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Julie E M McGeoch

Center for Astrophysics
Research Associate


Julie McGeoch is a Research Associate at the Center for Astrophysics | Harvard & Smithsonian and before that in FAS Molecular and Cellular Biology. Her research focuses on asteroid derived polymer analysis. Since 2014, in six carbonaceous meteorites (Allende, Acfer-086, Efremovka, Kaba, Orgueil and Sutter's Mill), two fossil stromatolites, and two present day stromatolites, there has been evidence for an abiotic glycine/Fe/O 1494Da polymer. The polymer is likely to form in molecular clouds going on to protoplanetary disks where its light absorption and emittance (IR at 6µm to 480nm) may have a role in accretion. The techniques employed in the research are: detection of the polymer IR absorption by the JWST MIRI (time applied for in Cycle3); mass spectrometry; FIB/SIMS isotope analysis; X-ray diffraction crystallography (at APS and Diamond synchrotrons); infrared absorption via FTIR, and TEM electron diffraction (Diamond and Harvard). The polymer in fossil stromatolites has the same extra-terrestrial isotope enhancement as that in the meteorites, indicating that the polymer component of fossil stromatolites arrived on Earth 2-3 billion years ago via in-fall and could have contributed to the oxygenation of the planet. The polymer has been detected from light absorption and emittance data in the wavelength range 400nm to 6µm and could be in future telescope analysis of protoplanetary disks. The polymer's elements (H, C, N, O) first existed 12.5 billion years ago -- the time point it probably first formed by gas phase polymerization. Time in cycle 3 on the JWST to detect the 6.2micron IR absorption in a molecular cloud has been applied for. The JWST MIRI will be directed at 2 bright stars LHO 102 and LHO 075 to backlight a molecular cloud between the stars and the telescope. Telescopes can tell us about the molecule in its pristine conformation, as opposed to the versions extracted and re-crystallized from meteorites. The detailed shape of the 6.2 micron absorption will tell us how hemoglycin is arranged, whether in extended sheets, or other structures, based upon extensive characterization of such structures in biochemistry. Already via 1998 results from the ISO telescope we can infer that it is in an anti-parallel beta sheet and that several sheets may be in close contact.

Bsc Hons & PhD Southampton University UK