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Project Reports

• 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.

  ROADMAP OBJECTIVES: 1.1 3.1

• Amino Acid Alphabet Evolution

  A genetically encoded alphabet of just 20 amino acids has produced the universe of protein structures and functions found throughout Earth’s biosphere. Relationships within this amino acid alphabet are responsible for fundamental biological phenomena, such as protein folding and patterns of molecular evolution. In attempting to unravel these relationships, considerable scientific ingenuity has been spent developing systems to simplify the genetically encoded alphabet of 20 amino acids while minimizing the associated loss of chemical diversity. These efforts present an opportunity to generate a composite picture of the properties that link the amino acids as a set. We are therefore investigating whether different simplification schemes (“simplified amino acid alphabets”), including those derived from very different approaches, can be combined to create a coherent description of amino acid similarity. By understanding the organization and relationships between amino acids on Earth, we hope to shed light on the chemical logic to be expected as a product of evolution in extraterrestrial environments.

  An extensive scientific literature has converged on surprisingly clear agreement that a subset of only around half of the 20 genetically encoded amino acids was likely present from the inception of genetic coding (the “early” amino acids), and an equal sized subset was incorporated through subsequent evolution (the “late” amino acids). A further widespread assumption is that, as the set expanded, natural selection favored the addition of amino acids that extended the range of protein structures and functions. We initiated a quantitative investigation for consilience between these two important ideas.

  ROADMAP OBJECTIVES: 3.2 4.1 4.2 6.2 7.1 7.2

• Charting the Universe of Amino Acid Structures

  More than 3.5 billion years ago, life on our planet evolved a precise alphabet of 20 amino acids to function as building blocks which cells use to construct proteins according to genetic instructions. However, the twenty genetically encoded amino acids are but a tiny fraction of the chemical structures that could plausibly play such a role. Any science of the origins, distribution and future of life in the universe must take into account this larger context of chemical structures. But while astrochemistry, prebiotic chemistry, and bioengineering all hint at the chemical structures it contains, until now this amino acid universe has remained largely unexplored. Efforts to describe the structures it contains, or even estimate their number, have been hampered by the complexity inherent to the combinatorial properties of organic molecules. We have formed a new collaboration to combine European (DLR) advances in computational chemistry with NAI expertise in organic chemistry and amino acid biology to address this gap in current scientific understanding. Our early results have provided the first ever sketch of the amino acid structure universe, showing it to be far larger and more complex than previously supposed. This forms an important milestone in defining and exploring the principles of “universal biology”

  ROADMAP OBJECTIVES: 3.1 3.2 6.2 7.1 7.2

• 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.

  ROADMAP OBJECTIVES: 1.1 1.2

• The VYSOS Project

  The VYSOS project aims at surveying all of the major star forming regions visible from Hawaii for variable young stars. A small survey telescope provides shallow observations over a large area of the sky, and a larger telescope enables deeper, more detailed observations of smaller regions. All observations are done robotically.

  ROADMAP OBJECTIVES: 1.2

• Interdisciplinary Studies of Earth’s Seafloor Biosphere

  The remote deep sediment-buried ocean basaltic crust is Earth’s largest aquifer and host to the least known and potentially one of the most significant biospheres on Earth. CORK observatories have provided unparalleled access to this remote environment. They are enabling groundbreaking research in crustal fluid flow, (bio)geochemical fluid/crustal alteration, and the emerging field of deep crustal biosphere

  ROADMAP OBJECTIVES: 4.1 4.2 5.1 5.2 5.3 6.1 6.2 7.1 7.2

• 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.

  ROADMAP OBJECTIVES: 1.1 3.1

• 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.

  ROADMAP OBJECTIVES: 1.1

• 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

• 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?

  ROADMAP OBJECTIVES: 1.1 2.2

• Permafrost in Hawaii

  Permanent ice can be found on the Hawaiian Islands at extremely few locations and as a result of microclimates. Ice exists in the form of permafrost in craters near the summit of Mauna Kea and in form of ice lakes in lava tubes on Mauna Loa; they are the world’s most isolated ice caves. We investigate the microclimates on the high summits of the Hawaiian Islands that serve as possible analogues to Mars. Exploratory fieldwork has been carried out at four field sites and interdisciplinary collaborations have been developed.

  ROADMAP OBJECTIVES: 2.1 5.3 6.2

• 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

• 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.

  ROADMAP OBJECTIVES: 1.1

• 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.

  ROADMAP OBJECTIVES: 1.1

• 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

• 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.

  ROADMAP OBJECTIVES: 1.1 1.2

• 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.

  ROADMAP OBJECTIVES: 1.1

• 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.

  ROADMAP OBJECTIVES: 1.1 4.3