2011 Annual Science Report

Astrobiology Roadmap Objective 1.1 Reports Reporting  |  SEP 2010 – AUG 2011

Project Reports

  • Cosmic Distribution of Chemical Complexity

    The central theme of this project is to explore the possible connections between chemistry in space and the origins of life. We start by tracking the formation and development of chemical complexity in space from simple molecules such as formaldehyde to complex species including amino and nucleic acids. The work focuses on molecular 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 in 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
  • 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 aims 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.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Astrophysical Controls on the Elements of Life, Task 1: High-Precision Isotopic Studies of Meteorites

    The elemental abundances of planetary systems potentially are affected by contributions from nearby supernovae. Injection of supernova material can be studied by isotopic analyses of meteorites, especially calcium-rich, aluminum-rich inclusions (CAIs) within them, which reveal the presence in the forming Solar System of short-lived radionuclides. Initial abundances of these radionuclides not only signal contributions from a supernova but also provide a chronometer to date the injection and other formation events. Radionuclides, especially 26Al, also can affect the thermal evolution and volatile retention within planetary bodies. In this task we seek to measure initial abundances of radionuclides in meteorites, especially CAIs, and to constrain the timing of early Solar System events.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Project 1: Looking Outward: Studies of the Physical and Chemical Evolution of Planetary Systems

    This project five main objectives focused broadly on understand the origin and early evolution of our solar system. First, we have employed a new planet finding spectrometer to aid in detecting planetary systems surrounding neighboring stars. Second, we have begun the Carnegie Astrometric Planet Search project to detect giant planets around nearby loss mass dwarf stars. Third, we focused on understanding of radial transport and mixing of matter in protoplanetary disks. Fourth, we have continued to survey of small planetary size objects in the Kuiper belt. Fifth, we have continued our studies of the composition, structure, and ages of circumstellar disks.

    ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1
  • Task 1.1.1 Models of the Internal Dynamics: Formation of Liquids in the Subsurface and Relationships With Cryovolcanism

    The internal and external geologic evolution of Titan was investigated so as to constrain the environment in which organic evolution has proceeded over time.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3
  • Astrobiological Exploration of Mars

    The Mars Science Laboratory (MSL) mission, due for launch in November 25th, 2011, has four primary science objectives for looking at habitable environments: assess the biological potential of at least one target environment by determining the nature and inventory of organic carbon compounds; characterize the geology of the landing region at all appropriate spatial scales by investigating the chemical, isotopic, and mineralogical composition of the surface and near-surface materials; investigate planetary processes of relevance to past habitability, including the role of water and carbon dioxide; and characterize the broad spectrum of surface radiation. Project scientist John Grotzinger and other MIT NAI team members have been contributing to numerous aspects of site selection, site evaluation and the optimal Mars environments for biosignature formation and preservation.

    ROADMAP OBJECTIVES: 1.1 2.1
  • AIRFrame Technical Infrastructure and Visualization Software Evaluation

    We have analyzed over four thousand astrobiology articles from the scientific press, published over ten years to search for clues about their underlying connections. This information can be used to build tools and technologies that guide scientists quickly across vast, interdisciplinary libraries towards the diverse works of most relevance to them.

    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
  • 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 5.3 6.1 6.2 7.1 7.2
  • Astrophysical Controls on the Elements of Life, Task 2: Model the Chemical and Dynamical Evolution of Massive Stars

    The elemental ratios in stars and their planets will differ because each star has a different contributions from sources of stellar nucleosynthesis. The dominant contributions of heavy elements to molecular clouds come from supernova explosions, which may also contribute material just prior to star formation. To quantify what elements might be contributed by supernovae, in this task we first perform numerical simulations of stellar evolution, predicting how stellar properties (e.g., luminosity, temperature, internal composition, stellar winds, etc.) change over time. These results are made available to the public. We then simulate the explosions of massive stars as supernovae, to determine what elements are ejected. As a complementary study, we are also using spectra of stars, obtained during radial velocity planet searches, to find the chemical abundances of hundreds of nearby, potentially habitable stars, to assess the variability of starting compositions, and we are also modeling how the habitable zones of stars with these starting compositions might vary over time.

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

    This project uses computer models and laboratory work to better understand how volatile materials that are important for life, like water, methane, and other organic molecules, are delivered to terrestrial planets. Habitable planets are too small to gravitationally trap these volatiles directly from the gas disk from which they formed, and instead they must be delivered as solids or ices at the time of the planet’s formation, or ongoing as the planet evolves. These trapped volatiles are eventually released to form our oceans and atmosphere. In this task we use computer models of planet formation and migration to understand how the asteroid belt, which is believed to be the source of the Earth’s oceans, was formed. We also use models to understand what happens to meteoritic material as it enters a planet’s atmosphere, especially where it gets deposited in the atmosphere, what happens to it chemically, and how it interacts with the light from the parent star. .

    ROADMAP OBJECTIVES: 1.1 3.1 4.1 4.3
  • Disks and the Origins of Planetary Systems

    This task is concerned with understanding the evolution of complex habitable environments as primitive planetary bodies are forming in a developing protoplanetary disk. The planet formation process begins with the collapse 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 hydrocarbons and mixed in the dust and gas envelope within the disk. Gravitational attraction among the myriad small bodies leads to planet formation. If the newly formed planet is a suitable distance from its star to support liquid water at the surface, it is in the so called “habitable zone.” 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
  • Task 1.1.2 Models of the Reaction Between Hydrocarbons and Water Ice

    Reactions between hydrocarbons and water ice was modeled to assess the possible extent of prebiotic compound formation in this context. Various environments where organics and liquids could be in contact were considered.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3
  • 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
  • Project 3: The Origin, Evolution, and Volatile Inventories of Terrestrial Planets

    This research project brings together a large team of scientists with a unified goal understanding the origin and evolution of volatiles (C, H, O, and N) in planetary interiors. It includes a theoretical study of planet formation with focus of addressing the abundance of volatiles in objects that ultimately combine to form the terrestrial planets. The project gains from information being currently revealed through the NASA Messenger mission in orbit around Mercury. The project has an experimental component that focuses on studying volatiles deep in planetary interiors using ultra-high pressure devices and molecular spectroscopy for species interrogation. Finally, it includes a systematic study of the chemistry of mineral inclusions in diamonds, where diamond serves to trap minerals in a natural high pressure container. These studies allow CIW NAI scientists probe the chemistry of Earth’s deep mantle and help reveal how Earth’s plate tectonics may have started.

    ROADMAP OBJECTIVES: 1.1 3.1 4.1
  • Task 1.2 Interaction of Methane/ethane With Water Ice

    Laboratory work led to several results. Tholins are entrained in the subsurface during a methane rain. As the liquid evaporates, the tholins remain trapped in the subsurface. The JPL Titan chamber (Figure 1) also was used to test a rain drop sensor developed by a group of students at University of Idaho that could be embarked on future missions to Titan.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • 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 completed and published our work on the build up and detectability of sulfur-based biosignatures in early Earth-like atmospheres, especially for planets orbiting stars cooler than our Sun. We also continued to explore the potential 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 3: Model the Injection of Supernova Material Into Star-Forming Molecular Clouds

    Our Solar System is known to have contained short-lived radionuclides such as 26Al and 60Fe when it formed. These must have been created either during or just before Solar System formation. A supernova explosion is thought to be the most likely source. Depending on the manner of supernova injection, other elements relevant to life may accompany the radionuclides. In this task we study how a supernova might inject material into the molecular cloud from which the Solar System formed, before formation of the protostar. This tests the hypothesis of supernova injection and quantifies its contributions to radionuclides and other elements.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Path to Flight

    Our technology investigation, Path to Flight for astrobiology, utilizes instrumentation built with non-NAI funding to carry out three science investigations namely habitability, survivability and detectability of life. The search for life requires instruments and techniques that can detect biosignatures from orbit and in-situ under harsh conditions. Advancing this capacity is the focus of our Technology Investigation.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 7.1 7.2
  • Analogue Environment Deployments on the Big Island

    We are using the saddle region on the Big Island of Hawaii, in collaboration with NASA teams and the Canadian Space Agency in order to test technology related to sustainable living on the moon. My group will evaluate the utility of 3-D visualization in robotic navigation, in particular for the ex-ploration of lava tubes.

    ROADMAP OBJECTIVES: 1.1 2.1 4.1 4.3 6.1 6.2 7.1
  • Biosignatures in Ancient Rocks

    The Earth’s Archean and Proterozoic eons offer the best opportunity for investigating a microbial world, such as might be found elsewhere in the cosmos. The ancient record on Earth provides an opportunity to see what geochemical signatures are produced by microbial life and how these signatures are preserved over geologic time. As part of our integrated plan, we will study geochemical, isotopic, and sedimentary signatures of life in order to understand the context in which these biosignatures formed.

    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 3: Pathways for Exogenous Organic Matter to the Early Earth and Mars

    This project focuses on investigating the asteroidal contribution of organic molecules to the terrestrial planets in the early Solar System – molecules that may have contributed to the rise of life on Earth and potentially on Mars. Some types of meteorites contain significant amounts of organic compounds, including amino acids. These compounds are presumed to have formed by non-biological processes, either in the solar nebula (with subsequent incorporation into asteroids during their formation), or within the asteroids themselves by liquid water acting on the original minerals. Fragments from asteroids arrive at the Earth (and Mars) at comparably low velocities and can efficiently deliver intact organic molecules to the surfaces of these planets.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Astrophysical Controls on the Elements of Life, Task 4: Model the Injection of Supernova Material Into Protoplanetary Disks

    Our Solar System is known to have contained short-lived radionuclides such as 26Al and 60Fe when it formed. These must have been created either during or just before Solar System formation. A supernova explosion is thought to be the most likely source. Depending on the manner of supernova injection, other elements relevant to life may accompany the radionuclides. In this task we study how a supernova might inject material into the protoplanetary disk from which the planets in the Solar System formed, after the formation of the protostar. This tests the hypothesis of supernova injection and quantifies its contributions to radionuclides and other elements.

    ROADMAP OBJECTIVES: 1.1 3.1
  • 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 the star 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 the finding that tidal effects could be strong enough to cause a planet to overheat and ultimately lose its ocean, that large changes in the direction of the spin-axis of a planet could potentially increase the range of distances from the star in which the planet could remain habitable, and that the Sun may have moved significant distances outward through the Galaxy during its lifetime, changing the rate of at which large bodies have hit the Earth.

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

    The focus of this project is to explore indicators of life outside of Earth, both within the Solar System and on extrasolar planets. The work includes studies of the chemistry and composition of the Solar System, and the past history of conceivable sites for life in the Solar System. We also look for habitable planets outside the Solar System; work on developing new techniques to find and observe potentially habitable planets; and model the dynamics, evolution and current status of a variety of extrasolar planets.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 4.1 4.3 6.2 7.1 7.2
  • Task 2.1.1 Master Atmospheric Chemistry Simulation

    The development of a master atmospheric model is nearing completion. Based on an older Titan model, the current model has been updated this year to include a treatment of chemical equilibrium, a description of aerosols, and a numerical model for condensation on and sublimation of atmospheric organic molecules from aerosol particles. To allow a global simulation of Titan atmospheric organic chemistry, the computer model is being recoded to support parallel processing.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Project 1D: Evolution of Life Related to the Development of the Earth’s Core

    We investigated the effect of evolution of the Earth’s core on the magnetic field, which bears on the extent of magnetic shielding of cosmic radiation, which in turn has implications for the evolution of life. We hypothesize that extensive magnetic shielding likely occurred only after turbulent flow in the liquid outer core subsided, which would have occurred after 1 or 2 b.y. of inner core solidification, allowing differential rotation of the inner and outer core. These results suggest that life which evolved in the first 1 to 2 b.y. of Earth history would have had to develop strategies to cope with high cosmic radiation. The most effective strategy is to use shielding by absorption of radiation by water. Consequently evolution of life on the surface of the Earth occurred much later in the Earth’s history.

    ROADMAP OBJECTIVES: 1.1 4.1
  • Collisional Evolution of Planetesimal Systems and Debris Disk Patterns

    Marc Kuchner and his graduate student Erika Nesvold are working on a new tool for modeling the collisional evolution and 3-D distribution of planetesimals in planetary systems and debris disks. We plan to use this tool for interpreting images of planetary systems: modeling images and other data on circumstellar disks. We expect to be able to use this approach to locate hidden exoplanets via their dynamical influence on the shapes of the disks. We also expect to use our new models to understand the evolution of planetesimals in the solar system during the time when these planetesimals probably delivered the Earth’s ocean water.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1
  • 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 these minerals play in the development of potential life forms. One hydrous mineral found on Earth and inferred from in situ measurements on Mars, is the mineral Jarosite, KFe3(SO4)2(OH)6. We are investigating whether radiometric ages, specifically 40Ar/39Ar ages on jarosite can be interpreted to accurately record climate change events on Mars. This project not only requires understanding the conditions required for jarosite formation and preservation on planetary surfaces, but also assessing under what conditions its “radiometric clock” can be reset (e.g., during changes in environmental conditions such as temperature). By studying jarosites formed by a variety of processes on Earth, we will be prepared to analyze and properly interpret ages measured from jarosite obtained from future Mars sample return missions.

    ROADMAP OBJECTIVES: 1.1 2.1 7.1
  • Task 2.1.2.1 Atmospheric State and Dynamics

    The chemical model requires a description of the background state of the atmosphere, specifically temperature and circulation as a function of latitude and longitude.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Astrophysical Controls on the Elements of Life, Task 5: Model the Variability of Elemental Ratios Within Clusters

    In Tasks 3 and 4 we study how supernovae may enrich indvidual solar systems at the peripheries of high-mass star-forming regions. In this task we study in a statistical sense how stars of a variety of masses at the ends of their lives enrich star-forming molecular clouds and stellar clusters. Through detailed numerical hydrodynamic simulations we are studying the mixing of heavy elements into the surrounding medium and comparing our predictions to variable abundance ratios in present-day clusters. We also apply this research to star formation in the early universe, studying the transition between pristine (very low metallicity) and enriched star formation.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Composition of Parent Volatiles in Comets: Oxidized Carbon

    GCA Co-Investigator Dr. Michael DiSanti continued his work on measuring parent volatiles in comets using high-resolution near-infrared spectroscopy at world class observatories in Hawai’i and Chile. The goal of this work is to build a taxonomy of comets based on ice compositions, which show considerable variation among comets measured to date. DiSanti’s research emphasizes the chemistry of volatile oxidized carbon, in particular the efficiency of converting CO to H2CO and CH3OH on the surfaces of icy interstellar grains, through H-atom addition reactions prior to their incorporation into comets. The work requires planning and conducting observations, processing of spectra, and development and application of fluorescence models for interpretation of observed line intensities. Major strides in these areas were realized during this period of performance.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Astrophysical Controls on the Elements of Life, Task 6: Determine Which Elemental or Isotopic Ratios Correlate With Key Elements

    In this task we explore how key elements and radioactive isotopes are created by nucleosynthesis during the explosions of massive stars. We also study the formation and composition of structures in supernova explosions that may be relevant to delivery of bioessential elements to forming solar systems. In particular, we have investigated how the bioessential elements Ca and Fe are produced during supernovae. We have discovered that they are produced by 6 distinct nucleosynthetic pathways, and that their relative abundances can be probed by observations of the gamma-ray radiation from the radioactive decay of the isotopes 44Ti and 56Ni into 44Ca and 56Fe. We also have investigated the co-production of O isotopic anomalies with the short-lived radionuclide 26Al. We find that delivery of 26Al to the early solar system would not necessarily have altered significantly its O isotopic composition.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Task 2.1.2.2 Atmospheric Observations

    A previously unsuspected seasonal change in the altitude of Titan’s detached haze layer was discovered and used to test current models of the formation of the haze and related dynamical and microphysical processes.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Cosmochemical Search for the Origin of Water in Planetary Bodies

    The ultimate goal of our study is to understand the origin of water in planetary bodies (asteroids, comets and terrestrial planets). In particular we want to understand better the water-based chemis-try that happens on these bodies. This gives important insights into the role(s) played by water dur-ing the origin of our Solar System. We are taking a new approach to understanding aqueous altera-tion processes in carbonaceous chondrites by investigating the distribution and composition of or-ganic compounds in aqueously altered chondrites. This research will also shed light on the nature of organic compounds in asteroids and in planetesimals that might have delivered organic compounds to the early Earth. This research will use a variety of micro-analytical techniques (optical microscopes, scanning electron microscope, electron microprobe, transmission electron microscope, ion microprobe, Raman spectroscopy) to investigate the aqueous alteration that has affected the CR chondrites. These meteorites were chosen because they exhibit a complete series of alteration, from very lightly altered to completely altered, and they have experience almost no thermal metamorphism.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2
  • 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
  • Modelling Planetary Albedo & Biomarkers in Rocky Planets’/moons Spectra

    Using data from Kepler and new ground-based detections, Lisa Kaltenegger and Dimitar Sasselov have identified which confirmed and candidate planets orbit within the Habitable Zone and could provide environments for basic and complex life to develop. They have also developed atmosphere models for extrasolar planetary environments for different geological cycles and varied environments for the advent of complex life. The team modeled detectable spectral features that identify such planetary environments for future NASA missions like the James Webb Space Telescope.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 6.2 7.2
  • Task 2.2.1 Characterization of Aerosol Nucleation and Growth

    A quantitative understanding of the particle formation and growth in the Titan atmosphere is still unrealized. Laboratory work is being conducted to clarify these processes.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Astrophysical Controls on the Elements of Life, Task 7: Update Catalog of Elemental Ratios in Nearby Stars

    Future surveys like Kepler for habitable planets will likely be limited to select regions of the sky. In anticipation, we have created the first maps of what the solar neighborhood looks like in the “light” of bio-essential elements such as C, N, O, Si and Fe. To make these maps, we painstakingly compiled and analyzed 25 years’ worth of measured data on 44 chemical elements in 1224 stars that are within 500 light-years of the Sun and potentially host habitable exoplanets. Our new catalog “the Hypatia Catalog“ and the first maps produced from it suggest there are certain directions on the night sky that show enhanced abundances of bio-essential elements. These “habitability hotspots” or “habitability windows” may be of use in current and future searches for Earth-like planets.

    ROADMAP OBJECTIVES: 1.1 7.2
  • 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
  • Formation and Prospect of the Detection of Habitable Super-Earths Around Low-Mass Stars

    In the quest for potentially habitable planets, the nearest stars are of special importance. These stars have accurate distances and precisely determined stellar parameters, and are the only stars for which follow-up by astrometry and direct imaging is possible. Within the Sun’s immediate neighborhood, M stars constitute the majority (72%) of nearby stars. The proximity, low surface temperatures, and small masses of these stars have made them unique targets for searching for terrestrial and habitable planets. During the past five years, team member N. Haghighipour has been actively involved in the detection of extrasolar planets around M stars both in theoretical and observational fronts.

    ROADMAP OBJECTIVES: 1.1 1.2
  • Task 2.2.2 Ultraviolet/infrared Spectroscopy and Photoprocessing of Ice Films

    Only near-ultraviolet light at long wavelengths can penetrate to the deep Titan atmosphere, not being absorbed by atmospheric gas-phase species. Large hydrocarbons can absorb at these longer wavelengths. Condensed onto atmospheric particles, such hydrocarbons can undergo photochemical reactions initiated by absorption of near-ultraviolet photons.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Evolution of Protoplanetary Disks

    Drs. Aki Roberge and Carol Grady have continued work on two Open Time Key Projects for the Herschel Space Observatory, a far-infrared ESA mission launched in May 2009. One project (GASPS) is illuminating the evolution of gas abundances and chemistry in protoplanetary disks over the planet-forming phase; Drs. Roberge and Grady were co-authors on two GASPS journal published articles this year. The other (DUNES) has sensitively probed the Sun’s nearest neighbors for signs of cold debris disks associated with extrasolar Kuiper Belts; Dr. Roberge was a co-author on two DUNES journal articles published this year. Dr. Roberge was also a science team member for a SOFIA instrument concept that was developed in 2011 and proposed to NASA. The instrument, called the High Resolution Mid-Infrared Spectrometer (HIRMES), has a primary science goal of chemical evolution studies in protoplanetary disks.

    ROADMAP OBJECTIVES: 1.1
  • Project 8: 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 the collaborative interaction among the NAI investigators

    ROADMAP OBJECTIVES: 1.1 3.1 4.1 4.3
  • Postdoctoral Fellow Report: Mark Claire

    I have studied how biology might have impacted Earth’s early atmosphere, and how the Sun’s light has changed with time. More specifically, I’ve modeled how enhanced release of biogenic sulfur gases in earlier periods of Earth history may have left clues in the geologic record, and compared these predictions to the data. Furthermore, I have made a model of what how the light from the Sun would appear at any planet or any time in the solar system.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 7.2
  • Habitability of Water-Rich Environments, Task 2: Model the Dynamics of Icy Mantles

    Jupiter’s moon Europa provides a combination of physical and chemical conditions that may be among the most suitable in the solar system for sustaining life. Europa almost certainly has a liquid ocean. This ocean may have the ingredients necessary for life, but it is shielded from observation by a thick overlying ice layer. Under certain conditions this ice layer may undergo convection that can transport chemical species from the ocean to the surface, where they may be detected. Our computer modeling of convection in this ice layer aims to quantify how much ocean material may be brought to the surface. This work provides guidance for future missions to Europa.

    ROADMAP OBJECTIVES: 1.1 2.2
  • Task 3.1.1 Reactions of Organics With Ices and Mineral Grains

    A goal is to determine the potential role of mineral surfaces (i.e. meteorite fragments) in catalyzing reactions on Titan’s surface. There is also the possibility of low-energy electron and visible/UV photon stimulated chemistry on aggregates and organic aerosol surfaces.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Galactic Habitable Zone

    Life for certain exists in the Milky Way galaxy, however, understanding if there are certain regions in the galaxy that are more favorable to life is one of the thrusts of astrobiology. This project GHZ is described in terms of the spatial and temporal dimensions of the Galaxy that may favor the devel-opment of complex life. Of particular particular interest to astrobiologists, and to the general public, is whether or not our position in the Galaxy is favourable for the development of complex life.

    ROADMAP OBJECTIVES: 1.1 4.3
  • Habitability of Water-Rich Environments, Task 3: Evaluate the Habitability of Europa’s Subsurface Ocean

    Europa is of keen interest to astrobiologists and planetary geologists because of indications that it may possess a sub-surface ocean. In this task we seek to understand the global distribution and timing of Europan geologic units, to identify regions of recent activity. We also seek to map chemical signatures on its surface. Simultaneously we are numerically modeling the convection in the icy shell overlying the subsurface ocean, with a particular aim of determining whether chemical species from the ocean can be brought to the surface. Through this combined approach we seek to understand Europa’s ocean’s pH and composition, and evaluate the habitability of this icy moon.

    ROADMAP OBJECTIVES: 1.1 2.2
  • 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. We used models to study the effect of one very big flare on a planet with a carbon dioxide dominated atmosphere, like the early Earth’s, and found that these types of planets are well protected from the UV flux from the flaring star. We have also looked at the first quarter of Kepler data to study flare activity on “ordinary” cool stars, that have not been preselected for their tendency to have large flares. We find that these cool stars fall into two categories: stars that have long duration flares of several hours, but flare less frequently overall, and stars that have short duration flares, but more of them. In future work we will explore the comparative effect on a habitable planet of these two patterns of flaring activity.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 7.2
  • Task 3.1.2 Chemistry Active in Titan Dunes

    Triboelectric reactions of complex organics and water ice are a potential chemical mechanism active in the dunes of Titan. Laboratory experiments have been conducted to simulate and assess how important this possibility can be in the Titan context.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Ice Chemistry Beyond the Solar System

    The molecular inventory available on the prebiotic Earth was likely derived from both terrestrial and extraterrestrial sources. Many molecules of biological importance have their origins via chemical processing in the interstel-lar medium, the material between the stars. Polycyclic aromatic hydrocarbons (PAHs) and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block, the aromatic ben¬zene molecule, has remained elusive for decades. Formamide represents the simplest molecule contain-ing the peptide bond. Conse¬quently, the formamide molecule is of high interest as it is considered as an important precursor in the abiotic synthesis of amino acids, and thus significant to further prebiotic chemistry, in more suitable environments. Ultra-high vacuum low-temperature ice chem-istry experiments have been conducted to understand the formation pathways in the ISM for many astrobiologcally important molecules.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 3.2 3.3 6.2 7.1
  • Fingerprinting Late Additions to the Earth and Moon via the Study of Highly Siderophile Elements in Lunar Impact Melt Rocks

    Three new lunar Apollo 17 impact melt breccias have been examined for highly siderophile element (HSE) abundances and Os isotopic compositions. A now considerable database for impact melt rocks from this site is consistent with a uniform 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. Dynamical calculations and HSE measurements on diogenites suggest that stochastic late accretion can be extrapolated to relatively small bodies, the size of Vesta.

    ROADMAP OBJECTIVES: 1.1
  • High-Resolution Spectroscopy of Comets at Infrared Wavelengths

    Dr. Lucas Paganini has initiated a robust means for quantitative detections of sulfur compounds at submillimeter and infrared (IR). He was awarded 20 hours observing time with the ESO’s sub-millimeter and far-IR Herschel Space Observatory for a proposed investigation on the analysis of OPR and D/H of hydrogen sulfide in comets. And he collaborated extensively on astronomical observations and scientific interpretation of comets 103P/Hartley 2, C/2003 K4 (LINEAR), and 10P/Tempel 2.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Project 3B: In Situ Sulfur Isotope Studies in Archean-Proterozoic Sulfides

    Using new protocols developed at WiscSIMS, we made in situ measurements of three stable isotopes of sulfur (32S, 33S and 34S) in pyrite from the Meteorite Bore Member with unprecedented small spot sizes and accuracy (Williford et al. 2011). We have found a moderate range of S-MIF (> 1‰) in authigenic pyrite before, during and after the Early Proterozoic glaciation as well as a 90‰ range of mass dependent sulfur isotope fractionation (δ34S) larger than any observed in sediments older than 700 Ma. Furthermore, abundant detrital pyrite preserved in one glacial sandstone unit from the Meteorite Bore Member exhibits a range of mass-independent sulfur isotope fractionation slightly larger than the largest published range, from 2.5 Ga sediments of the Hamersley and Transvaal Basins (> 15‰), suggesting that these detrital grains may have originated in rocks of similar age. Taken together, these data imply that the Meteorite Bore Member was deposited during the transitional interval when atmospheric oxygen had risen sufficiently for enhanced continental weathering and ocean sulfate to occur, yet remained low enough to permit the preservation of detrital pyrite and moderate S-MIF.

    ROADMAP OBJECTIVES: 1.1 4.1 4.2 7.1
  • Ice Chemistry of the Solar System

    The overall goals of this project are to understand the chemical evolution of the Solar System, in particular leading to the development of astrobiologically important molecules. This is being achieved by investigation the formation of key organic carbon-, hydrogen-, oxygen-, and nitrogen-bearing (CHON) molecules in ices of Kuiper belt objects by reproducing the space environment experimentally in a unique ultra-high vacuum surface scattering machine. During this reporting period, our team worked on six projects towards our research goal to better understand the ice-based astrochemistry of chemical synthesis for carbon-containing compounds within the solar system. The Keck Astrochemistry Laboratory was also completed during this reporting period.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3 6.2 7.1
  • Task 3.3.1 Solubility of Gases and Organics in Liquid Methane and Ethane

    The solubilities of gases and organics in liquid ethane and methane have been measured.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Task 3.3.2 Precipitation of Organics in Titan Lakes

    Preliminary evaporation-precipitation experiments have been conducted on benzene and acetylene in liquid ethane within the cryostat to simulate processes on Titan lake shores.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • 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 high-resolution ground-based spectroscopy of circumstellar disks and extrasolar planetary transits and secondary eclipses using instruments on the Keck II 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.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1
  • Super-Earth Atmospheres

    In this task we use computer models to study aspects of the atmospheres of extrasolar super-Earths, planets that orbit other stars that are 2-10 times more massive than the Earth. Significant progress was made this year on two models, one that calculates how the atmosphere of the super-Earth is affected by radiative and particles coming from its parent star and one that calculates the surface temperature and change in atmospheric temperature with altitude for superEarth atmospheres.

    ROADMAP OBJECTIVES: 1.1 2.1 3.1
  • Lunar Water, Volatiles, and Differentiation

    Recent discoveries of water in the Moon have important implications for how and when water was delivered to Earth. One way of investigating this is to determine how much water the Moon had when it formed. We do this by searching for water in rocks rich in trace elementsSo far our results indicate that either Earth experienced a second gain of water after the moon formed, or there was an as-yet unexplained loss from the proto-lunar disk.

    ROADMAP OBJECTIVES: 1.1
  • Observations of the Water and Organic Content of Protoplanetary Disks and Comets

    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. It has been a highly productive year. The major overview papers outlining the results from our extensive (>100 disks) Spitzer IRS survey of the molecular emission from the terrestrial planet forming region are now published, and the initial follow-up work with GSFC scientists on the high spectral resolution ground based observations of such emission has just been submitted for publication. We have probed the outer disk’s water emission with the Herschel HIFI instrument, and also measured the D/H ratio in a Jupiter Family Comet for the first time with Herschel – finding a value consistent with that in the Earth’s oceans. Now that ALMA is ramping up toward operations, we look forward to high angular resolution observations of simple organics in the outer regions of disks and comets 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
  • Task 3.3.3 Solubility in Lakes

    Atomistic simulations are being used to study the chemical environment of Titan’s hydrocarbon lakes.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Main Belt Comets

    The distribution of volatiles, and in particular water, in our solar system is a primary determinant of solar system habitability, and understanding how volatiles were distributed throughout the solar system during the era of planetary formation. In particular, the origin of terrestrial water is a fundamental unresolved planetary science issue. There are three leading scenarios for its origin: direct capture from nebular gas, delivery from icy planetesimals, and chemical reactions between oxides in a magma ocean and a tenuous hydrogen atmosphere. Comets provide one of the mechanisms for large-scale transport and delivery of water within our solar system, and asteroids provide another source of volatiles. However, neither comets nor asteroids can explain both Earth’s water and its noble gas inventory. A recently discovered new class of icy bodies in the outer asteroid belt, the Main Belt Comets (MBCs), are comets in near-circular orbits within the asteroid belt that are dynamically decoupled from Jupiter. Dynamics suggest they formed in-situ, beyond the primordial snow line, and as such represent a class of icy bodies that formed at a distance from the Sun that has not yet been studied in detail and which could potentially hold the key to understanding the origin of water on terrestrial habitable worlds. The UH NAI team has been very active in searching for additional MBCs, and characterizing those that are known.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Mars Bulk Composition and Aqueous Alteration

    The composition of Mars, including its total inventory of water, is central to understanding how Mars and the other inner planets formed. Comparison between the abundances of water and volatile elements in Mars, Earth, and Moon are particularly important to understand the source of water to the Earth. We study Martian meteorites, to develop criteria for distinguishing terrestrial from Martian weathering, as a step towards defining the compositions of water solutions on Mars. Our initial results indicate that the martian interior has D/H similar to terrestrial mean ocean water, suggesting similar sources of water to both planets.

    ROADMAP OBJECTIVES: 1.1 2.1
  • Task 3.4.1 Tholin Chemical Analysis Using Nuclear Magnetic Resonance

    The definition and assessment of future flight capable analytical methods for complex organic analysis was pursued, in particular evaluating the potential of nuclear magnetic resonance (NMR).

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Measurements of Primitive Water

    Our research goal is to collect and analyze water that may sample the primordial water accreted by the Earth. This primordial water may reside at the bottom of the Earths mantle and may be sampled from “hotspot” volcanism such at that occurring in Iceland and Hawaii. Glass melt inclusions inside olivine crystals that formed at depth before the lava interacted with surface waters give us the best chance to find this primordial water.

    ROADMAP OBJECTIVES: 1.1 3.1
  • Understanding Past Earth Environments

    For much of the history Earth, life on the planet existed in an environment dramatically 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 and is accessible to detailed study. As such, is 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 of the ancient atmosphere, modeled the effects of clouds on such a planet, studied the sulfur, oxygen and nitrogen cycles, and the 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
  • Task 3.4.2 Tholin Analysis Based on Selective Detection of Functional Groups

    Titan organics comprise a very complex mixture of compounds. Several approaches are being developed that provide targeted detection of specific functional groups, such as nitriles, imines, primary amines, and carbon-carbon multiple bonds.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • Task 3.5.1 Titan Genetics

    An open question is: “What chemical structures might support the genetic component of Darwinian evolution in Titan environments?” This is being approached theoretically and experimentally.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2
  • Remote Sensing of Organic Volatiles in Planetary and Cometary Atmospheres

    We developed state-of-the-art spectroscopic methods to analyze our extensive infrared database of Mars and cometary spectra. In the last two years, we acquired the deepest and most comprehensive search for biomarkers on Mars using powerful infrared high-resolution spectrometers (CRIRES, NIRSPEC, CSHELL) at high-altitude observatories (VLT, Keck-II, NASA-IRTF respectively). In order to analyze this unprecedented wealth of data, we developed highly automated and advanced processing techniques that correct for bad-pixels/cosmic-rays and perform spatial and spectral straightening of anarmophic optics data with milli-pixel precision. We also constructed line-by-line models of the ν7 band of ethane (C2H6), the ν3 and ν2 bands of methanol (CH3OH), we compiled spectral information for H2O and HDO using 5 databases (BT2, VTT, HITEMP, HITRAN and GEISA), and compiled spectral information NH3 using 4 databases (BYT2, TROVE, HITRAN and GEISA). These great advancements have allowed us to understand the infrared spectrum of planetary bodies with unprecedented precision.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 4.1 7.1 7.2
  • Understanding the Early Mars Environment

    By analyzing data from rovers and orbiters, we construct theoretical models to constrain the habitability of current and past Martian environments. VPL has re-analyzed data and called into question the existence of methane and ancient oceans on Mars. In additional, we have contributed to past and future NASA missions such as Phoenix lander and the Curiosity rover,

    ROADMAP OBJECTIVES: 1.1 2.1
  • Task 3.5.2 Energetics of Titan Life

    Thermochemical and dynamic modeling is being used to provide improved constraints on the available chemical energy and trace element fluxes to facilitate potential life on the surface of Titan.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • 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, 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.

    ROADMAP OBJECTIVES: 1.1 1.2
  • Solar System Dynamics

    Understanding how the planets accumulated requires a detailed investigation of the dynamical pro-cesses that were occurring at the time of accretion. UHNAI team members are using dynamical sim-ulations involving many particles to help interpret some of the observable aspects of the modern solar system.

    ROADMAP OBJECTIVES: 1.1
  • Solar System Icy Body Thermal Modeling and Evolutionary Pathways

    Thermal processing on small icy bodies in the solar system (comets, asteroids, Kuiper belt objects) will cause the volatile composition and interior structure to change over time. We seek to understand the evolutionary processes in these bodies so we can understand the observations made in the present epoch and to what extent we can infer the earliest stages of the solar system from these objects.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1
  • The Dynamical Origin and Evolution of COmetary Reservoirs

    Comet taxonomy can only achieve its full significance if the chemical composition of a particular object is linked to its formation location in the solar nebula. This can only be accomplished through a comprehensive, end-to-end dynamical model of the origin and evolution of the comet reservoirs. Such is the goal of this program. Toward these ends, we have recently shown that most of the Oort cloud was probably captured from the proto-planetary disks of other stars when the Sun was in its birth star cluster.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 4.3
  • Water in Planetary Interiors

    We have synthesized samples of high pressure mineral phases that are likely hosts for H, 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.

    ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2