fingerprinting Late Additions to the Earth and Moon via the Study of Highly Siderophile Elements in Lunar Impact Melt Rocks

    We have completed analysis of highly siderophile elements and Os isotopes in seven Apollo 17 impact melt breccias. The resulting large database for impact melt rocks from this site is consistent with a dominant signature imparted to rocks from this site by a single major impactor, most likely the Serenitatis impactor. The composition of this impactor was broadly chondritic, but characteristically enriched in Re, Ru and Pd relative to most chondrites. Studies of diogenites and angrites show that late accretion to small bodies occurred very early in solar system history.

  • Herschel Lunar Impact Study

    The Herschel Space Telescope, parked in a Lagrangian point beyond the Moon, will be retired in 2013. A controlled, high velocity impact by the Herschel spacecraft into the lunar surface would provide new data about the Moon and elucidate the nature of lunar volatiles, including water ice. The impact site should be at a cold, shadowed location, but the impact plume needs to be sunlit and observable from Earth, which places significant constraints on possible impact locations. We have carried out calculations of shadow heights to identify potential impact sites that simultaneously satisfy all necessary constraints.

  • Habitability of Water-Rich Environments, Task 2: Model the Dynamics of Icy Mantles

    One of Jupiter’s moons, Europa, is one of the few places in the solar system in which the physical and chemical conditions may be suitable for sustaining life. Europa is composed on an outer H2O layer, comprised of rigid ice overlying a liquid water ocean. It is this liquid water ocean which has been hypothesized as having the ingredients necessary for life, but it is shielded from our observation by the thick ice layer. However, under certain conditions, the ice layer is expected to undergo convection, possibly transporting chemicals from the liquid ocean to the surface, where we may be able to detect them. We perform computer modeling of ice/ocean convection to investigate how ocean material is carried up through the ice layer and whether it is expected to reach Europa’s surface. This work provides guidance for future missions which may probe the chemistry of the ice surface.

  • Ice Chemistry of the Solar System

    We are currently in the process of establishing a research program at the University of Hawai’i at Manoa to investigate the evolution of Solar System and interstellar ices; these grains are chemically processed continuously by radiation from either our Sun, or galactic cosmic radiation (GCR). The nature of the chemistry that occurs here is an important component of understanding the origin of complex biomolecules that could have seeded the primordial Earth, helping to kick-start the origin of life. We have constructed one of the leading laboratory facilities in the world capable of carrying out this research, and we focus on establishing the underlying chemical pathways.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3 4.1 7.1 7.2
  • Fischer-Tropsch Type (FTT) Reactions in the Solar Nebula

    We have pursued this research topic on two fronts over the past year. First we have almost completed construction of the new 10-station FTT experimental system, financed by NASA’s Exobiology R&A Program. This system replicates our original experimental setup in a much more compact fashion and should allow us sufficient flexibility to carry out several very long-term, low-temperature experiments while simultaneously having the capability to do a number of much faster experiments at higher temperatures. The second research front we have pursued is in trying to predict the “global” consequences of potentially extensive FTT reactions on the chemistry of the solar nebula and on protostars in general. In addition to the potential for FTT processes to produce interesting pre-biotic organic molecules such as methyl cyanide, various amino acids and more complex aromatic compounds, or the possibility that the macromolecular organic coating produced via FTT reactions could trap noble gases and carry these materials into planetary bodies, we believe that FTT reactions could have several additional, broader consequences for nebular chemistry – and even possibly for the chemical evolution of the galaxy.

  • Habitability of Water-Rich Environments, Task 3: Evaluate the Habitability of Europa’s Subsurface Ocean

    Europa is of keen interest to astrobiology and planetary geology due to its indications of a sub-surface ocean. Understanding of Europa’s oceanic composition and pH is important to evaluate habitability of the icy moon. Knowledge of the global distribution and timing of Europan geologic units is a key step for understanding the history of the satellite and for identifying areas of recent activity. We are evaluating the habitability of a subsurface ocean of Europa through evaluation of chemical composition and salinity of oceanic water. We use numerical approaches to model interaction of possible rocks on Europa with water formed through melting of ices. In addition, we use chemical and mineralogical signs of water-rock interactions in carbonaceous chondrites as a proxy for aqueous processes on Europa.

  • NIR Spectroscopic Observations of Circumstellar Disks Around Young Stars

    As a research scientist in the Planetary Systems Laboratory at NASA GSFC, A. Mandell studies the formation and evolution of planetary systems and the structure and composition of the atmospheres of extra-solar planets utilizing near-infrared spectroscopy. Mandell’s current observing campaigns focus primarily on ground-based and space-based spectroscopy of circumstellar disks and extrasolar planetary transits and secondary eclipses using instruments on the Hubble Space Telescope, the Keck telescope and the Very Large Telescope. Additionally, Mandell assists as a co-investigator on computational studies of terrestrial planet formation and evolution using N-body simulations of planetary accretion.

  • Understanding Past Earth Environments

    For much of the history Earth, life on the planet existed in an environment very different than that of modern-day Earth. Thus, the ancient Earth represents a planet with a biosphere that is both dramatically different than the one in which we live, but that is also accessible to detailed study. As such, it serves as a model for what types of biospheres we may find on other planets. A particular focus of our work was on the “Early Earth” (formation through to about 500 million years ago), a timeframe poorly represented in the geological and fossil records but comprises the majority of Earth’s history. We have studied the composition and pressure of the ancient atmosphere; modeled the effects of clouds on such a planet; studied the sulfur, oxygen and nitrogen cycles; and explored atmospheric formation of molecules that were likely important to the origins of life on Earth.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 5.1 5.2 6.1
  • Main Belt Comets and Water in the Outer Asteroid Belt

    The ongoing discovery of potential members of a new class of objects, known as Main Belt Comets (MBCs), raises a number of questions regarding their structure, composition, and origin. These may indicate that the entire outer asteroid belt contains significant volatile material, and this has impli-cations for its delivery to the terrestrial planets. Whatever the origin is, they have spent most of their lifetimes in the asteroid main belt, which has been considered too hot for ice to survive for any length of time. The low conductivity of porous cometary material suggests, however, that ice may be retained in the interior of main belt bodies, despite continual solar heating. Indeed, analytical estimates, as well as numerical computations, indicate that this is possible. We investigate the ice survival question by means of detailed numerical modeling of long-term evolution for a range of ini-tial parameters. As another step in this study, we try to characterize the impact-triggering mecha-nism that supports the observed activity, however diffuse and weak it may be. This is achieved by means of statistical estimates of how a population of very small colliding bodies will ablate the sur-face and affect the way heat is conducted into any deeper buried water ice pockets. The main ques-tions that we address are: (a) To what extent and under what conditions (related to structure and composition) may water ice be preserved in MBCs for the age of the Solar System; (b) How deep below the surface is the ice expected to be found? (c) What is the rate at which small impacts ex-pose fresh water ice pockets and cause it to sublimate?

  • Understanding the Early Mars Environment

    There is no liquid water on modern Mars, although there is plenty of solid ice. Observations from orbiting satellites and rovers on the ground suggest that liquid water may have flowed over the Martian surface in the distant past. VPL researchers are studying the geologic record of Mars for clues of past water, and investigating climate and chemical conditions under which water would be stable. Team members examined different climate feedbacks and geochemical processes that could have warmed the early Mars. Some members are also active members of the MSL science team.

  • Measuring Interdisciplinarity Within Astrobiology Research

    To integrate the work of the diverse scientists working on astrobiology, we have harvested and analyzed thousands of astrobiology documents to reveal areas of potential connection. This framework allows us to identify crossover documents that guide scientists quickly across vast interdisciplinary libraries, suggest productive interdisciplinary collaborations, and provide a metric of interdisciplinary science.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Progress Report From G. Blake – CIT

    The Blake group has been carrying out joint observational and laboratory program with NAI node scientists on the water and simple organic chemistry in the protoplanetary disk analogs of the solar nebula and in comets. Scientific results continue to flow at a rapid clip. We have followed up our major overview papers outlining the results from our extensive (>100 disks) Spitzer IRS survey of the molecular emission from the terrestrial planet forming region with follow-up work with GSFC scientists on the high spectral resolution ground-based observations of such emission and that from cometary comae (and possible non-transiting exoplanets) using the Keck telescope and the VLT. We have measured the angular scale of the disk emission, and discovered a new transitional disk class characterized by a wide angle molecular wind. We have probed the outer disk’s water emission with the Herschel HIFI instrument, and also measured the (D/H)water ratio in a Jupiter Family Comet for the first time with Herschel – finding a value consistent with that in the Earth’s oceans. Our first Cycle 0 ALMA data are now in hand, and beautifully demonstrate the high angular resolution observations of simple organics in the outer regions of disks and comets that will become possible over the coming years. The full suite of results will permit the first detailed examination of the radial water and gas phase organic chemistry in planet-forming environments.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 7.2
  • VPL Databases, Model Interfaces and the Community Tool

    The Virtual Planetary Laboratory (VPL) develops computer models of planetary environments, including planets orbiting other stars (exoplanets) and provides a collaborative framework for scientists from many disciplines to coordinate their research. As part of this framework, VPL develops easier to use interfaces to its models, and provides model output datasets, so that they can be used by more researchers. We also collect and serve to the community the scientific data required as input to the models. These input data include spectra of stars, data files that tell us how atmospheric gases interact with incoming stellar radiation, and plant photosynthetic pigments. We also develop tools that allow users to search and manipulate the scientific input data. This year we provided Earth model datasets, new tools for searching the molecular spectroscopic database, and a new database of biological pigments. All of these products and others are published on the VPL Team Website at:

    ROADMAP OBJECTIVES: 1.1 1.2 3.2 4.1 6.1 7.1 7.2
  • Remote Sensing of Organic Volatiles in Planetary and Cometary Atmospheres

    In the last year, we have greatly advanced our capabilities to model spectra of cometary and planetary atmospheres (Villanueva et al. 2012a, 2012b). Using these newly developed analytical methods, we derived the most comprehensive search for biomarkers on Mars (Villanueva et al. 2012, submitted) from our extensive database of high-quality Mars spectra. Furthermore, we retrieved molecular abundances of several comets (Villanueva et al. 2012c, Gibb et al. 2012, Paganini et al. 2012a/b), and of several young circumstellar disks (Mandell et al. 2012). These great advancements have allowed us to understand the infrared spectrum of planetary bodies and their composition with unprecedented precision.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 7.1 7.2
  • The Chemical Composition of Comets

    Understanding the origin and the distribution of organic matter and volatile material in the early Solar System is of central importance to astrobiology. Comets, which have escaped the high-temperature melting and differentiation that asteroids experience, are “astrobiological time cap-sules” that have preserved a valuable record of the complex chemical and physical environment in the early solar nebula. Studying the primordial chemistry and evolution of cometary nuclei will pro-vide important clues about the birthplace of comets and in turn place strong constraints on the cur-rent Solar System formation models. In late 2011 and 2012, two bright comets, C/2011 L4 (Pan-STARRS) and C/2009 P1 (Garradd), visited the inner Solar System for the first time. In March 2012, C/2011 L4 (PanSTARRS) is expected to appear even brighter than the comet Hale-Bopp, the bright-est since 1996. We have recently studied C/2011 L4 and C/2009 P1 in the sub-millimeter and infra-red wavelength regimes using the James Clerk Maxwell Telescope (JCMT), Caltech Submillimeter Observatory (CSO), Gemini-North and the Keck Telescopes on Mauna Kea, Hawaii. We investigated the chemical compositions of these comets and compared them with those of other comets. Our unique observations of these two bright comets over a wide range of heliocentric distances allow monitoring of the abundances of several native molecules that are key to understanding comet formation.

    We are also conducting a systematic survey of comet brightness around their orbits in order to model their volatile composition. Using space-based data from the Akari Satellite, the WISE Satel-lite, and the EPOXI mission we are showing that these models can provide information on gas spe-cies normally not detectable through Earth’s atmosphere. This gives us the opportunity to investi-gate the wide spread distribution of key cometary volatiles (water, carbon monoxide and carbon dioxide) and their relation to protoplanetary disk chemistry.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • The Neoproterozoic Carbon Cycle

    We are studying the dynamics of the rise of oxygen during the Neoproterozoic (1 billion years ago to 543 million years ago) through culturing experiments, models and observations (see the progress report on the Unicellular Protists). We are testing the predictions of the following “anti-priming” hypothesis: if more easily degradable organic matter was degraded in oxic environments, this may have slowed down the degradation of organic matter in anaerobic environments and the overall degradation of organic matter, increasing the concentration of oxygen in the atmosphere and the surface ocean. We are currently developing theoretical predictions and testing these ideas by laboratory enrichment cultures of anaerobic microbes that degrade complex substrates in the presence and absence of labile organic compounds.

    ROADMAP OBJECTIVES: 1.1 4.1 4.2 5.2 6.1 6.2
  • Rings in Debris Disks: A Signature of Planets or of Volatiles?

    Marc Kuchner and his collaborator Wladimir Lyra at JPL have developed a new explanation for the origin of eccentric rings in debris disks—like the rings around Fomalhaut and HR 4796. A popular explanation for these rings is that they represent dust shepherded by extrasolar planets, which are often too faint to see. Instead of hidden planets, Kuchner and Lyra’s models invoke a hidden component of gas in these disks, which supports a thermal instability that causes the dust to clump together in narrow eccentric rings. The presence of this instability makes inferring the presence of exoplanets more difficult, but it may aid in planet formation and provide important clues to the history of volatiles in the solar system.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1
  • Water in Planetary Interiors

    The mineral MgSiO3 in the perovskite structure is thought to be the most abundant solid mineral phase in the Earth composing up to 45% of the mass of the planet. Because Earth’s oceans constitute only 0.023% of the planet’s mass, even small amounts of H substitution in the perovskite phase can control the H balance of a planet the size of Earth or Venus. There is considerable disagreement among previous workers about H solubility in the perovskite phase. We have synthesized samples of high-pressure mineral phases that are likely hosts for hydrogen, and thus water, in planetary interiors, and measured physical properties including crystal structure, density, elasticity, and electrical conductivity to see if there is evidence of deep hydration in the Earth.

  • Summary of Research Accomplishments for L. Paganini

    Dr. Lucas Paganini has performed astronomical observations of six comets that led to four publications in peer-reviewed journals (namely, two papers as first author and two as co-author). In July 2011 he (and colleagues) discovered that comet C/2009 P1 (Garradd) is CO-rich. And in 2012 he (and colleagues) detected carbon monoxide in a comet beyond Jupiter (at 6.26 AU from the Sun), thus setting a new record for detections by infrared (IR) spectroscopy of parent volatiles in comets at relatively large heliocentric distances. Until now considered to be a somewhat impossible task with IR ground-based facilities, these discoveries open up new opportunities for targeting multiple volatile species at low rotational temperatures, as well as the unique possibility to characterize hypervolatiles in distant comets.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Water in the Moon

    The discovery in 2008 that the Moon contains at least some water has important implications for the origin of the Earth-Moon system and planetary accretion in general, the source of water for the Earth, and the processes involved in lunar differentiation. We have concentrated our studies on a class of lunar samples that ought to contain the most H2O, so-called KREEP rocks (rich in potassium, rare earth elements, phosphorous, and other elements with similar geochemical behavior, including H2O). We find that these rocks contain considerably less H2O than do mare basalt and pyroclastic deposits measured by others, possibly suggesting that the Moon contained little water during its initial differentiation, implying a post-accretion addition.