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2008 Annual Science Report

Astrobiology Roadmap Objective 4.3 Reports Reporting  |  JUL 2007 – JUN 2008

Project Reports

  • 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
  • Effects of Stellar Flares on Atmospheres of Habitable Planets

    Stellar flares, sudden energy bursts from a star, produce a cascade of particles and radiation that can affect that can affect the atmospheres of orbiting planets. Our research is focused on understanding how the atmospheric chemistry of a planet is affected by flares. We want to know if flares can modify the concentrations of compounds that are produced by life and released to the planetary atmosphere and if the ultraviolet radiation during a flare can reach the planetary surface and damage the possible organisms on that planet.

    ROADMAP OBJECTIVES: 1.1 4.3 7.2
  • 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
  • Genomic Record of the Earth’s Early Biosphere (Hedges)

    Our research involves molecular evolutionary genetics in an effort to better understand the relationship between planetary history and the evolution of life. We continue to update our public database TimeTree (www.timetree.org), which presents divergence times of organisms. Most of the work during the past year involved editing and contributing to a book, The Timetree of Life, which summarizes the current state of knowledge in the field and presents new data, with 81 chapters and 105 authors (Oxford University Press, in production).

    ROADMAP OBJECTIVES: 4.1 4.2 4.3
  • Planet Formation and Dynamical Modeling

    In this task, we use computer models of the formation of terrestrial planets and the chemistry in the protoplanetary disk to better understand how carbon, the backbone of life processes, becomes incorporated into
    forming planets. Our planet formation models are also being used to understand planet formation around low-mass stars and binary stars, and how tidal interactions between planet and star can cause a planet’s orbit to evolve
    over time, potentionally taking it into, or out of, the habitable zone.

    ROADMAP OBJECTIVES: 1.1 3.1 4.3
  • Prebiotic Organics From Space

    This project has three components, all aimed to better our understanding of the connection between chemistry in space and the origin of life on Earth and possibly other worlds. Our approach is to trace the formation and evolution of compounds in space, with particular emphasis on identifying those that are interesting from a prebiotic perspective, and understand their possible roles in the origin of life on habitable worlds. We do this by first measuring the spectra and chemistry of materials under simulated space conditions in the laboratory. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes. We also carry out experiments on simulated extraterrestrial materials to analyze extraterrestrial samples returned by NASA missions or that fall to Earth in as meteorites.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.4 4.3 7.1 7.2
  • The High Lakes Project (HLP)

    The High Lakes Project is a multi-disciplinary astrobiological investigation studying high-altitude lakes between 4,200 m and 5,916 m elevation in the Central Andes of Bolivia and Chile. Its primary objective is to understand the impact of increased environmental stress on lake habitats and their evolution during rapid climate change as an analogy to early Mars. Their unique geophysical environment and mostly uncharted ecosystems have added new objectives to the project, including the assessment of the impact of low ozone/high solar irradiance in non-polar aquatic environments, the documentation of poorly known ecosystems, and the quantification of the impact of climate change on lake environment and ecosystem.
    Data from 2003 to 2007 show that solar irradiance is 165% that of sea level with instantaneous UV-B flux reaching 17W/m2. Short UV wavelengths (260-270 nm) were recorded and peaked at 14.6 mW/m2. High solar irradiance occurs in an atmosphere permanently depleted in ozone falling below ozone hole definition for 33-36 days and between 30-35% depletion the rest of the year. The impact of strong UV-B and UV erythemally-weighted daily dose on life is compounded by broad daily temperature variations with sudden and sharp fluctuations. Lake habitat chemistry is highly dynamical with notable changes in yearly ion concentrations and pH resulting from low and variable yearly precipitation. The year-round combination of environmental variables define these lakes as end-members. In such an environment, they host surprisingly abundant and diverse ecosystems including a significant fraction of previously undescribed species of zooplankton, cyanobacterial, and bacterial populations.

    ROADMAP OBJECTIVES: 1.1 2.1 4.1 4.3 5.1 5.2 5.3 6.1 6.2 7.1
  • Carbonate Lithologies on Devon Island, Canada

    During the 2007 field season at the Flashline Mars Arctic Research Station (FMARS) at Haughton Crater on Devon Island, Nunavut, Canada, we collected pale grey impactites (rocks affected by the meteor impact) at the Lake Trinity and Gemini Hills sites. These impactites contain clasts, pieces of the target rocks hit by the meteor. This work is relevant to astrobiology in that it could lead to a greater understanding of impacts with carbonate targets, and contribute to the debate on ALH 84001, the famous Martian meteorite.

    ROADMAP OBJECTIVES: 2.1 4.3
  • FMARS Long Duration Mission: A Simulation of Manned Mars Exploration in an Analogue Environment, Devon Island, Canada

    Seven crewmembers spent four months at the Flashline Mars Arctic Research Station (FMARS) simulating a Mars surface exploration mission on Devon Island in the Canadian High Arctic. We carried out over twenty research projects in biology, geology, mission operations and human factors.

    ROADMAP OBJECTIVES: 2.1 4.3
  • The Delivery of Short-Lived Radionucleides to the Solar System

    I have studied various astrophysical scenarios for the delivery of short-lived radionucleides to star forming cores and planet forming disks in order to explain the observed abundances of 26-Al and 60-Fe in primitive meteorites. The latter, in particular, implies the birth of our solar system closely followed the death of a massive star. It is hard to reconcile the astrophysical and cosmochemical pictures but the most likely birth environment of our Sun was in a giant molecular cloud that formed several generations of stars.

    ROADMAP OBJECTIVES: 1.1 4.3