nai

Project Progress

Module 1: The Building Blocks of Life

This module is concerned with examining the contribution of interstellar chemistry to the biochemistry that led to living systems on Earth. The focus of this investigation is the simple sugar ribose and its precursors, starting with formaldehyde. This module is attempting to accurately establish the presence of simple sugars and their precursors in interstellar gas, examine possible gas-phase mechanisms leading to such sugars, and investigate how such precursors might have found their way to a planet surface. This module therefore combines high resolution laboratory spectroscopy, radio astronomy of interstellar molecules, synthetic organic chemistry in the gas-phase, theoretical calculations of reaction pathways, comet studies, and investigations of carbon isotope ratios.

This module addresses:

• Goal 3 of the Astrobiology Roadmap, Understand how life originates from cosmic and planetary precursors, Objectives 3.1 (sources of prebiotic materials) and 3.2 (origins and evolution of functional biomolecules), and
• Goal 4 of the Astrobiology Roadmap, Understand how past life on Earth interacted with its changing planetary and Solar System environment, Objective 4.3 (effects of extraterrestrial events upon the Biosphere).

Highlighted Accomplishments

• Completed construction of a pulsed molecular-beam Fourier transform microwave spectrometer.
• Measured the microwave and millimeter spectrum of the lowest energy conformer of acetol.
• Conducted survey of molecular cloud Sgr B2(N), covering about half of the 2 and 3 mm (70 — 170 GHz) spectrum; absolutely confirmed the identification of the interstellar molecules glycolaldehyde, vinyl alcohol and ethylene glycol; tentative detections of propenal and propanal have been made.
• Calculations performed on conformational behavior of sugars (ribose), showing the multitude of structural isomers of these systems that differ little in terms of their stability.
• Observations of comets, Q4/NEAT and T7/LINEAR; detected H₂CO towards both these comets at 1mm.
• Completed study of ¹²C/¹³C ratios using the N=1_0 transition of CN; results are in reasonable agreement with previous ratios established independently from CO and H₂CO, suggesting that chemical fractionation is not important.
• Expanded collaborations within the University of Arizona between the astronomy and chemistry departments.
• Performed 700 hours of observations using the Arizona Radio Observatory’s 12-meter telescope at Kitt Peak, Arizona.

Laboratory Spectroscopy

In order to examine which molecular species are present in interstellar clouds, the pure rotational spectra of such compounds must be well-known. Because the molecules of interest are relatively heavy species with complicated spectra at room temperature, Staff Scientist Aldo Apponi constructed of a pulsed molecular-beam Fourier transform microwave spectrometer in order to study these species. The supersonic jet nozzle, which is the source of molecular gas for this system, enables the species of interest to be cooled to low rotational temperatures, greatly simplifying a complex spectrum. This spectrometer is now complete and fully functional through our phase 1 goals of 3.5-18.5 GHz, and its sensitivity is within a factor of five of the design specifications. This spectrometer, used in conjunction with any of three direct absorption millimeter wave spectrometers of the Ziurys lab, has for the first time enabled us to characterized the complex gas phase spectra of prebiotic sugars, their derivatives and other prebiotic molecular precursors.

The first program in this study is the 3-carbon sugar hydroxyacetone. Hydroxyacetone, or acetol, is the simplest ketose. Identification of this sugar in interstellar environments will provide important clues on the chemical processes that form simple sugars. The well known interstellar sugar glycolaldehyde is thought to form via the condensation of formaldehyde- a process that is still not well understood. Hydroxyacetone, on the other hand, must form through a completely different mechanism. The contrast between these two mechanisms will place constraints on the models of interstellar organic chemistry.

The microwave spectrum of acetol was first studies by Kattija-Ari and Harmony (1980, International Journal of Quantum Chemistry, 14, 443). Unfortunately, their dataset was not large enough to accurately predict any lines in the millimeter wave region. With our new microwave spectrometer, we have already doubled the microwave data set, a sample spectrum is shown in Figure 1. The constraints provided by these new measurements have enabled us to begin assigning the millimeter wave spectrum of acetol. So far, we have covered the full 3mm wave spectrum- the frequencies most relevant to an astrophysical search for this molecule- and we will begin searching for it in Sgr B2(N) in the Fall of 2005 using the ARO 12 meter telescope.

{{ 1 }}

Radioastronomy Searches for Prebiotic Molecules

Over the past two years, Apponi, Halfen, and Ziurys have begun an intensive interstellar survey towards the famous Sgr B2(N) molecular cloud near the Galactic center. This source harbors the most complex organic molecules, many of which have biologically important functional groups, i.e. aldehydes, acids, sugars, etc. Identification of molecules in the interstellar gas is vital for understanding the processes that occur in the condensed phase. For instance, much of the material found on the meteorites is closely related to the abundant molecules found in the interstellar gas, e.g. hydroxyl acids are related to aldehydes and hydrogen cyanide, amino acids are related to aldehydes, hydrogen cyanide and ammonia.

The millimeter wave spectrum of Sgr B2(N) is quite complicated, and has proven difficult to elucidate. For instance, two recently claimed detections, glycine and dihydroxyacetone, have subsequently been proven false. The only way to fully characterize these spectra is through highly sensitive surveys over the entire region where these molecules emit. We have thus far covered about half of the 2 and 3 mm (70 — 170 GHz) spectrum of Sgr B2(N) and will complete the survey over the next 2 years. Additionally, a 1 mm survey (210 — 270 GHz) is also planned to start in the Fall 2005 using the ARO 10 meter telescope. Thus far, we have absolutely confirmed the identification of the interstellar molecules glycolaldehyde, vinyl alcohol and ethylene glycol; tentative detections of propenal and propanal have been made (see Figure 2). On the other hand, we see no evidence for dihydroxyacetone, glycine, propynal, or vinyl isocyanide. The results from this survey will greatly constrain the interstellar processes governing the production of prebiotic molecules.

{{ 2 }}

Gas-Phase Synthetic Organic Chemistry

The prebiotic source of ribose is thought to be the so-called formose reaction, which leads from formaldehyde (H₂C=O) to glycolaldehyde or diose (HOCH₂CH=O), and eventually ribose (CH₂O)₅. A detailed aldol mechanism for the formose reaction sequence from the two-carbon diose onwards to the five-carbon ribose was proposed by Breslow (Tetr. Lett. 21, 22, 1959). However, the mechanistic details of the first, and most crucial carbon-carbon bond-forming step from formaldehyde to diose remain murky.

In January, 2005 research scientist Leif Abrell started to examine acid-catalyzed, gas phase variants of the formose reaction using a drift tube instrument at 2.0 mbar. Formaldehyde gas in an argon stream was generated from paraformaldehyde. With access to a proton transfer reaction-mass spectrometer (PTR-MS) instrument, gaseous H₃O was generated, and H was transferred to formaldehyde (CH₂=O) in a drift tube (reaction chamber) at 2.0 mbar and 70°C. Collision reaction products with higher (CH₂O)_n masses at 60, 90, and 120 amu were observed by quadrupole detection downstream from the PTR-MS drift tube. Multiple isobaric compounds with masses 60, 90, and 120 amu are possible, but could not be distinguished by the quadrupole mass spectrometry measurements. For example, quadrupole detection of protonated ion m/z = 61 may correspond to the following isobaric compounds with molecular formula C₂H₅O₂: acetic acid (CH₃COOH₂), methyl formate (CH₃OCH=OH), or the formaldehyde dimmer (H₂C=O-H-O=CH₂), in addition to diose (HOCH₂CH=O-H⁺).

Structural information in the form of fragmentation patterns to distinguish between isobaric compounds with protonated masses 61, 91, and 121 amu will be used to identify possible formose reaction species. Preliminary results using the atmospheric pressure chemical ionization tandem mass spectrometry (APCI-MS/MS) in the Proteomics Core Facility at the UA College of Pharmacy indicated weak ionization. New sample conditions for APCI-MS/MS are being evaluated, and new experiments with the same samples in the gas phase are being planned using a direct batch inlet (DBI) method based on chemical ionization of sublimed samples and spectral measurement with a high resolution time-of-flight mass spectrometer (TOFMS) analyzer.

Theoretical Calculations

Work conducted by L. Adamowicz and students has centered on the study of structures and stabilities of some biologically-relevant sugars. Work has also started on mechanistic studies of the sugar formation reactions. The application calculations performed on conformational behavior of sugars (ribose) showed multitude of structural isomers of these systems that differ little in terms of their stability. The stability relations will help identify the most likely mechanism for sugar formation out of simpler systems. The group has started investigation of such mechanisms by performing calculations on the Nazarov-type reaction concerning addition of two aldehydes mediated by a hydronium cation. This is a possible reaction contributing to the process of the gas-phase formation of simple sugars.

Cometary Studies

Comets are considered to be composed of pristine interstellar material from the molecular cloud from which our solar system was originally formed. As a comet orbits the solar system, it becomes significantly close to the sun’s radiation at which point it begins to sublimate, ejecting ancient material into the solar system in the form of small particles and gases. These vaporizing gases trace the conditions of the molecular cloud from which our sun was formed 4.6 Gyr ago. Radioastronomy provides a mechanism by which cometary gases can be analyzed.

Two new comets appeared during 2004: Q4/NEAT and T7/LINEAR. Using the ARO 12-meter telescope, H₂CO was detected towards both these comets at 1mm. In the spectra observed towards LINEAR, a second velocity component appears to be present in the data (see Figure 3). This component could arise from thermal degradation of “POM” material that is thought to surround the comet nucleus, while the main component probably comes from direct sublimation of the water-ice matrix of the nucleus. These data are currently being analyzed, and compared with H₂CO spectra obtained from Hale-Bopp. CH₃OH and CH₃CN spectra observed towards comet Hale-Bopp are also being studied. This work is being conducted by S. Milam, L. Ziurys, and S. Wyckoff.

{{ 3 }}

²C/¹³C Isotope Ratios

One of the clear signatures of extra solar origins of material are isotope ratios. That of carbon is particularly important since organic chemistry is the chemistry of life. It is clearly necessary to establish this isotope ratio accurately outside our solar system. During this past year Milam, Ziurys, and Wyckoff have completed their study of ¹²C/¹³C ratios using the N=1_0 transition of CN; observations have been conducted with the ARO 12-m telescope. The results from CN are in reasonable agreement with previous ratios established independently from CO and H₂CO. These molecules all indicate a gradient across the Galaxy, as shown in Figure 4. The remarkable result is the agreement between the ratios obtained from these three molecules, which suggests that chemical fractionation is not important. Therefore, the ¹²C/¹³C ratios obtained are a true indicator of the relative amounts of ¹²C and ¹³C. Ratios obtained from organic compounds in meteorites and IDP’s can be compared to interstellar values with some certainty and therefore be used to trace the origins of these materials.

{{ 4 }}

Module 2: Formation and Evolution of Habitable Worlds

This module aims to use observations of the gas and dust in (a) planet-forming accretion disks surrounding young stars; and (b) debris disks surrounding more mature stars to understand key steps and timescales in the formation of planetary systems and their evolution, and to constrain outcome planetary system architectures. Another objective of the module is to provide candidate targets for direct detection and characterization of planets.

This module addresses:

• Goal 1 of the Astrobiology Roadmap, Understand the nature and distribution of habitable environments in the Universe.

Highlighted Accomplishments

• Detection of abundant gas lying within apparent opacity holes — perhaps indicating an absence of small (r < 1 micron) grains in inner disks.
• Results from the Spitzer Space Telescope continue to inform our research program within Module 2 concerning the evolution of inner dust disks, search for warm debris disks analogous to our solar system’s asteroid belt, constraints on remnant molecular gas in debris disks, and the frequency of cold outer debris disks.
• Najita and Williams’ results from the 850 micron JCMT/SCUBA survey suggest that the mass in small grains declines significantly on a ~200 Myr timescale.

Gas Content of Disks

Understanding the evolution of the gas in disks can provide insight into the processes of giant and terrestrial planet formation. In the context of giant planet formation, both total disk masses (which are dominated by the gaseous component) and the lifetime of gas in the giant planet region of the disk can be used to constrain the dominant mode(s) of giant planet formation.

The lifetime of gas in the terrestrial planet region of the disk is also of interest. This is because residual gas in this region of the disk can affect the outcome of terrestrial planet formation, i.e., the masses and eccentricities of planets, their speed of formation, and their consequent habitability. Only a narrow range of gas column densities is expected to produce terrestrial planets with the Earth-like masses and low eccentricities that we associate with habitability on Earth.

These considerations motivate the characterization of the gaseous component of disks
over a range of radii, in both the giant and terrestrial planet regions of the disk (1— 20 AU) and over a range of masses, from the large gas masses characteristic of giant planet formation (1M_J) down to the residual gas masses of interest for the outcome of terrestrial planet formation. The availability of sensitive near- and mid- IR high resolution spectrographs on 8-10m class telescopes provides a powerful tool for probing the gas content of disks and the radial distribution of gas within disks complementary to surveys for gas with the Spitzer Space Telescope and ground-based sub-mm facilities.

Module 2 members Najita and Chen have continued to carry out studies aimed at constraining the gas content and radial distribution of gas around solar-like and intermediate mass stars. In collaboration with Glassgold and Igea, Najita calculated the thermal-chemical structure of the gaseous atmospheres of the inner disks of accreting solar-like pre-main sequence stars, taking into account processes such as X-ray irradiation or mechanical heating of the surface layers, and calculating the vertical gas temperature structure in the neighborhood of 1 AU. These calculations are then used to predict the relative column densities of key molecular tracers used to characterize the gas content of PMS star disks (Glassgold, A., Najita, J. and Igea, I. 2004, ApJ 615, 972) — a key first step toward deriving gas masses from observations of tracers such as CO.

As part of the FEPS project, Hollenbach et al. (2005, ApJ in press) report infrared spectroscopic observations with the Spitzer IRS of HD 105, a nearby (d ~ 40 pc) and relatively young (t ~ 30Myr) G0 star with excess infrared continuum emission, which has been modeled as arising from an optically thin circumstellar dust disk with an inner hole of size r ~13 AU. The observations provide upper limits to the fluxes of H₂ S(0) 28µm, H₂ S(1) 17µm, H₂ S(2) 12 µm, [FeII] 26µm, [SiII] 35µm, and [SI] 25µm infrared emission lines. These authors compare the line flux upper limits to predictions from detailed thermal/chemical models for several assumed gas distributions in the disk and conclude that the gas content must be considerably below the value for a minimum mass solar nebula. Therefore, it is unlikely that there is sufficient gas for gas giant planet formation to occur in HD 105 at an age of 30 Myr.

Najita continued her studies (in collaboration with John Carr) of CO emission arising from circumstellar accretion disks surrounding classical T Tauri stars and a subset of classical TTS, so-called ‘transition disks’ which have exhibit spectral energy distributions suggestive of inner opacity holes extending from near the stellar surface to distances of several astronomical units. Of particular interest is the detection of apparently abundant gas clearly lying within the apparent opacity hole — perhaps indicating an absence of small (r < 1 micron) grains in the inner disk. Najita and collaborators are pursuing a variety of diagnostic observations aimed at understanding whether transition objects require the formation of planetary mass bodies both within the inner hole, and at the outer edge of the hole.

Chen is initiating studies of the gas content among a group of stars in the 5-10 Myr old Sco-Cen association whose spectral energy distributions suggest the presence of inner disk holes. These observations aim to place robust upper limits on accretion rates, and to attempt direct detection of gas in the inner disk regions.

Dust Content of Disks

Results from the Spitzer Space Telescope continue to inform our research program within Module 2. Recent highlights from the Spitzer Legacy Science Program entitled
Formation and Evolution of Planetary Systems (http://feps.as.arizona.edu)
include:

1. constraints on inner (R < 0.1 AU) disk lifetimes from a 3-8 micron survey of over 70 stars with ages from 3-30 Myr (Silverstone et al. 2005);
2. discovery of an unusual debris ring surrounding the star HD 12039 (Hines et al. 2005);
3. census of cold outer debris disks (R > 30 AU) surrounding sun-like stars (Kim et al. 2005); and
4. constraints on debris disk evolution in the 100 Myr old Pleiades open cluster (Stauffer et al. 2005). Additional studies undertaken by members of the MIPS Instrument Team as well as NASA grant LAPLACE Team Members Chen and Najita (Watson et al. 2005; Chen et al. 2005) complement this work.

The NAI grant to Arizona provides support for ground-based telescopic observations crucial to following-up this work. Research Associate Daniel Apai is leading efforts to:

1. resolve mid-infrared emission from debris disks surrounding FEPS targets using the techniques of direct imaging and nulling interferometry with the 6.5m MMT telescope as well as the Gemini Observatory; and
2. detect directly gas giant planets hypothesized to surround FEPS targets with debris disks that sport large inner holes in their dust distributions. Additional work focusing on whether brown dwarf objects, failed stars with masses less than that required to sustain energy-producing nuclear reactions in their interiors, form with circumstellar disks from which planets might form (Apai et al. 2005).

Models of Dust Evolution

Taking advantage of the interdisciplinary nature of research conducted within LAPLACE, team members Hinz, Kring, Malhotra, and Meyer are working to build models of solar system evolution that can be compared to observations of ensembles of sun-like stars in the disk of the Milky Way. For example, in a recent paper, Strom, Malhotra, Ito, and Kring (2005) argue that the late-heavy bombardment in the inner solar system was due in part to an influx of asteroids created through migration of the giant planets. Such an event would have profound implications for predicted dust generation rates in debris disks observed. In Figure 5, we compare a toy model for the evolution of our solar system to recent observations of debris disks surrounding sun-like stars as a function of age, as well as current observational limits and predictions for new capabilities under development.

{{ 5 }}

Finally, for his senior honors thesis, undergraduate student Praveen Kundurthy completed a study of the dependence of stellar rotation on the presence or absence of a disk from 0.1-1.0 AU traced by near- and mid-infrared excess emission. He presented this work at the NAI 2005 meeting in Boulder, CO and a final manuscript in being readied for submission to the PASP.

Workshops for Module 2

Module 2 members have instituted a series of all day workshops that cover aspects of planet formation including reviews of recent results from space- and ground-based observations, as well as advances in theory. In February, 2004, well-known planet formation theorist Professor D.N.C Lin visited LAPLACE from the University of California, Santa Cruz and participated in one of these workshops during an extended visit to the Tucson area.

Module 3: Nature of Planetary Systems

Direct detection for extrasolar planets is fast becoming a reality, and LAPLACE is well-poised to be in the forefront of this new area of research. Using multiple techniques researchers in this module are now in the process of carrying out surveys for young planets as well as developing new techniques which will push our sensitivity to older planets around more nearby stars. Module 3 work has developed new instrumentation to detect these planets, begun surveys using existing adaptive optics techniques and furthered modeling work to enable the interpretation of detections from a range of observatories, including, the Hubble Space Telescope (HST), Spitzer Space Telescope, and the James Web Space Telescope (JWST). This work is laying the foundation for understanding what other stellar systems may be hospitable to life and how we identify such systems.

This module addresses:

• Goal 1 of the Astrobiology Roadmap, Understand the nature and distribution of habitable environments in the Universe, objectives 1.1 (models of formation and evolution of habitable worlds) and 1.2 (indirect and direct astronomical observations of extrasolar habitable planets.

Highlighted Accomplishments

• Discovery of close companion to AB Dor using Simultaneous Differential Imaging.
• Determination that current theoretical models overestimate the brightness of substellar objects at young ages.
• Creation of self consistent models for the light curves and phase functions of giant planets at a broad range of orbital separations.
• Improved sensitivity of MMT adaptive optics system allows detection of planets of significantly smaller masses than other systems.
• Completion of comprehensive invited review for Nature by Adam Burrows that provides the best theoretical guide for the search for planets outside the Solar System.

Ongoing Near-Infrared Survey

Laird Close is leading an adaptive optics survey at H (1.65 micrometers) band to look for young companions using both the 8.2-meter Very Large Telescope (VLT) in the southern hemisphere and the 6.5-m MMT in the northern hemisphere. Graduate student Eric Nielsen is carrying out the survey. Their approach uses the technique of Simultaneous Differential Imaging (SDI) in and out of methane to enhance sensitivity to giant planets in the presence of scattered light of the parent star.

One of the significant early results from this survey is the discovery of a close companion to AB Dor (Close et al. 2005). Dynamical determination of the mass, combined with the brightness measurement at H band indicates that current theoretical models overestimate the brightness of substellar objects at young ages. Calibration of these models is important for understanding the sensitivity to giant planets of the ongoing surveys.

{{ 6 }}

Adaptive Optics Development

The MMT Adaptive Optics (MMTAO) system is the only such system integrated into the telescope itself. This allows a uniquely smooth point spread function and much lower background in the infrared. Both of these increase the system’s sensitivity for extrasolar planets.

Work this past year has focused on developing techniques of improving the correction of the adaptive optics system. Currently we only correct for aberrations which manifest themselves on spatial scales larger than ~1 meter. By improving calibration of our system we expect to be able to correct for aberrations down to size scales of approximately 0.5 m. Progress in this area is summarized in Brusa et al. (2004) and Kenworthy et al. (2004).

{{ 7 }}

3-5 micron Camera Development

The unique sensitivity of the MMT AO system has been demonstrated this past year using a newly developed 3-5 micron imager (see Freed et al. 2004), called Clio. Phil Hinz has lead this effort. An early result suggests that we can detect giant planets down to nearly 5 Jupiter masses around the nearby star Vega (Hinz et al. 2005, in prep.). Figure 2 shows the expected contrast ratio achievable with the MMT AO system and Clio. Comparison to AO systems working at shorter wavelengths on Keck and Palomar telescopes suggests that the system is sensitive to planets of significantly lower mass.

{{ 8 }}

Modeling Work

Lead by Adam Burrows, work on planet modeling this past year has focused on how planets detected by transits compare to existing models (cf. Burrows, Hubeny, and Sudarsky, 2005 and Burrows et al. 2004), as well as creating self consistent models have for the light curves and phase functions of giant planets at a broad range of orbital separations (Sudarsky et al. 2005).

Adam Burrows contributed a comprehensive invited review to Nature, entitled “A theoretical look at the direct detection of giant planets outside the Solar System”. The paper lays out the most attractive spectral regions and techniques for detection based on the theoretical modeling. This work is currently our best guide to aid ongoing searches.

Module 4: Winter School Institute

LAPLACE has modified the original proposal’s plan to conduct a semester long winter school. Instead we have implemented more innovative approaches to training the next generation of astrobiologists. In the last year’s annual report, we discussed the initiation of a Graduate Student Conference. This year LAPLACE worked with another NAI team, the University of Washington, to initiate an exchange of students between the two institutions to participate in hands-on work in a subdiscipline different from their area of expertise. Additionally Nick Woolf and Michael Meyer hosted a Journal Club for graduate students focusing on astrobiology. LAPLACE also participates in the Templeton Lecture Series: Astronomy and the Sacred.

Highlighted Accomplishments

• LAPLACE hosted students from the University of Washington and non-astronomy departments of the University of Arizona for a five-day hands-on observing course on UA campus and at Kitt Peak National Observatory.
• Development of materials and establishment of format for effective teaching across disciplines in astrobiology.
• Completion of a semester of Astrobiology Journal Club.
• Participation in the Templeton Lecture Series: Astronomy and the Sacred.
• Participation in the Vatican Observatory Summer School.

LAPLACE-UW Exchange — Phase 1

To carry out our goals of educating the next generation of astrobiology researchers, the NAI Arizona (University of Arizona (UA) and National Optical Astronomy Observatory (NOAO)) team is collaborating with the NAI University of Washington (UW) team to hold a hands-on, bilateral exchange program in which students in both teams participate in scientific research at each site. We believe that in order for astrobiologists to make significant and comprehensive discoveries in a specific area of expertise, they must have an appreciation and understanding of the techniques, limitations and power of disciplines other than their own. How effectively this occurs can be problematical. This Exchange brings together Arizona and UW researchers to learn and share information, methods and questions to promote greater appreciation and understanding of what other astrobiologists do and how they do it.

The first phase of this joint activity brought fourteen graduate students from UW and three non-astronomy graduate students from UA to Kitt Peak, Arizona for three days and nights of astronomical observing in March 2005. Arizona faculty and staff, working in close concert with Woody Sullivan of UW, created a curriculum that included hands-on laboratories at five telescopes — three concentrating on optical and infrared night-time observations, one on millimeter wave molecular line observations of interstellar clouds and one on observations of the Sun. The curriculum included information for non-astronomers and ample time for informal discussion and collaboration. Preparatory sessions prior to the March site activities benefited from the use of televideo equipment for meetings as well as postings on web sites.

Work at the telescopes focused on two themes: the Sun as a star through time and the formation of solar-type stars. Despite less-than-optimal weather, the activity was a great success. Members of the Exchange staff were: Daniel Apai, Aldo Apponi, Cathi Duncan, Mark Giampapa, Jonathan Lunine, Michael Meyer, Erika Offerdahl, Tom Olien, William Sherry, Nick Siegler, Paul Smith, Anna Spitz, Woody Sullivan, Nick Woolf%, Lucy Ziurys and telescope scientists, telescope operators, website developers and student workers. Participant exit surveys rated the labs, organization, instruction, logistics, facilities and overall experience. Many students found the discussion sessions among biologists, astronomers and planetary scientists to be some of the most worthwhile times. Most students stated that they learned a great deal from the experience gaining a greater appreciation for their astrobiological colleagues’ fields of research that will enrich their own research.

The second phase of this exchange will be a trip for LAPLACE graduate students and faculty to UW to participate in marine biology research in October, 2005.

The materials developed for this exchange are available online and will be used for future programs. The UA Astronomy Camp modified the radio astronomy portion of the curriculum for use in its summer program for 2005. LAPLACE will use these materials and format (with modifications) to host a Winter School in January 2006.

Astrobiology Journal Club

This year Woolf and Meyer instituted and hosted the Astrobiology Journal Club. This forum provides research and discussion about recent journal articles. In addition, Michael Meyer delivered a series of lectures to and international group of graduate students assembled for the 2005 Kobe International Summer School on Planetary Sciences (http://www.kobe-u.ac.jp/21COEPS/SCHOOL/2005/2005_ischool.html). Students became the primary drivers of the journal articles selected and the discussion forum. The group established a website for distribution and interaction, http://gould.as.arizona.edu/~meyer/grad/astrobio. The Journal Club format proved very effective in extending students’ field of expertise into other areas of interaction. Interactions among researchers with different areas of concentration were most beneficial.

Collaborations

LAPLACE Director, Nick Woolf, and Jonathan Lunine were part of the Vatican Observatory Summer School faculty during the month of June. This program (http://clavius.as.arizona.edu/vo/R1024/VOSS2005.html) targets students from developing nations and funds their four-week study at the Vatican Observatory in Rome. The exchange of ideas about materials, techniques and formatting will be useful in consideration of the Winter School at LAPLACE in 2006.