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2010 Annual Science Report

VPL at University of Washington Reporting  |  SEP 2009 – AUG 2010

Executive Summary

The Virtual Planetary Laboratory

The Virtual Planetary Laboratory is an interdisciplinary research effort focused on answering a single key question in astrobiology: If we were to find a terrestrial planet orbiting a distant star, how would we go about recognizing signs of habitability and life on that planet? This question is relevant to the search for life beyond our Solar System, and the steps towards that are outlined in NASA’s Astrobiology Roadmap Goals 1 and 7. VPL research spans many of the Roadmap objectives, but is most relevant to Objectives 1.1 (Formation and Evolution of Habitable Planets), 1.2 (Indirect and Direct Observations of Extrasolar Habitable Planets) and 7.2 (Biosignatures to be Sought in Nearby Planetary Systems).

Recent observations have brought us much closer to identifying extrasolar environments that could support life. The discovery earlier this year of the planet Gl 581g may be our very first example of a likely rocky planet (~ 3 Earth masses) residing squarely in the circumstellar habitable zone, and potentially able to support life. In the next few years, the successful Kepler Mission will improve our understanding of how common terrestrial planets are in the Galaxy, and the soon-to-be-launched James Webb Space Telescope (JWST) will probe the atmospheric composition of super-Earths. In the longer term, we anticipate the development and launch of spaceborne telescopes that can directly image extrasolar planets as small as the Earth, and obtain multiwavelength photometry and spectroscopy.

The VPL provides a scientific foundation for interpretation of data from extrasolar terrestrial planet detection and characterization missions such as Kepler, JWST and the Terrestrial Planet Finder. To do this, the VPL uses information from Earth’s stages of evolution, and data provided by NASA’s Earth observing and planetary exploration programs, to validate and develop more comprehensive models of terrestrial planets. These models allow us to simulate and explore the likely diversity of extrasolar planet environments in advance of the more challenging observations. These models are primarily used to understand the radiative and gravitational effects of stars on the planets that orbit them. Combinations of model and fieldwork are also used to understand which biologically produced gases can produce a globally-detectable “biosignature”. Finally, models and instrument simulators are used to understand how we can best extract information on a planet’s environment from data that has no direct spatial resolution and may be quite limited in other ways.

The team required to develop and run these models is necessarily highly interdisciplinary. Our research encompasses single discipline efforts that produce results pertinent to our overarching habitability and biosignatures focus, all the way through to highly interdisciplinary efforts where stellar astrophysicists, planetary climate modelers, atmospheric chemists and biologists work together to determine the effects of stellar radiation and gravitation on the habitability of terrestrial planets.

Our Research This Year

Our research can be divided into five main tasks: Solar System Planets, Early Earth and Mars, The Habitable Planet, and The Living Planet. Under each main task, Italicized text refers to a Project Report, with more information.

Solar System Planets

In this task, we use remote-sensing observations of planets in our own Solar System and astronomical observations of extrasolar planets to explore the detectability of planetary characteristics. The Earth still serves as the only known example of a habitable planet, and Venus and Mars show us the end states of alternative terrestrial evolutionary paths.

In the Earth as an Extrasolar Planet project we study the global appearance of the Earth through the course of a day and over seasons, to better understand how to recognize the global imprint of the Earth’s habitability and life. The principal model in this effort is the VPL’s 3D Spectral Earth model, which was further validated this year against phase-dependent EPOXI and ground-based Earthshine measurements of the Earth’s brightness. The model was used it to simulate the Earth’s appearance through an entire orbit, as seen by a distant extrasolar observer (Robinson et al., 2010), and used to disentangle the phase-dependent effects of realistic clouds and ocean reflectivity. We showed that ocean glint is distinguishable from an isotropically scattering surface even in the presence of Earth-like cloud cover. Simulations were also run to look at the detectability of this phenomenon for planet detection and characterization missions (Robinson et al., 2010).

Detecting Glint From an Alien Ocean

This plot shows the increase in reflectivity near crescent phases for an Earth-like planet with an ocean as it orbits around a distant star. The bell-shaped curve shows the Earth’s brightness as a function of phase, modeled by the VPL 3-D spectral Earth model over the course of a year. Full phase is at 180 degrees, crescent phases are closer to 0 and 360 degrees phase. The U-shaped curve shows the model predictions for the Earth’s reflectivity, normalized to that expected from a surface that scatters isotropically (a Lambert sphere). If Earth behaved like a Lambert sphere, then the ratio curve would be a straight line at about 0.3 albedo, at all phases. Instead, our model (and the Earthshine and EPOXI data plotted over it) show that the apparent reflectivity of the Earth deviates strongly from a Lambertian sphere at phases shortward of 90 degrees and longward of 270 degrees. This is due to the addition of both forward scattering from clouds, which dominates this behavior, and specular reflectance from the Earth’s ocean. The difference between the black and grey U-curves shows the effect from ocean, as distinct from clouds, and this difference is plotted in the window below the curves. Our modeling suggests that the presence of a reflecting ocean can be disentangled from the forward-scattering effect of clouds, and may produce an enhancement in the Earth’s reflectivity of as much as 50% at some crescent phases.

For the Astronomical Observations of Planetary Atmospheres and Exoplanets project we performed and/or analyzed ground-based and Spitzer observations of Venus and Titan, and improved models for hot Jupiters and terrestrial exoplanets. VPL team members participated in the Anglo-Australian Telescope Rocky Planet Search, a high-precision radial velocity search, which put constraints on the fraction of stars with super-Earth planets (O’Toole et al., 2009). We also completed a review chapter on terrestrial planet atmospheres (Meadows and Seager, 2010) for the upcoming Exoplanets book.

The Early Mars and Early Earth

In the area of Understanding the Early Mars Environment we completed our interdisciplinary work on climate and photochemical modeling of the effects of SO2 on the early Mars environment. We were able to show that large CO2 abundances, combined with SO2 abundances in excess of 10ppm, could theoretically warm Mars above the freezing point. However, photochemical modeling of a representative 3 bar CO2-SO2-H2O atmosphere revealed that SO2 abundances of just a few ppm would result in dense sulfuric acid aerosol formation. The corresponding increase in planetary albedo outweighs the SO2 greenhouse effect (Figure 2) We conclude that if early Mars was warm it must be due to some other characteristic, other than SO2 (Tian et al., 2010). Additional work on early Mars this year included using energy balance models to simulate the effects of surface temperature on putative Martian rainout. This can serve as a stabilizing feedback to maintain “cool” temperatures at the boundary between evaporation-driven and sublimation-driven hydrological cycles (Breiner et al., 2009) We also provided the first explanation of gas-phase atmospheric production of perchlorate over Earth’s Atacama Desert (Catling et al. 2010) as a first step in understanding perchlorate formation on Mars.

Coupled Photochemical and Climate Model Calculations Including Both SO2 and Sulfate Aerosols

Panel 'A’-aerosol extinction optical depth at 5500 Å. The solid curve is for sulfate aerosols under normal (terrestrial) rainout conditions. The diamond symbols are for S8 aerosols under normal rainout condition. The crosses are for sulfate aerosols for rainout reduced by a factor of 100. The star is for sulfate aerosols for rainout reduced by a factor of 1000. Panel 'B’-planetary albedo. Panel 'C’-surface temperature. Panel 'D’-combined (SO2+H2S) fluxes, with the same symbols as those in panel A. These calculations are for a 3-bar atmosphere with S/S0 = 0.75. Dotted curves in panels B and C show similar calculations in which sulfate aerosols are neglected

For Understanding the Earth Earth we made further progress in developing a techniques to put geological constraints on the Archean atmospheric pressure. These involve measuring and modeling gas bubble sizes in sea level basalt flows, and from preserved raindrop impact craters (Som and Buick, in progress). Goldblatt et al., (2009) discussed the possibility that there was more nitrogen in the Archean atmosphere than today, which would have enhanced greenhouse warming via pressure broadening. Goldblatt & Zahnle (2010) have explored how clouds could affect the Faint Young Sun paradox. VPL team member Sleep (Rosing et al. 2010) has suggested a new constraint on pCO2 in the Archean, which would make this paradox harder to solve. Tian and Kasting (manuscript in review) are suggesting that NH3 may have been relevant as an Archean greenhouse gas, contrary to earlier work. Catling reviewed the importance of the oxygen cycle in determining planetary redox state (Catling, 2010). Work in progress by Haqq-Misra uses a passive tracer in a general circulation model (GCM) to constrain the transport of photolytically generated oxygen down to the planetary surface. Additionally we enhanced our atmospheric chemistry model to include isotopic sulfur species and sub-Angstrom wavelength resolution The model predicts magnitudes of sulfur fractionation that are at odds with other recent papers, and show that the situation is more complex that originally described (Claire & Kasting, 2010; Postdoctoral Fellow Report: Mark Claire).

The Stromatolites In the Desert: Analogs to Other Worlds project is a field component (led by J. Siefert) that complements our Archean modeling research by studying freshwater stromatolites, an ancient form of life, in phosphorous poor environments found at Cuatro Cienegas, Mexico. A successful field trip was executed this year with in situ studies of organism calcification and the collection of samples. The samples are being naturalized and prepared for experiments under higher atmospheric CO2 concentrations.

The Habitable Planet

In this task we explore the many planetary and planetary system processes and characteristics required to initiate and maintain planetary habitability.

The Formation of Terrestrial Planets project uses detailed numerical simulations to model formation of rocky worlds. This year, we published models of the rate of planet growth from 1km planetesimals, showing that it proceeds quickly, and that terrestrial exoplanets, which could provide sites for life, may be common (Barnes et al., 2009). We performed simulations to explore how the shape of outer belts of minor planets in a planetary system are sculpted by the architecture of interior planets (Raymond et al 2010).

The Delivery of Volatiles project encompases modeling of the dynamical delivery of volatiles during the planet formation process, and the fate of carbon and volatiles on atmospheric entry. Results this year include publication of a new model showing polycyclic aromatic hydrocarbons (PAHs) to be the dominant form of carbon included in terrestrial planet formation (Kress et al., 2009), and a laboratory investigation of meteor/atmosphere reactions that shows that complex organics containing aromatic bonds can undergo further reaction in the upper atmosphere.
Significant progress was made in Dynamical Effects on Planetary Habitability this year. We published work demonstrating that comets are unlikely to have produced more than one mass extinction event on Earth (Kaib & Quinn 2010). We also published a new empirical description of where in a planetary system orbits will be stable, which allowed us to calculate the fraction of known habitable zones that can support a terrestrial planet (Kopparapu & Barnes 2010). Team members were instrumental in the discovery that two known exoplanets have orbital planes inclined by 30 degrees to each other (McArthur, Benedict, Barnes et al 2010). Work is ongoing to explain this phenomenon. Additionally, progress was made in estimating the tidal heating of known exoplanets, coupling tidal evolution to atmospheric mass loss, and contributions to radial velocity detection of planets. Other ongoing work includes modeling of systems with planets on orbits with high inclination; coupling orbital oscillations to obliquity and climate; modeling of planetary obliquity under the influence of tides; and the development of a coupled interior-tidal model.

The Planetary Surface and Interior Models and Super-Earths project is concerned with planetary geological processes that may affect habitability. We continued to develop and use a reactive transport model to simulate weathering at planetary surfaces, expanding the CO2 reaction set and adding soil-atmosphere volatile exchange for 8 gases (Bolton, work in progress). We have made significant progress towards an integrated model to simulate the thermal evolution of planets, including super-Earths, that are subjected to tidal heating (Rye and Barnes, work in progress). In other work we have found that Earth’s cratons are near the transition from chemical lid to stagnant lid, suggesting that chemical lids may easily develop on super-earths. We have also found that life may significantly affect the geology of a planet, as well as the atmosphere, with work that suggests that life greatly increases sulfur in arc volcanics (Sleep et al., 2010).

In the Super-Earth Atmospheres project we are developing the capabilities to model the atmospheres and spectra of super-Earths using atmospheric escape, climate, chemistry and radiative transfer models. Work this year included atmospheric escape modeling for super-Earth planets in M star habitable zones, indicating that these planets could lose a significant fraction of their volatile inventory if not dominated by CO2 (Tian et al., in progress). Work also continued on a generalized climate model for terrestrial planets and modifications to our radiative transfer model to allow us to simulate transit transmission spectra.

In the Stellar Effects on Planetary Habitability project we look at the radiative effects of the parent star on planetary habitability. We worked this year to enhance a model of the evolution of Solar flux over the age of the Solar System as input to models of the evolution of planetary atmospheres (Claire, 2010). We also completed and published our work on the effect of stellar flare UV and particles on planetary habitability for Earth-like M dwarf planets (Segura et al., 2010). This photochemical-climate modeling shows that the incoming UV has very little effect on ozone (Figure 3), but particle driven chemistry can severely deplete a planet’s protective ozone layer. However, the corresponding enhanced UV fluxes at the planet’s surface only exceed those received on Earth for about 100 seconds, minimizing flare damage. We are moving into the next phase of this research by modeling the effect of flares on CO2-rich planetary atmospheres.

Time evolution of the ozone column depth compared to the initial steady state before, during, and after a big UV flare event. The lines show simulations made with different time steps after the flare ended. Times used for each run are listed
in the figure (Segura et al. 2010).

Time evolution of the ozone column depth compared to the initial steady state. These results show the combined influence of the flare’s incident UV radiation and a proton event at the peak of the flare. Line with diamonds: O3 fraction
change for a simultaneous UV and proton flux peak. Line with crosses: O3 fraction change for a proton event with a maximum delayed by 889 s with respect to the UV flare peak. Vertical dotted lines indicate the time for the peak of the UV
flare and the end of the UV flare (Segura et al. 2010).

Flux received at the top of the atmosphere of a planet on the AD Leo habitable zone (0.16 AU). The dotted line is the solar flux received by Earth. Times listed on the right lower corner of each panel correspond to the flare fluxes plotted on that
panel. AD Leo spectrum during quiescence is always shown in a black continuous line to be used as a reference (Segura et al. 2010).

The Living Planet

The VPL Life Modules task encompasses development of 3-D ecosystem models to look at biosphere/planet interactions. This year we collaboratively incorporated the NASA Ocean Biogeochemistry Model (NOBM) of VPL Co-I Gregg into the ocean model of the GISS GCM, providing the capability to model a full carbon cycle system. We are continuing evaluation and testing of the coupled carbon dynamics. The NOBM, coupled to an ocean general circulation model was used to explore conditions for early life on Earth. Simulations were run with cyanobacteria as the only photosynthesizers (modern diatoms, coccolithophores and chlorophytes were removed) showing that the early Earth would have had 19% less productivity and 35% more nitrate due to slower growth of the cyanobacteria. In addition, our Ent ecosystem model’s canopy radiative transfer scheme for mixed canopies and clumped foliage was published (Kiang et al. 2010)

The Thermodynamic efficiency of electron-transfer reactions in the Chlorophyll d-containing cyanobacterium, Acharyochloris marina and Postdoctoral Report: Steve Mielke project reports describe a laboratory-based project to explore the efficiency of photosynthesis at the extreme red end of the spectrum, using chlorophyll d in the bacterium A. marina, as a means of understanding whether photosynthesis might be possible on planets around M dwarfs, or on haze-covered planets. Recent results indicate that chlorophyll d is just as efficient as chlorophyll a, showing that photosynthesis can procede efficiently at far red wavelengths, and implying that we have not yet found the wavelength limit for oxygenic photosynthesis.

This year in the Detectability of Biosignatures task we continued our research into remote-sensing biosignatures for metabolisms other than oxygenic photosynthesis. This year we used photochemical and radiative transfer modeling to explore the potential of various sulfur-bearing biogenic gases to act as biosignatures for anoxic planets similar to the early Earth, and in orbit around stars of different spectral type (Domagal-Goldman, et al., submitted). For this type of biosphere, we find that the methyl mercaptan and ethane signatures are most likely to build up to detectable levels on planets orbiting M dwarf stars. (Figure 4). We also started research to explore the potential for abiotic false positives from ozone, for early Earth like planets orbiting cooler stars. In parallel, we have obtained and are now running simulators for Terrestrial Planet Finder Coronograph (S. Heap and D. Lindler) and Interferometer (T. Velusamy) mission concepts. We are using these simulators to explore the detectability of signs of habitability and biosignatures from oxygenic photosynthetic, as well as the other metabolisms described here (Evans et al., 2010).

<span class="caps">MIR</span> Spectra of Sulfur-Based Biosignatures

Mid-infrared spectra showing the position and relative strengths of absorption bands of biogenic gases produced by sulfur-based metabolisms. The three panels show the results for a planet orbiting the Sun, an active M dwarf and an M dwarf with no stellar activity. The difference colored spectra in each panel correspond to different levels of planetary surface flux of biologically generated sulfur gases or methane. The most detectable feature of the sulfur metabolism is ethane, which can be produced both by methane photolysis, and the release of methyl groups from biologically generated sulfur gases. Quantifying the amount of methane in the planet’s atmosphere may help to discriminate between these two sources.

As part of the on-going VPL Community Tools, we have developed a comprehensive database of molecular, stellar, pigment, and mineral spectra useful in developing extrasolar planet climate models and interpreting the results of NASAs current and future planet-finding missions. This year work focused on improving our molecular line lists for gases such as methane and ethane (lead by Brown), and significantly expanding our photosynthetic pigment database (lead by Kiang).

EPO and Education Efforts

This year in EPO we made significant progress on the Extreme Planet Makeover Interactive, which allows users to change the appearance and habitability of a planet they create by modifying factors such as star-planet distance, and planetary age and size. Initial development of our Night Sky Network Astrobiology Outreach Toolkit has been completed, and the kit is currently in test phase, with an anticipated rollout date to all qualified member astronomy clubs in the summer of 2011. We have also started a partnership with Lakewood High School in Washington state to pioneer a high school level Astrobiology course. Additionally VPL scientists taught astrobiology courses to nonscience majors, and engaged members of the public via public talks, museum exhibits and media interviews.

Publications

  • Bailey, J., Ahlsved, L., & Meadows, V. S. (2011). The near-IR spectrum of Titan modeled with an improved methane line list. Icarus, 213(1), 218–232. doi:10.1016/j.icarus.2011.02.009

  • Barnes, R., Quinn, T. R., Lissauer, J. J., & Richardson, D. C. (2009). N-Body simulations of growth from 1km planetesimals at 0.4AU. Icarus, 203(2), 626–643. doi:10.1016/j.icarus.2009.03.042

  • Barnes, R., Raymond, S. N., Greenberg, R., Jackson, B., & Kaib, N. A. (2010). CoRoT-7b: SUPER-EARTH OR SUPER-Io?. The Astrophysical Journal, 709(2), L95–L98. doi:10.1088/2041-8205/709/2/l95

  • Benedict, G. F., McArthur, B. E., Bean, J. L., Barnes, R., Harrison, T. E., Hatzes, A., … Nelan, E. P. (2010). THE MASS OF HD 38529c FROM HUBBLE SPACE TELESCOPE ASTROMETRY AND HIGH-PRECISION RADIAL VELOCITIES. The Astronomical Journal, 139(5), 1844–1856. doi:10.1088/0004-6256/139/5/1844

  • Buick, R. (2010). Early life: Ancient acritarchs. Nature, 463(7283), 885–886. doi:10.1038/463885a

  • Catling, D. C., & Zahnle, K. J. (2009). The Planetary Air Leak. Scientific American, 300(5), 36–43. doi:10.1038/scientificamerican0509-36

  • Catling, D. C., Claire, M. W., Zahnle, K. J., Quinn, R. C., Clark, B. C., Hecht, M. H., & Kounaves, S. (2010). Atmospheric origins of perchlorate on Mars and in the Atacama. Journal of Geophysical Research, 115. doi:10.1029/2009je003425

  • Cerritos, R., Eguiarte, L. E., Avitia, M., Siefert, J., Travisano, M., Rodríguez-Verdugo, A., & Souza, V. (2010). Diversity of culturable thermo-resistant aquatic bacteria along an environmental gradient in Cuatro Ciénegas, Coahuila, México. Antonie van Leeuwenhoek, 99(2), 303–318. doi:10.1007/s10482-010-9490-9

  • Cowan, N. B., Agol, E., Meadows, V. S., Robinson, T., Livengood, T. A., Deming, D., … Charbonneau, D. (2009). ALIEN MAPS OF AN OCEAN-BEARING WORLD. The Astrophysical Journal, 700(2), 915–923. doi:10.1088/0004-637x/700/2/915

  • Dadic, R., Light, B., & Warren, S. G. (2010). Migration of air bubbles in ice under a temperature gradient, with application to “Snowball Earth”. Journal of Geophysical Research, 115(D18), None. doi:10.1029/2010jd014148

  • Domagal-Goldman, S. D., Meadows, V. S., Claire, M. W., & Kasting, J. F. (2011). Using Biogenic Sulfur Gases as Remotely Detectable Biosignatures on Anoxic Planets. Astrobiology, 11(5), 419–441. doi:10.1089/ast.2010.0509

  • Dressing, C. D., Spiegel, D. S., Scharf, C. A., Menou, K., & Raymond, S. N. (2010). HABITABLE CLIMATES: THE INFLUENCE OF ECCENTRICITY. The Astrophysical Journal, 721(2), 1295–1307. doi:10.1088/0004-637x/721/2/1295

  • Fleming, S. W., Ge, J., Mahadevan, S., Lee, B., Eastman, J. D., Siverd, R. J., … Watters, S. (2010). DISCOVERY OF A LOW-MASS COMPANION TO A METAL-RICH F STAR WITH THE MARVELS PILOT PROJECT. The Astrophysical Journal, 718(2), 1186–1199. doi:10.1088/0004-637x/718/2/1186

  • Goldblatt, C., & Zahnle, K. J. (2010). Clouds and the Faint Young Sun Paradox. Climate of the Past Discussions, 6(3), 1163–1207. doi:10.5194/cpd-6-1163-2010

  • Goldblatt, C., Claire, M. W., Lenton, T. M., Matthews, A. J., Watson, A. J., & Zahnle, K. J. (2009). Nitrogen-enhanced greenhouse warming on early Earth. Nature Geosci, 2(12), 891–896. doi:10.1038/ngeo692

  • Goldblatt, C., Zahnle, K. J., Sleep, N. H., & Nisbet, E. G. (2009). The Eons of Chaos and Hades. Solid Earth Discuss., 1(1), 47–53. doi:10.5194/sed-1-47-2009

  • Halevy, I., Johnston, D. T., & Schrag, D. P. (2010). Explaining the Structure of the Archean Mass-Independent Sulfur Isotope Record. Science, 329(5988), 204–207. doi:10.1126/science.1190298

  • Heller, R., Jackson, B., Barnes, R., Greenberg, R., & Homeier, D. (2010). Tidal effects on brown dwarfs: application to the eclipsing binary 2MASS J05352184-0546085. A&A, 514, A22. doi:10.1051/0004-6361/200912826

  • Jackson, B., Miller, N., Barnes, R., Raymond, S. N., Fortney, J. J., & Greenberg, R. (2010). The roles of tidal evolution and evaporative mass loss in the origin of CoRoT-7 b. Monthly Notices of the Royal Astronomical Society, 407(2), 910–922. doi:10.1111/j.1365-2966.2010.17012.x

  • Jones, H. R. A., Butler, R. P., Tinney, C. G., O’Toole, S., Wittenmyer, R., Henry, G. W., … Jenkins, J. S. (2010). A long-period planet orbiting a nearby Sun-like star. Monthly Notices of the Royal Astronomical Society, 403(4), 1703–1713. doi:10.1111/j.1365-2966.2009.16232.x

  • Kaib, N. A., & Quinn, T. (2009). Reassessing the Source of Long-Period Comets. Science, 325(5945), 1234–1236. doi:10.1126/science.1172676

  • Kasting, J. F. (2010). Early Earth: Faint young Sun redux. Nature, 464(7289), 687–689. doi:10.1038/464687a

  • Kopparapu, R. K., & Barnes, R. (2010). STABILITY ANALYSIS OF SINGLE-PLANET SYSTEMS AND THEIR HABITABLE ZONES. The Astrophysical Journal, 716(2), 1336–1344. doi:10.1088/0004-637x/716/2/1336

  • Kress, M. E., Tielens, A. G. G. M., & Frenklach, M. (2010). The ‘soot line’: Destruction of presolar polycyclic aromatic hydrocarbons in the terrestrial planet-forming region of disks. Advances in Space Research, 46(1), 44–49. doi:10.1016/j.asr.2010.02.004

  • Lunine, J. I., O’Brien, D. P., Raymond, S. N., Morbidelli, A., Quinn, T., & Graps, A. L. (2011). Dynamical Models of Terrestrial Planet Formation. Advanced Science Letters, 4(2), 325–338. doi:10.1166/asl.2011.1212

  • Marion, G. M., Catling, D. C., Zahnle, K. J., & Claire, M. W. (2010). Modeling aqueous perchlorate chemistries with applications to Mars. Icarus, 207(2), 675–685. doi:10.1016/j.icarus.2009.12.003

  • McArthur, B. E., Benedict, G. F., Barnes, R., Martioli, E., Korzennik, S., Nelan, E., & Paul Butler, R. (2010). NEW OBSERVATIONAL CONSTRAINTS ON THE υ ANDROMEDAE SYSTEM WITH DATA FROM THE HUBBLE SPACE TELESCOPE AND HOBBY-EBERLY TELESCOPE. The Astrophysical Journal, 715(2), 1203–1220. doi:10.1088/0004-637x/715/2/1203

  • Ni-Meister, W., Yang, W., & Kiang, N. Y. (2010). A clumped-foliage canopy radiative transfer model for a global dynamic terrestrial ecosystem model. I: Theory. Agricultural and Forest Meteorology, 150(7-8), 881–894. doi:10.1016/j.agrformet.2010.02.009

  • O’Toole, S. J., Jones, H. R. A., Tinney, C. G., Butler, R. P., Marcy, G. W., Carter, B., … Wittenmyer, R. A. (2009). THE FREQUENCY OF LOW-MASS EXOPLANETS. The Astrophysical Journal, 701(2), 1732–1741. doi:10.1088/0004-637x/701/2/1732

  • Quinn, T., Perrine, R. P., Richardson, D. C., & Barnes, R. (2010). A SYMPLECTIC INTEGRATOR FOR HILL’S EQUATIONS. The Astronomical Journal, 139(2), 803–807. doi:10.1088/0004-6256/139/2/803

  • Raymond, S. N., Armitage, P. J., & Gorelick, N. (2010). PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS. The Astrophysical Journal, 711(2), 772–795. doi:10.1088/0004-637x/711/2/772

  • Ribas, I., Guinan, E. F., Gudel, M., & Audard, M. (2005). Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres. I. High‐Energy Irradiances (1–1700 A). The Astrophysical Journal, 622(1), 680–694. doi:10.1086/427977

  • Robinson, T. D., Meadows, V. S., & Crisp, D. (2010). DETECTING OCEANS ON EXTRASOLAR PLANETS USING THE GLINT EFFECT. The Astrophysical Journal, 721(1), L67–L71. doi:10.1088/2041-8205/721/1/l67

  • Robinson, T. D., Meadows, V. S., Crisp, D., Deming, D., A’Hearn, M. F., Charbonneau, D., … Wellnitz, D. D. (2011). Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations. Astrobiology, 11(5), 393–408. doi:10.1089/ast.2011.0642

  • Rosing, M. T., Bird, D. K., Sleep, N. H., & Bjerrum, C. J. (2010). No climate paradox under the faint early Sun. Nature, 464(7289), 744–747. doi:10.1038/nature08955

  • Segura, A., Walkowicz, L. M., Meadows, V., Kasting, J., & Hawley, S. (2010). The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M Dwarf. Astrobiology, 10(7), 751–771. doi:10.1089/ast.2009.0376

  • Sleep, N. H. (2009). Stagnant lid convection and carbonate metasomatism of the deep continental lithosphere. Geochem. Geophys. Geosyst., 10(11), n/a–n/a. doi:10.1029/2009gc002702

  • Sleep, N. H. (2010). The Hadean-Archaean Environment. Cold Spring Harbor Perspectives in Biology, 2(6), a002527–a002527. doi:10.1101/cshperspect.a002527

  • Spiegel, D. S., Raymond, S. N., Dressing, C. D., Scharf, C. A., & Mitchell, J. L. (2010). GENERALIZED MILANKOVITCH CYCLES AND LONG-TERM CLIMATIC HABITABILITY. The Astrophysical Journal, 721(2), 1308–1318. doi:10.1088/0004-637x/721/2/1308

  • Tian, F., Claire, M. W., Haqq-Misra, J. D., Smith, M., Crisp, D. C., Catling, D., … Kasting, J. F. (2010). Photochemical and climate consequences of sulfur outgassing on early Mars. Earth and Planetary Science Letters, 295(3-4), 412–418. doi:10.1016/j.epsl.2010.04.016

  • Ueno, Y., Johnson, M. S., Danielache, S. O., Eskebjerg, C., Pandey, A., & Yoshida, N. (2009). Geological sulfur isotopes indicate elevated OCS in the Archean atmosphere, solving faint young sun paradox. Proceedings of the National Academy of Sciences, 106(35), 14784–14789. doi:10.1073/pnas.0903518106

  • Vogt, S. S., Wittenmyer, R. A., Butler, R. P., O’Toole, S., Henry, G. W., Rivera, E. J., … Batygin, K. (2009). A SUPER-EARTH AND TWO NEPTUNES ORBITING THE NEARBY SUN-LIKE STAR 61 VIRGINIS. The Astrophysical Journal, 708(2), 1366–1375. doi:10.1088/0004-637x/708/2/1366

  • Yang, W., Ni-Meister, W., Kiang, N. Y., Moorcroft, P. R., Strahler, A. H., & Oliphant, A. (2010). A clumped-foliage canopy radiative transfer model for a Global Dynamic Terrestrial Ecosystem Model II: Comparison to measurements. Agricultural and Forest Meteorology, 150(7-8), 895–907. doi:10.1016/j.agrformet.2010.02.008

  • Zugger, M. E., Kasting, J. F., Williams, D. M., Kane, T. J., & Philbrick, C. R. (2010). LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES. The Astrophysical Journal, 723(2), 1168–1179. doi:10.1088/0004-637x/723/2/1168

  • Anbar.  (2010).  ``An Archean Biosphere Initiative”.
  • Barnes, R.  (2010).  Formation and Evolution of Exoplanets.  Wiley-VCH. Berlin.
  • Barnes, R.  (2010).  Planet-Planet Interactions.  In: Barnes, R. (Eds.).  In Formation and Evolution of Exoplanets.  Berlin: Wiley-VCH Publishing.
  • Barnes, R.  (2010).  Tidal Constraints on Planetary Habitability.  NAI Workshop ``Revisiting the Habitable Zone,’'.  Seattle, WA.
  • Barnes, R., Jackson, B., Greenberg, R., Raymond, S.N. & Heller, R.  (2010).  Tidal Constraints on Planetary Habitability, in Pathways Toward Habitable Planets,.  Pathways Toward Habitable Planets.  ASPC.
  • Barnes, R., Jackson, B., Heller, R., Greenberg, R. & Raymond, S.N.  (2010).  Tidal Effects on the Habitability of Exoplanets: The Case of GJ 581 d.  Astrobiology Science Conference 2010: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond.
  • Barnes, R., Jackson, B., Raymond, S. & Greenberg, R.  (2010).  The Role of Planetary System Architecture in Planetary Habitability.  Am. Astron. Soc. Meeting # 216.  Miami, FL.
  • Breiner, J., Domagal-Goldman, S. & Claire, M.W.  (2009).  Modeling rainout on ancient Mars as a function of atmospheric forcings.  AGU Fall Meeting.  San Francisco, CA.
  • Buick, R.  (2010).  The early evolution of photosynthesis [Public Talk 05/27/2010].  Invited Seminar.
  • Buick, R.  (2010).  The early evolution of the biogeochemical nitrogen cycle [Public Talk 05/17/2010].  Seminar (Invited).
  • Catling, D.C. & Bergsman, D.S.  (2010).  On detecting exoplanet biospheres from atmospheric chemical disequilibrium.  Astrobiology Science Conference.
  • Catling, D.C.  (2009).  Atmospheric evolution of Mars.  In: Gornitz, V. (Eds.).  Encyclopedia of Paleoclimatology and Ancient Environments.  Springer, Dordrecht.
  • Catling, D.C.  (Submitted (2010)).  Oxygenation of the Earth’s atmosphere.  In: Gargaud, M. (Eds.).  Encyclopedia of Astrobiology.  Springer.
  • Claire, M. & Kasting, J.  (2010).  `The Magnitude of Atmospheric Sulfur Mass-Independent Fractionation”.  ABSciCon 2010.
  • Claire, M. & Kasting, J.  (2010).  ``Variations in the Magnitude of Non Mass Dependent Sulfur Fractionation in the Archean Atmosphere”.
  • Claire, M. & Kasting, J.  (2010a).  The Magnitude of Atmospheric Sulfur Mass-Independent Fractionation.  ABSciCon.  Houston, TX.
  • Claire, M. & Kasting, J.  (2010b).  Variations in the Magnitude of Non Mass Dependent Sulfur Fractionation in the Archean Atmosphere’.  Goldschmidt.  Knoxville, TN.
  • Claire, M., Catling, D. & Cohen, M.  (2010).  ``The Evolution Of Solar Flux From 2nm To 160 Microns: Quantitative Estimates For Planetary Studies’.  Bulletin of the American Astronomical Society, 41: p. 433.
  • Claire, M., Catling, D. & Cohen, M.  (2010).  ``The Evolution Of Solar Flux From 2nm To 160 Microns: Quantitative Estimates For Planetary Studies”.
  • Crow, C., McFadden, L.A., Robinson, T., Meadows, V., Livengood, T.A., Hewagama, T., Barry, R.K., Deming, L.D. & Lisse, C.M.  (2010).  American Astronomical Society, DPS meeting #42.
  • Danielache, S.O., Eskebjerg, C., Johnson, M.S., Ueno, Y. & Yoshida, N.  (2008).  High-precision spectroscopy of S-32, S-33, and S-34 sulfur dioxide: Ultraviolet absorption cross sections and isotope effects.  Journal of Geophysical Research-Atmospheres, 113(D17): -.  doi:Artn D17314 Doi 10.1029/2007jd009695
  • Demarines, J., Cash, W., Domagal-Goldman, S. & Meadows, V.  (2010).  Remote Detection of Biosignatures of Primitive and Evolved Life on Extrasolar Planets.
  • Domagal-Goldman, S., Meadows, V.S., Kasting, J. & Claire, M.  (2010).  Astronomical Biosignatures for Sulfur-Rich Anoxic Biospheres.
  • Domagal-Goldman, S.D. & Meadows, V.S.  (2010).  False positives for life: A new meathod for abiotic ozone accumulation in exoplanet atmospheres.
  • Evans, N., Meadows, V.S. & Domagal-Goldman, S.  (2010).  Exploring the Detectability of Terrestrial Exoplanet Characteristics.
  • Fleming, S.W.  (2010).  Binary Science from the MARVELS Pilot Project: Detection of a Candidate Substellar Companion and Identification of Eclipsing Binaries with Archival SuperWASP Data.  Am. Astron. Soc. Meeting # 215.  Washington, DC.
  • Garvin, J., Buick, R., Anbar, A.D., Arnold, G.L. & Kaufman, A.J.  (2009).  Response to “Analysis of Archean Nitrogen Isotopic Data”.  Science.
  • Greenberg, R. & Jackson, B.  (2009).  Tidal Heating and the Boundaries of the Habitable Zone.  Am. Geophys. U.  San Francisco, CA.
  • Güdel, M. & Kasting, J.F.  (In Press).  The young Sun and its influence on planetary atmospheres.  In: Gargaud, M., Lopez-Garcia, P. & Martin, H. (Eds.).  Origin of Life: an Astrobiology Perspective.  Cambridge Univ. Press.
  • Haqq-Misra, J.  (2010).  A Meteorological Condition for Atmospheric Stability on Synchronously Rotating Planets (Abstract).  Revisiting the Habitable Zone.  Talaris Conference Center, Seattle, WA.
  • Iraci, M.E.K.C.L.B.G.D.C.A.R.P.L.T.  (2010).  “Atmospheric chemistry of micrometeoritic organic compounds”.  Meteoroids 2010.  Breckenridge, CO.
  • Jackson, B., Barnes, R. & Greenberg, R.  (2010).  Tides and Exoplanets.  In: Barnes, R. (Eds.).  In Formation and Evolution of Exoplanets,.  Berlin: Wiley-VCH Publishing.
  • Jackson, B., Barnes, R., Raymond, S., Fortney, J. & Greenberg, R.  (2010).  Is CoRoT-7 B the Remnant Core of an Evaporated Gas Giant?  Am. Astron. Soc. Meeting \# 215.
  • Jackson, B., Raymond, S., Greenberg, R. & Barnes, R.  (2009).  Effects of Secular, Resonant and Tidal Perturbations on Planetary Habitability.  Am. Astron. Soc. Div. Plan. Sci. Meeting #41.  Fajardo, PR.
  • Jackson, B., Raymond, S., Greenberg, R. & Barnes, R.  (2009).  The Role of Planetary System Architecture in Planetary Habitability.  Am. Geophys. U.  San Francisco, CA.
  • Kasting, J.F.  (2010).  How to Find a Habitable Planet.  Princeton, NJ: Princeton University.
  • Kasting, J.F.  (2010).  How to find a habitable planet, in Pathways Towards Habitable Planets.  ASP Conf. Series.  Astron. Soc. Pacific, San Francisco.
  • Kasting, J.F.  (2010).  Stellar radiative effects on habitable zones.  Workshop on Redefining the Habitable Zone.  Seattle, WA.
  • Kasting, J.F.  (In Press).  How to find a habitable planet.  Pathways Towards Habitable Planets.
  • Kasting, J.F.  (In Press).  The global O2 cycle.  In: Konhauser, K., Knoll, A. & Canfield, D. (Eds.).  Fundamentals of Geobiology.  Blackwell.
  • Khalfa, N., Meadows, V.S. & Domagal-Goldman, S.D.  (2009).  Optimizing Spectral Resolution and Observation Time for Measurements of Habitability.  AGU Fall Meeting.
  • Kiang, N.  (2010).  The Virtual Planetary Laboratory Spectral Library.  International Congress of Photosynthesis.  Beijing, China.
  • Kiang, N.Y., Aleinov, I., Ni-Meister, W., Moorcroft, P.R. & Koster, R.  (2010).  Coupled Dynamic Global Vegetation Models (DGVMs) for Climate Simulations and Data to Constrain Them [Public Talk September 16, 2010].  Science Visitor and Colloquium Program – Earth Science Seminar Series.
  • Kiang, N.Y., Mielke, S., Mauzerall, D., Blankenship, R.E. & Gunner, M.  (2009).  Efficiency of photon energy use for life processes: implications for spectral biosignatures [Public Talk November 10-13, 2009].  Innovative Approaches to Exoplanet Spectra Workshop.
  • Kiang, N.Y., Mielke, S., Mauzerall, D., Blankenship, R.E. & Gunner, M.  (2009).  Efficiency of photon energy use for life processes: implications for spectral biosignatures [Public Talk November 19, 2009].  Center for Exoplanet Science Colloquium.
  • Kiang, N.Y., Yang, W.Z., Ni-Meister, W., Moorcroft, P.R. & Aleinov, I.  (2009).  Vegetation community structure in a mixed-canopy dynamic global terrestrial ecosystem model: sensitivity of biosphere-atmosphere exchange to canopy vertical stratification and demography [Public Talk December 13-17, 2009].  American Geophysical Union, Fall Meeting.
  • Kopparapu, R. & Barnes, R.  (2009).  Dynamical Stability of Terrestrial Mass Planets in and Around the Habitable Zones of Single Planet Systems.  Am. Geophys. U.  San Francisco, CA.
  • Kopparapu, R. & Barnes, R.  (2010).  Dynamical Stability of Terrestrial Mass Planets in and Around the Habitable Zones of Single Planet Systems.  NAI Workshop ``Revisiting the Habitable Zone,’'.  Seattle, WA.
  • Kopparapu, R. & Barnes, R.  (2010).  Dynamical Stability of Terrestrial Mass Planets in and around the Habitable Zones of Single Planet Systems.  Am. Astron. Soc. Meeting \# 215.  Washington, DC.
  • Kress, A.P.M.  (2010).  “Modeling the entry of micrometeoroids into the atmospheres of Earth-like planets”.  Meteoroids 2010.  Breckenridge, CO.
  • Kress, M.T.M.E.  (2010).  “A numerical study of micrometeoroids entering Titan’s atmosphere”.  Meteoroids 2010.  Breckenridge, CO.
  • Kress, R.T.C.P.S.J.M.E.  (2010).  “Constraining the drag coefficients of meteors in dark flight”.  Meteoroids 2010.  Breckenridge, CO.
  • Kundurthy, P.  (2010).  Results From The APO Survey Of Transit Lightcurves of Exoplanets (APOSTLE).  Am. Astron. Soc. Meeting # 215.  Washington, DC.
  • Lee, B.W.  (2010).  TYC 1240-945-1b: First Brown Dwarf Candidate from the SDSS-III-MARVELS Planet Search.  Am. Astron. Soc. Meeting # 215.  Washington, DC.
  • Light, B., Brandt, R.E. & Warren, S.G.  (2009).  Hydrohalite in cold sea ice: Laboratory observations of single crystals, surface accumulations, and migration rates under a temperature gradient, with application to “Snowball Earth.”.
  • Lyons, J.R.  (2009).  Evaluating SO2 photolysis as the source of Archean sulfur MIF.  Geochimica Et Cosmochimica Acta, 73(13): A807-A807.
  • McArthur, B., Benedict, G., Barnes, R., Martioli, E., Korzennik, S., Nelan, E. & Butler, R.P.  (2010).  New Observational Constraints on the $\upsilon$ Andromedae System with Data from the Hubble Space Telescope and Hobby Eberly Telescope.  Am. Astron. Soc. Meeting # 216.  Miami, FL.
  • Meadows, V.S. & Seager, S.  (2010).  Terrestrial Planet Atmospheres and Biosignatures.  In: Seager, S. (Eds.).  Exoplanets.  University of Arizona Press.
  • Mielke, S., Dong, M., Kiang, N. & Gunner, M.  (In Press).  Midpoint redox potentials of PSII cofactors in the cyanobacterium, Acaryochloris marina, calculated by multi-conformation continuum electrostatics (MCCE).
  • Mielke, S., Kiang, N., Blankenship, R. & Mauzerall, D.  (2010).  “Thermal Efficiency of Photosynthesis in the Cyanobacterium, Acaryochloris marina,” – Oral Presentation and Poster.  Eastern Regional Photosynthesis Conference.  Marine Biological Laboratory, Woods Hole, MA.
  • Mielke, S., Kiang, N., Chen, M., Blankenship., R.E. & Mauzerall, D.  (In Press).  Thermal efficiency of photosynthesis in the cyanobacterium, Acaryochloris marina.
  • Mielke, S., Kiang, N., Gunner, M., Blankenship, R. & Mauzerall, D.  (2009).  “Photosynthetic Electron-Transfer in the Cyanobacterium, Acaryochloris marina,” – Oral Presentation.  NAI Executive Council Meeting.  Yellowstone National Park, Wyoming.
  • Mielke, S., Mauzerall, D., Blankenship, R.E. & Kiang, N.Y.  (2010).  Constraining photosynthetic biosignatures: Spectral photoacoustic measurements of photon energy use efficiency in the far-red/near-infrared by the chlorophyll d-utilizing cyanobacterium Acarychloris marina.  International Photosynthesis Congress 2010.  Beijing, China.
  • Mielke, S., Mauzerall, D., Blankenship, R.E. & N.Y., K.  (2010).  Constraining photosynthetic biosignatures: Spectral photoacoustic measurements of photon energy use efficiency in the far-red/near-infrared by the chlorophyll d-utilizing cyanobacterium Acarychloris marina.  Revisiting the Habitable Zone Workshop.  Talaris Conference Center, Seattle, WA.
  • Mielke, S.K.N., Blankenship, R., Gunner, M. & Mauzerall, D.  (2010).  “Photosynthetic Electron-Transfer in the Cyanobacterium, Acaryochloris marina,” – Poster and Lightning Talk.  Astrobiology Science Conference 2010.  League City, Texas.
  • Mielke, S.P., Kiang, N.Y., Blankenship, R.E. & D., M.  (2010).  Thermal Efficiency of Photosynthesis in the Cyanobacterium, Acaryochloris marina.  Eastern Regional Photosynthesis Conference.  Marine Biological Laboratory, Woods Hole, MA.
  • Mielke, S.P., Kiang, N.Y., Blankenship, R.E., Gunner, M.R. & Mauzerall, D.  (2010).  Photosynthetic Electron-Transfer in the Cyanobacterium, Acaryochloris marina.  Astrobiology Science Conference 2010 – Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond.  League City, Texas.
  • Mielke, S.P., Kiang, N.Y., Gunner, M.R., Blankenship, R.E. & Mauzerall, D.  (2009).  Photosynthetic Electron Transfer in the Cyanobacterium, Acaryochloris marina.  NAI Executive Council Meeting.  Yellowstone National Park, Wyoming.
  • Mullins, K. & Barnes, R.  (2009).  Tidal Timelines: Evolution of Terrestrial Exoplanet Habitability Around Low Mass Stars.  Am. Geophys. U.  San Francisco, CA.
  • Mullins, K. & Barnes, R.  (2010).  Tidal Timelines: Evolution of Terrestrial Exoplanet Habitability Around Low Mass Stars.  NAI Workshop ``Revisiting the Habitable Zone,’'.  Seattle, WA.
  • O’Brien, D.P., Walsh, K.J., Morbidelli, A., Raymond, S.N., Mandell, A.M. & Bond, J.C.  (2009).  Early Giant Planet Migration in the Solar System: Geochemical and Cosmochemical Implications for Terrestrial Planet Formation.  American Astronomical Society.
  • Pevyhouse, A.  (2010).  THE MICROMETEORITIC CONTRIBUTION OF VOLATILE ORGANICS TO THE ATMOSPHERES OF THE CURRENT EARTH AND PLAUSIBLE EARTH LIKE WORLDS.  San Jose State University.
  • Raymond, S., Greenberg, R., Jackson, B., Kaib, N. & Barnes, R.  (2010).  CoRoT-7 b: Super-Earth or Super-Io?  Am. Astron. Soc. Meeting # 215,.  Washington, DC.
  • Robinson, T.D., Meadows, V. & Crisp, D.  (2010).  Earth as an Extrasolar Planet.  American Astronomical Society, DPS meeting #42.
  • Robinson, T.D., Meadows, V.S. & Crisp, D.  (2010).  Detecting Oceans on Extrasolar Planets.  Astrobiology Science Conference 2010: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond.  League City, Texas.
  • Robinson, T.D., Meadows, V.S., Deming, D., A’Hearn, M.F., Charbonneau, D., Hewagama, T., Lisse, C., Livengood, T., McFadden, L., Seager, S., Wellnitz, D.D. & Team, E.E.  (2010).  Earth as an Extrasolar Planet: The VPL Earth Model Validated Against EPOXI Observations.  American Astronomical Society, DPS meeting #41.
  • Seifert, J. & Souza, V.  (2010).  Symposium and press conference in Saltillo, Mexico on September 22, 2010, with Valeria Souza to discuss the research and preservation work of Cuatro Cienegas.
  • Shields, A.L., Meadows, V.S., Robinson, T.D., Deming, L.D., A’Hearn, M.F., Charbonneau, D., Hewagama, T., Lisse, C., Livengood, T., McFadden, L., Seager, S., Welnitz, D.D. & Team, E.E.  (2010).  Earth as an Extrasolar Planet: Comparing Polar and Equatorial Views.  Astrobiology Science Conference 2010.  League City, TX.
  • Som, S., Anderson, R., Antonio, M., Cash, M., Claire, M., Cowan, N., Ewert, M., Goldman, A., Snowden, D. & Stueeken, E.  (2009).  The 2009 Astrobiology Graduate Student Conference (AbGradCon). Abstract #511.  Astrobiology Science Conference.  League City, TX,.
  • Som, S., Domagal-Goldman, S., Wright, K., Boldt, M. & Antonio, M.  (2009).  THE ASTROBIOLOGY GRADUATE STUDENT CONFERENCE (ABGRADCON).  60th International Astronautical Congress.  Daejeon, South Korea.
  • Souza, V., Breitbart, M., Hollander, D., Elser, J., Meadows, V. & Siefert, J.  (2010).  Cuatro Ciénegas, a Desert Oasis with Active Stromatolites: An Astrobiological Project.
  • Sparks, W.B., Meadows, V., McCullough, P., Postman, M., Bussey, B. & Christian, C.  (2010).  Lunar Based Observations of the Earth as a Planet.
  • Spiegel, D.S., Raymond, S., Dressing, C.D., Scharf, C.A., Mitchell, J.L. & Menou, K.  (2009).  General Milankovitch Cycles.  Pathways Towards Habitable Planets.  San Francisco: Astronomical Society of the Pacific.
  • Stüeken, E.E., Foriel, J., K.Nelson, B. & R.Buick.  (2010).  Selenium Biogeochemistry as a Planetary Deep-Time Redox Proxy.
  • Tian, F.  (2010).  Atmospheric Stability of Earth-like planets in the Habitable Zones of M-stars.
  • Tian, F.  (2010).  Planetary Atmosphere Stability in the Habitable Zones of M-stars.  Pasadena, CA.  American Astronomical Society, DPS meeting #42.
  • Walsh, K.J., Morbidelli, A., Raymond, S.N., O’Brien, D.P. & Mandell, A.M.  Origin of the Asteroid Belt and Mars’ Small Mass.  American Astronomical Society, DPS meeting #42.
  • Williams, D.M. & Zugger, M.  (2010).  Polarization Of Starlight By Exoplanets With Watery Surfaces.  American Astronomical Society, AAS Meeting #215.
  • Zahnle, K., Catling, D. & Claire, M.  (2009).  Does Microbial Zonation Recapitulate Phylogeny? A Possible Role for Biogenic Sulphur Gases in the Transition from Methane to Free Oxygen.  AGU Fall Meeting.  San Fransisco, CA.
  • Zahnle, K., Catling, D. & Claire, M.  (2009).  ``Does Microbial Zonation Recapitulate Phylogeny? A Possible Role for Biogenic Sulphur Gases in the Transition from Methane to Free Oxygen.”.  AGU Fall Meeting.  San Francisco, CA.
  • Zahnle, K., Claire, M. & Wing, B.  (2010).  Biogenic Sulfur Gases, MIF-S, and the Rise of Free Oxygen.  Goldschmidt 2010.
  • Zahnle, K., Claire, M. & Wing, B.  (2010).  Biogenic Sulfur Gases, MIF-S, and the Rise of Free Oxygen.  Goldschmidt.  Knoxville, TN.
  • Zugger, M., Williams, D.M. & Kasting, J.F.  (2010).  Polarization of Starlight by Exoplanet Oceans.  Astrobiology Science Conference 2010.  League City, Texas.
  • Zugger, M.E., Kasting, J.F., Williams, D.M., Kane, T.J. & Philbrick, C.R.  (In Press).  Simulated light curves from ocean and Lambertian exoplanets with Rayleigh-scattering atmospheres.  Ap Journal.