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Project Reports

• Abiotic Nitrogen Cycling

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

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 3.1

• Astronomical Observations of Terrestrial Planet Atmospheres

  In this project we use telescopes and spectrometers on the Earth to study the atmospheres of Venus and Mars to learn more about the current conditions and history of water on these planets. This work also supports ongoing space-based observations of these worlds.

  ROADMAP OBJECTIVES: 1.2 7.2

• 1. From Molecular Clouds to Habitable Planetary Systems

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1

• Climate, Habitability, and the Atmosphere on Early Mars

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

  ROADMAP OBJECTIVES: 1.1 1.2 3.1 6.1 7.1 7.2

• Earth as an Extrasolar Planet

  In this project we are comparing an existing model of the Earth with images and spectra of the Earth obtained from a distance spacecraft. The VPL Earth model uses Earth observing satellite data including atmospheric conditions and cloud cover to simulate both images and spectra of the Earth on a given day of observation. The comparision between the model and data will help us improve our model, and will also provide information on how detectable some of the Earth’s environmental characteristics would be to an observer in another planetary system.

  ROADMAP OBJECTIVES: 1.2 7.2

• Module 2: Formation of Habitable Planetary Systems

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

  ROADMAP OBJECTIVES: 1.1 1.2 3.1

• Expanding the List of Target Stars for Next Generation SETI Searches

  For decades the conventional wisdom considered M dwarf stars unsuitable hosts for habitable planets. We convened an interdisciplinary workshop of thirty scientists to reconsider the issue. They concluded that life could evolve on planets orbiting higher mass M dwarfs. This improves the prospects for finding extraterrestrial life since M dwarfs account for about 75% of all stars. Based on these results, we are preparing a list of more than a million “target” stars for a search for extraterrestrial intelligence (SETI) project.

  ROADMAP OBJECTIVES: 1.1 1.2 4.3 6.2 7.2

• Module 3: Nature of Planetary Systems

  Module 3: the Nature of Planetary Systems focuses on the direct detection and characterization of extrasolar planetary systems. As a complement to the successful radial velocity surveys, direct detection can further our understanding of planets in wide orbits with long periods. The module activity is divided into four areas: development of high contrast techniques, survey observations, and modeling of giant planet spectral energy distributions,
  planning for space missions. A separate report has been made of a study for space observations of Earth to explore observational and interpretive techniques.

  Research Overview
   LAPLACE is developing adaptive optics, differential imaging, and diffraction suppression techniques to optimize sensitivity levels of direct imaging surveys.
   A near infrared survey at H (1.65 μm) band using the VLT and MMT is being carried out to obtain direct images of young planets around nearby stars.
   A thermal infrared survey at L’ (3.8 μm) and M (4.8 μm) band survey using the MMT is being carried out to obtain direct images of older, cooler planets around the nearest stars.
   LAPLACE is developing detailed radiative transfer models of planetary atmospheres to predict flux levels for direct detection of planets using ground-based telescopes, HST, Spitzer, and JWST.
   NASA HQ is funding a study of a space mission PECO, refining a Phase Induced Amplitude Apodization Coronograph (with principal investigator Olivier Guyon, a new hire in Optical Sciences at the University of Arizona). Members of the science team for this mission study include Roger Angel and Neville Woolf of this module, and Michael Meyer of module 2. Other local team members are Glenn Schneider of Steward Observatory and Steven Ridgeway of NOAO. Also James Kasting of the Penn State NAI team is a member. Study partners include JPL, NASA Ames, Lockheed Martin and ITT.

  ROADMAP OBJECTIVES: 1.1 1.2

• Habitable Planets

  This task is concerned with understanding planetary bodies as they form in habitable zones. The planet formation process begins with fragmentation of large molecular clouds into flattened protoplanetary 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

• Modeling Early Earth Environments

  In this project, scientists from different disciplines model the conditions likely to have been found on the Early Earth, prior to 2.3 billion years ago. Specific areas of research include understanding the gases, many biologically produced, and mechanisms that controlled early Earth’s surface temperature, the nature of hazes that shielded the planetary surface from UV and may be responsible for signatures in sulfur isotopes that were left in the rock record, the chemical nature of the Earth’s environment during and after a planet-wide glaciation (a “Snowball event”), the evolution of planetary atmospheres over time due to loss of atmosphere to space, and the use of iron isotopes as a tracer of the oxidative state of the Earth’s ocean over time.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.2 5.1 5.2 5.3 6.1 7.2

• Planetary Habitability

  In this research project, members of the VPL team explore different aspects of planetary habitability, and the detectability of habitability and life, using a combination of theoretical models, astronomical observations and Earth-based field work.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 4.1 5.3 6.1 7.2

• Planetary Surface and Interior Models and Super Earths

  In this task we are developing and using models of a terrestrial planet’s surface and interior to understand
  the evolution of planetary environments. These models allow us to understand how interactions between the
  planetary surface and interior, and life, affect a planet’s atmosphere. New models are also exploring the possible habitability of “super-Earths”, rocky planets that have been found around other stars that can be up to 10 times more massive than our own Earth.

  ROADMAP OBJECTIVES: 1.1 1.2 4.1 5.2 6.1 7.2

• Extrasolar Planets

  D. Deming and summer Intern K. Todorov (Connecticut College) measured the emergent infrared spectrum of the giant transiting exoplanet HAT-P-1, using data from the Spitzer Space Telescope. A future extension of this technique to observations of SuperEarths transiting lower main sequence stars may enable the identification of biomarkers in the emergent spectra of life-bearing terrestrial planets

  ROADMAP OBJECTIVES: 1.2

• VPL Climate and Radiative Transfer Models

  This project develops models of planetary atmospheres and surface temperature to allow us to model extra solar terrestrial planetary environments and to understand what they would look like to distant observers.

  ROADMAP OBJECTIVES: 1.1 1.2

• PSARC (Sigurdsson Report)

  Theoretical modeling of planetary dynamics, in particular the later stages of planet formation and the role of giant planet migration in the formation of terrestrial planets.
  Also, direct detection of planets around burned out stars using existing space based telescopes, and planets around pulsars.

  ROADMAP OBJECTIVES: 1.1 1.2

• Sulfur Biogeochemistry of the Early Earth

  Sulfur is widespread in surface geochemical systems and is abundant in many rock types. It is present in volcanic gases and marine waters, and has served a key role in geobiological processes since the origin of life. Like other low atomic number elements, sulfur isotope ratios in various compounds usually follow predictable mass-dependent fractionation laws; these different mass-dependent isotope fractionations serve as powerful tracers for igneous, metamorphic, sedimentary, hydrothermal and biological processes. Mass-independent sulfur isotope fractionation is a short-wavelength photolytic effect that occurs in space, as well as in gas-phase reactions in atmospheres transparent to deep penetration by ultraviolet light. Crucial aspects of the chemical evolution of the early atmosphere — and the surface zone as a whole — can be followed by mass-independent sulfur isotopes in Archean metasedimentary rocks. Metabolic styles of organisms in response to global changes in surface redox over geologic time can also be traced with multiple S isotopes.

  We have concluded from our various studies over the last year and before to the very inception of the NAI node at Colorado, that all Archean sulfur minerals previously documented for their 34S/32S compositions warrant a comprehensive re-examination of their 32S, 33S, 34S (and 36S), sulfur isotope systematics.

  ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 5.1 5.2 5.3 6.1 7.1 7.2

• Formation and Detection of Hot-Earth Objects in Systems With Close-In Jupiters

  The time of the transit of a planet can be altered by the perturbation of other (planetary) objects in the system. These alterations can be used to identify the presence of the perturbing bodies and are much larger when the perturber and the transiting object are in mean-motion resonances. This project is on mapping the parameter-space of a system of a hot-Jupiter and a terrestrial planet to identify regions where the tererstrial planet will produce the largest transit timing variations.

  ROADMAP OBJECTIVES: 1.1 1.2

• Fu Orionis Eruptions

  FUor eruptions are major accretion events in the lives of young stars,
  probably in young binaries. These very rare events offer important
  insights into the mechanisms by which stars form and circumstellar
  disks evolve. We have studied two such recent cases in detail.

  ROADMAP OBJECTIVES: 1.2

• Newborn Binaries

  Young binaries have orbital properties that still reflect their birth
  conditions. We have studied such binaries in two cases: deeply
  embedded newborn binaries still embedded in their nascent clouds and
  young binaries in the Orion Nebula Cluster.

  ROADMAP OBJECTIVES: 1.2

• The Effect of Lunar-Like Satellites on the Orbital Infrared Lightcurves of Earth-Analog Planets

  We have performed calculations that consider what an Earth-like planet with a large Moon would look like orbiting a distant star. Such observations may one day be possible with space based observatories such as NASA’s Terrestrial Planet Finder (TPF) mission.

  ROADMAP OBJECTIVES: 1.2

• The Vysos Project

  The VYSOS project aims at surveying all the major star forming regions
  all across the entire northern and southern sky for variable young
  stars. Two small survey telescopes have been purchased and provide
  large area shallow observations, and two larger telescopes allow
  deeper more detailed observations. All observations are done
  robotically.

  ROADMAP OBJECTIVES: 1.2

• Variable Young Stellar Objects Survey (VYSOS)

  VYSOS is designed as a survey for variable young stellar objects (protostars and early stars) along the galactic plane and for transiting planets. Out of the about 300 known extrasolar planets just 50 are passing in front of their host star (transits). These transiting planets are highly valuable in scientific terms, because in combination with spectroscopic follow-up observations the absolute values for planetary mass, radius and the geometry of the system can be given. This information allows more detailed follow-up observations by space-based telescopes in order to deduct the composition of the planetary atmosphere and search for prerequisites of life like water in these atmospheres.

  Transiting planets have triggered much theoretical research on planet formation and planetary systems within the past years. The spectrum of densities of planets is not yet fully understood, which has implications for theories about planetary formation as well as atmospheric models.

  ROADMAP OBJECTIVES: 1.1 1.2