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2006 Annual Science Report

University of Arizona Reporting  |  JUL 2005 – JUN 2006

Executive Summary

The past year has seen a number of activities coming to fruition. First, for module 1 (the Building Blocks of Life) the major construction item in our budget, the Microwave Fourier Transform Spectrometer for determination of mm wave spectra of complex organic molecules is complete and working. Measurements have been made of acetol and lactonitrile. Associated with this, surveys for molecules in a dense molecular cloud have shown the absence of dihydroxyacetone, hydroxyacetone, lactonitrile, lactic acid, formyl cyanide, and methylene cyclopropene at the confusion limit. On the other hand, glycoaldehyde and acetamide are definitely present, and acetamide explains a number of formerly unidentified lines. There has been a survey of formamide in dense clouds. Observations of CCH in planetary nebulae showed that some C-C bonds survive the strong UV radiation in this phase. We have also explored formaldehyde’s origin in comets. Over 1000 hours of observation with ARO telescopes were made this year. Dr. Dante Lauretta of LPL has joined the group, so that we can link meteorite studies and Earth biochemistry issues to the chemistry of space. In addition we have just added Dr. Matt Pasek as Bessey Postdoctoral Fellow studying the acquisition of phosphorus by pre-biotic organic molecules.

Module 2 (Formation of a Habitable World) has made progress on the early history of planetary systems, on the issue of whether gas remains after dust disks have vanished. Mid IR spectroscopy with the Spitzer Space Telescope has been combined with mm-wave observations of CO to show that in systems at 30 M.y. age less than 10Mearth of gas remains. Giant planets must accrete rapidly, and terrestrial planet orbits must circularize early. Yet despite these indications of early loss of disks, debris disks have been discovered around sun-like Pleiades stars 100 M.y. old. In a collaboration between module 2 and module 3, ground telescopic observations in the 1-25 micron range are being made at the MMT. These have ranged from looking for cool companions with Speckle Differential Imaging (SDI) to searches for even cooler companions in the 5 micron window of reduced opacity, and searches for debris disks in the thermal IR.

Our program to monitor the variability of luminosity and magnetic activity of stars of assorted ages is now fully operational. We have completed the construction of our camera for photometric monitoring of stars in open clusters. Early observations have been made of Pleiades, and we are ready to start observations of M67. This program is being combined with spectroscopic observations of the same stars with the WIYN and MMT telescopes.

Module 3 (the Nature of Planetary Systems) has pursued new techniques to observe fainter and closer companions to stars. Studies of stars with the 3-5 micron camera and MMT adaptive secondary mirror have allowed searches for planetary companions to significantly fainter limits than other telescopes. In a new technical development funded by LAPLACE, we have manufactured a pupil plane phase mask designed by John Codona with Roger Angel. This mask removes the diffracted light from one side of the image, and at 5 microns wavelength allows observations with the MMT to as close as 0.4 arc seconds. We have now reached a limit close to the star set by the delay in adaptive optics keeping up with the seeing screen moving across the telescope aperture. This limit will allow detection of planets at the close limit at least 11 magnitudes fainter than the star at 5 microns. Theoretical modelling of giant planet spectral emission has continued and a comprehensive invited review has been published in Nature.

A near IR (1.65 micron) survey using SDI techniques is continuing in both hemispheres. An observation of a companion to AB Dor indicates a need to modify the low mass star relationship between mass luminosity and age at young ages. Also it has resulted in the detection of a brown dwarf at 3.9 pc which makes it one of the closest stars to the sun.

Our first astrobiology tenure track faculty member is working with module 3. Dr. Alex Pavlov of LPL is studying the early atmosphere of Earth, and effects on the temperature of Earth. This has particular application to the Terrestrial Planet Finder mission.

In addition to this work, members of LAPLACE have been involved in a Discovery Mission proposal, TOPS (Telescope to Observe Planetary Systems) in collaboration with NASA Ames Research Center. Roger Angel, Adam Burrows, Michael Meyer, Tim Slater and Neville Woolf are all Co-Investigators. Olivier Guyon is the P.I. and a further 3 members from UAz are Co-I’s, 2 are collaborators and 5 are key personnel. In addition, members of the Penn. State, NASA Ames and VPL teams of NAI are also

Module 4 (Strengthening the Astrobiology Community) has had a very active year. We had a second activity jointly with the U. Washington team, with astronomy graduate students visiting Puget Sound to study the biota of the Cambrian Revolution. Then in January we held a Winter School with 29 students, including 7 international students, both observing at radio and optical wavelengths and including solar observations at Kitt Peak, and visiting labs and having lectures and demonstrations in Tucson. A graduate course in Astrobiology was taught in the spring, and there is a continuing weekly journal club in Astrobiology discussing topics of current interest. LAPLACE funds supported bringing in a number of outside speakers for these meetings.

LAPLACE has joined with the College of Science at the University of Arizona to present sets of talks on issues of public interest. The first 7 lectures were about evolution, and overflowed its original auditorium, typically ending with over 600 attendees per talk. In the fall this identical lecture series will be given in Phoenix. Also this fall a lecture series on global climate change will be given. Also the Templeton lectures on Astrobiology and the Sacred were given this spring. These included 10 science talks including 2 from LAPLACE faculty. In connection with both of these lecture series, our EPO group taught courses for middle school and high school teachers.