Biosignatures & Paleobiology: April 2007

Multidisciplinary work from members of NAI's SETI Institute Team and a host of collaborators across the NAI re-examines what is known at present about the potential for a terrestrial planet forming within, or migrating into, the classic liquidsurfacewater habitable zone close to an M dwarf star. Their new paper, published in the current issue of Astrobiology, presents the summary conclusions of an interdisciplinary workshop sponsored by NAI and convened at the SETI Institute in 2005. [Source: NAI Newsletter]

Differently colored plants may live on extra-solar planets, according to two new papers in the current issue of Astrobiology authored by members of NAI's Virtual Planetary Laboratory Alumni Team and their colleagues. They took previously simulated planetary atmospheric compositions for Earth-like planets orbiting various star types (including M stars), generated spectra, and found that photosynthetic pigments may peak in absorbance in the blue for some star types, and red-orange and near-infrared for others. Their results also suggest that, under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth - which greatly increases the scope for habitability in these systems. [Source: NAI Newsletter]

NAI Postdoctoral Fellow Sean Raymond leads a team of authors from NAI's University of Colorado, Boulder, and University of Arizona Teams, and Virtual Planetary Laboratory and University of Washington Alumni Teams in a new publication in Astrobiology. They present analysis of water delivery and planetary habitability in 5 high-resolution simulations forming 15 terrestrial planets. Their results outline a new model for water delivery to terrestrial planets in dynamically calm systems, which may be very common in the Galaxy. [Source: NAI Newsletter]

New work from NAI NASA Ames Research Center Team members and their colleagues published recently in PNAS suggests that the cause for much of the extended red emission, or ERE, is due to closed-shell cationic polycyclic aromatic hydrocarbon, or PAH, dimers. Their work sheds light on the processes involved in carbonaceous dust evolution in the interstellar medium. [Source: NAI Newsletter]

Search for Habitable Planets Outside Earth's Solar System in Astrobiology

"Which planets outside of Earth's Solar System are most likely to be capable of supporting life is a question that will be the focus of both a NASA-sponsored workshop later this year and a special collection of papers in the Spring 2007 (Volume 7, Number 1) issue of Astrobiology, a peer-reviewed journal published by Mary Ann Liebert, Inc."