Bulletin of the American Physical Society
39th Annual Meeting of the APS Division of Atomic, Molecular, and Optical Physics
Volume 53, Number 7
Tuesday–Saturday, May 27–31, 2008; State College, Pennsylvania
Session Q2: Molecular Basis of Astrobiology |
Hide Abstracts |
Chair: Daniel Savin, Columbia University Room: Kern Building 112 |
Friday, May 30, 2008 2:00PM - 2:36PM |
Q2.00001: Protons to Planets: Mapping the Routes to Life Invited Speaker: In this talk I will review some of the extraordinary advances that have been made in the search for the potential harbors for life in the Universe. The discovery of exoplanets, and the nascent science of their study, has been revolutionary. Together with the exploration of our own solar system and the investigation of circumstellar disks around young stars, a picture is being revealed of how the ingredients of planets are assembled. To take this to the next step, and ask how life might be initiated on these worlds we must integrate these efforts with a knowledge of the chemistry taking place in environments from tenuous interstellar gas clouds to the rough and tumble of a proto-planetary system. Many of the key questions are seen across multiple disciplines, and I will attempt to summarize some of these. [Preview Abstract] |
Friday, May 30, 2008 2:36PM - 3:12PM |
Q2.00002: Formation of Biomolecule Precursors in the Interstellar Medium and Planetary Atmospheres Invited Speaker: It has been a subject of intense discussions to which extent biomolecule precursors have been synthesized on planetary surfaces in atmospheres or in the interstellar medium (ISM). Whereas more advanced biomolecules like amino acids are not expected to survive the strong UV field present under disk and planetary formation, this may not hold for precursor molecules like nitriles, which are present abundantly in the ISM and could be delivered to plantes by comets or meteorites. In planetary atmospheres, nitriles can polymerize to tholines, which upon hydrolysis can form amino acids and nucleobases. Also, the Cassini-Huygens mission revealed that protonated nitriles are abundant in Titan's atmosphere, which possibly resembles the one of early Earth. Due to the high proton affinity of their parent compounds, DR is the main destruction pathway of these ions. We present measurements on the rate constants and branching ratios of the DR of several important protonated nitriles in a storage ring experiment. [Preview Abstract] |
Friday, May 30, 2008 3:12PM - 3:48PM |
Q2.00003: The Enigmatic Diffuse Interstellar Bands: A Reservoir of Organic Material Invited Speaker: The diffuse interstellar medium of our galaxy contains about 3 billion solar masses of atomic hydrogen, or $\sim $3$\times $10$^{66}$ H atoms. The inventory of identified heavy-atom-containing molecules in diffuse clouds includes CH, CH$^{+}$, NH, OH, C$_{2}$, CN, C$_{2}$H, and C$_{3}$H$_{2}$, and totals to roughly $\sim $10$^{59}$ in number. However, a ubiquitous set of optical absorption lines known as the diffuse interstellar bands (DIBs) belies the likely presence of $\sim $10$^{58}$ large organic molecules that have yet to be identified. The first of the DIBs were observed in 1919, but despite many decades of intensive efforts by laboratory spectroscopists and astronomers the identities of the molecular carriers of the DIBs remain a mystery. After reviewing the history of the DIBs, I will discuss some preliminary results from a large-scale DIBs observing campaign that was conducted on over 119 nights between 1999 and 2003, using the 3.5-meter telescope at the Apache Point Observatory. This survey, undertaken by a collaboration led by Don York at the University of Chicago, has produced high-resolution, high signal-to-noise ratio spectra of over 160 stars, spanning the entire optical region from 3600--10200 {\AA}. In particular, I will focus on two ongoing efforts. The first is the generation of a comprehensive spectral atlas of the DIBs based on four heavily reddened sightlines; this atlas will be of great use to spectroscopists who wish to compare their laboratory spectra to interstellar spectra (in hopes of finding a match!). The second is the search for correlations among the different DIBs, and especially the search for sets of DIBs that always have the same relative intensities in different sightlines. Such sets would represent the electronic spectra of individual molecular carriers of the DIBs, and could provide hints about which species should be considered for additional laboratory spectroscopic studies. [Preview Abstract] |
Friday, May 30, 2008 3:48PM - 4:24PM |
Q2.00004: Hot corinos: pre-biotic molecules in solar-type protostars Invited Speaker: One of the major goals of modern astrophysics is to understand the formation of our Solar System. Since low-mass protostars are suns in the making, the study of these objects and their environment provides one of the best ways to investigate the Sun's formation process and to peek in the past history of our Solar System. In particular, by studying the chemistry occurring in Class 0 sources (the earliest known phases in the evolutionary scenario of low-mass protostars), we can uncover the formation and evolution of pre-biotic molecules in the precursors of solar-type stars. Such molecules (e.g. CH$_3$CN, HCOOCH$_3$, HCOOH, etc) have been discovered in IRAS16293$-$2422, the prototype of Class 0 sources, proving the existence of hot corinos, the inner regions of the protostellar envelope where the icy grain mantles sublimate. Some of these molecules have also been observed in comets in our Solar System, raising the question of whether (and if so, how) the chemistry of Class 0 objects affects the chemical composition of the protoplanetary disk material from which comets and other planetary bodies form. However, it is first necessary to determine whether hot corinos are ubiquitous in low-mass protostars or if IRAS16293$-$2422 is an exception. In this talk, I present the steps I took to search, find and characterize other hot corinos, using the IRAM-30m and PdBI. To try and discriminate whether complex organic molecules form via gas-phase or grain-surface reactions, I confront the possible formation pathways with the results of my observations, and I also compare hot corinos with their high-mass analogs, the hot cores. I will conclude with some prospects for the study of pre-biotic molecules in young solar-type objects and questions that future facilities will address. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700