2013 Annual Science Report
Rensselaer Polytechnic Institute Reporting | SEP 2012 – AUG 2013
Our investigators are members of the New York Center for Astrobiology (NYCA; www.origins.rpi.edu), based at Rensselaer Polytechnic Institute (RPI) in partnership with Syracuse University, the University at Albany, the University of Arizona, and Albion College. Our research is devoted to elucidating the origins of both life itself and of habitable planetary environments, in our own Solar System and in planet-forming regions around other stars: in short, to develop realistic, widely applicable models for the emergence of molecular complexity leading to life. This is being accomplished through a synergy of interdisciplinary research that unifies astronomical observations, laboratory experiments and computational modeling. It addresses several goals of the Astrobiology Roadmap, including Goal 1 (potential for habitable planets), Goal 2 (life in our Solar System), Goal 3 (origins of life), Goal 4 (Earth’s early biosphere and environment), and Goal 7 (signatures of life).
An online summary of highlights and accomplishments of our team may be found here:
Our team completed a search for a new junior faculty member in Astrobiology at RPI during the reporting period. The multidisciplinary search committee was chaired by Doug Whittet and composed entirely of members of our NAI team. A total of 65 applications were received. Dr Karyn Rogers of the Carnegie Institute was appointed: she joined the RPI faculty in August 2013 as an assistant professor in the Department of Earth & Environmental Sciences. Dr. Rogers’ research expertise and interests concern geochemical modeling to evaluate water-rock-microbial interactions, microbial metabolic diversity in modern and ancient hydrothermal systems, the exploration of microbial activity at extreme temperatures and pressures, and the potential for life on Mars. Her expertise will strengthen and synergize with our existing research on the origins of and conditions for life.
Our research is grouped into eight interconnected projects that form a logical sequence, from interstellar precursors through protoplanetary disks and the solar nebula to the early Earth and Mars. Some highlights are summarized here; further details may be found in the individual project reports and publications.
New stars and planetary systems are born within the cold, dark regions of interstellar clouds. To help us better understand the origins of our own solar system, and the myriad of others now known to exist, astronomers study these clouds at the evolutionary phase immediately preceding stellar birth. A good example is the object known as Lynds 183, a small, compact dark cloud known from observations made at radio wavelengths to be rich in gaseous interstellar molecules such as carbon monoxide, ammonia, methanol and hydrogen cyanide, all existing at temperatures as low as 10 Kelvin. A new study by Whittet’s group, recently published in the Astrophysical Journal, helps to expand our picture of the cloud by focusing on the solids – silicate dust and ices – that are potential raw materials for future planets. Infrared data obtained from NASA’s Spitzer Space Telescope and the Mauna Kea Observatory in Hawaii was used to search for the spectroscopic fingerprints of these material. We found that the silicate particles serve as nucleation centers for the growth of ices that contain not only H2O but also CO and CO2, and that this can occur in the outer layers of the cloud where there is just enough shielding from the harsh environment of space to allow the ices to survive. These results add to the growing evidence that the water and other volatiles needed to build habitable environments on earth-like planets are easily formed at the lowest temperatures in prestellar clouds. When stars are born inside them, the resulting increase in temperature and radiation exposure can drive a different kind of chemistry that can form complex organic molecules out of these simple ices.
The diverse inventory of amino acids and other organic molecules found in meteorites implies that asteroids once provided warm environments conducive to prebiotic chemistry. A goal of our research is to understand the physical mechanisms which heated asteroids and their prevalence in other protoplanetary disks. The decay of short-lived radionuclides such as Aluminum-26 is one such mechanism, but reliable estimates show that it is insufficient to provide the degrees of heating needed to explain the thermal state of the current asteroid population. Another widely discussed mechanism is induction heating, described in a classic series of papers by C.P. Sonett and collaborators, published in the late 1960s and early 1970s. Menzel & Roberge (2013) have completed a re-examination of the induction heating mechanism. Classical induction postulates that the asteroids were swept by a powerful, fully-ionized T Tauri wind from the young Sun. Menzel & Roberge revised this scenario to account for modern ideas about protoplanetary disks. Their principal results are (i) that classical induction theory is based on a subtle misunderstanding of the underlying physics; (ii) the correct physics predicts a new “electrodynamic heating” mechanism which is viable in weakly-ionized disks; (iii) for some flow geometries the rate of electrodynamic heating rate is zero; (iv) for other geometries electrodynamic heating can have a rate comparable to classical induction. This work has important implications for planetary science and astrobiology. It was featured in a recent press release : “Rensselaer Researchers Propose New Theory to Explain Seeds of Life in Asteroids”.
A new collaboration was initiated between Wayne Roberge’s group and Pablo Suarez, an applied mathematician at Delaware State University (DSU). Suarez was awarded an NAI-sponsored Minority Institution Research Support (MIRS) fellowship for this collaboration, for the purpose of developing adaptive mesh refinement techniques applied to a code that predicts the excitation spectra of shocked molecular gas in protostellar outflow regions. Suarez spent 10 weeks at RPI in summer 2013 working on this problem. Since then he has recruited two DSU students into the project. Our team will fund Suarez and the two students to visit NYCA again in summer 2014. A goal of the project is to predict diagnostic spectral lines that may be observed, e.g., with the Stratospheric Observatory for Infrared Astronomy (SOFIA), providing new tests for models of chemical evolution in protoplanetary environments.
The search for habitable environments on Mars and elsewhere in our solar system requires an understanding of the role minerals may have played in the development of potential life forms and when hydrous minerals formed on planetary surfaces. In a study led by the Baldwin group at Syracuse University, we are evaluating the potential of noble gases in Martian minerals to record the timing of surface and atmospheric conditions that can be used to characterize past habitable environments on Mars. By investigating the kinetics of noble gases in minerals, known to occur on Earth, Mars and the Moon, we aim to understand how common minerals found in our solar system can be used to determine the timing and rates of processes relevant to astrobiology. Results are aimed at developing protocols to analyze and properly interpret ages measured on samples from future Mars sample return missions. Building upon results of Ar diffusion experiments of jarosite reported previously, and models of Ar retention in jarosite and He in hematite, we determined conditions under which these mineral’s “radiometric clocks” can be reset, and we developed a sampling strategy to determine the timing, duration and rates of water saturation in rocks on the surface of Mars (Kula & Baldwin 2012). On Mars, jarosite is thought to have formed during the acidic, water limited, sulphate-forming era (e.g., Hesperian). In the past year we have focused on the development of noble gas techniques that can be applied to minerals that also formed when warmer, wet conditions were prevalent on Mars (e.g., Noachian). The goal is to develop strategies to fully extract information from the rock record about environmental transitions that can then be used to assess the potential role of minerals in the development of life.
Ongoing research in the prebiotic catalytic chemistry group (Ferris, Joshi, et al.) is studying abiotic synthesis of RNA by catalysis on montmorillonite clay minerals. Work in the past year has focused on the catalytic efficiency of different montmorillonites, their probable availability on the early Earth, and the nature of catalytic activity that could have led to chiral selectivity on Earth. A preference for homochiral selection in the montmorillonite-catalyzed reactions of D, L-ImpA was found. A progressive increase in homochiral selectivity with increase in the chain length was observed, suggesting that each homochiral oligomer acted as a chiral auxiliary in the formation of the next higher oligomer. Amongst the more than two hundred clay minerals investigated as catalysts, only a few have been found to be excellent. The less efficient catalysts were investigated to test how they perform in an alternative reaction system in which a nucleoside is first adsorbed on to the clay and the resulting complex is treated with an activated nucleotide. Representative clay minerals were able to promote efficient dimer synthesis, leading to a proof of concept that the nominally poor catalysts can assist in the synthesis of shorter oligomers, which could have been formed in a vast number of prebiotic locations.
Education and Public Outreach
Our education and public outreach program has continued to be highly successful. The 5th annual Astrobiology Teachers Academy was held at RPI, July 22-25, and attended by 16 high school and middle school science teachers from the Capital District and elsewhere in New York State. The teachers worked with NYCA faculty and with education experts from the Association for the Cooperative Advancement of Science Education to develop ideas, strategies and resources to integrate astrobiological themes into their classrooms. The intrinsic fascination of astrobiology and the search for life on other planets continues to provide a highly effective means of engaging the students in the STEM disciplines. Attendees included 8 returning teachers who gave presentations on their past activities and engaged in mentoring those new to the academy. See the Academy’s facebook page for further information.
RPI celebrated its 6th successive year in 2013 as a host to the ExxonMobil Bernard Harris Summer Science Camp. Again, the program was focused on astrobiology, with 50 campers from Albany-area schools engaged in designing future missions to Mars to search for life on the red planet. For further information and images, see out this RPI news story and the Camp’s Facebook page.
Progress of NAI-supported Graduate Students
RPI graduate student Paul Mayeur successfully defended his doctoral thesis in June 2013;. His degree is in Multidisciplinary Science with a focus in Astrobiology Education. He is now employed as a communication consultant with a software company.
RPI graduate student Emily Hardegree-Ullman was selected for a 6-month internment (January – June 2013) to carry out research at the Infrared Processing and Analysis Center at Caltech/JPL on the spectra of polycyclic aromatic hydrocarbons absorbed in interstellar ice analogs. She recently completed a publication on this work submitted to Astrophysical Journal.
RPI graduate student Bradley Burcar became the first recipient of the James P. Ferris Graduate Fellowship in Astrobiology, endowed by a gift to RPI from the Emily Landecker Foundation in honor of RPI professor emeritus Jim Ferris in recognition of his pioneering contributions to astrobiology.
As a result of the commitment and community engagement of our postdoctoral and graduate student researchers, RPI has been selected to host the Astrobiology Graduate Conference in 2014.