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| Paper: |
Towards a Remote Sensing Capability for Life's Chiral Signature |
| Volume: |
449, Astronomical Polarimetry 2008: Science from Small to Large Telescopes |
| Page: |
396 |
| Authors: |
Sparks, W. B.; Germer, T.; Hough, J. H.; Manset, N.; Chen, F.; DasSarma, S.; DasSarma, P.; Robb, F.; Kolokolova, L.; Reid, I. N. |
| Abstract: |
A unique characteristic of life is the homochirality of biological
molecules. This offers the potential for developing a remote sensing
diagnostic since chiral signatures can be revealed on a macroscopic
scale with circular polarization. We are quantifying the circular
polarization signal produced by astrobiologically relevant
microorganisms and comparing the results to macroscopic vegetation (such
as leaves) and abiotic minerals. Our aim is to understand whether
circular polarization offers a viable technique for detection of life
signatures and hence will be useful as an element of telescopic searches
for life elsewhere in the Universe. By concentrating on photosynthesis,
we maximize observability from an astronomical perspective, since
photosynthesis and phototrophy is typically a surface phenomenon
requiring atmospheric transparency and high stellar flux. We also
maximize the likely polarization signal since circular dichroism is
greatest in the strong electronic transitions that define photosynthetic
absorption bands. We show that signatures of life's chirality are
present in the polarization spectra of the biological samples and hence
circular polarization can be a powerful biomarker. It can be used
remotely and exploits a generic and unique characteristic of biochemical
life, its homochirality. |
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