TY - GEN
T1 - Organic chemistry in circumstellar envelopes
T2 - Setting the stage for prebiotic synthesis
AU - Ziurys, Lucy M.
N1 - Funding Information:
This research is supported by NSF grant AST-0607803 and by the NASA through the Astrobiology Institute under Cooperative Agreement No. CAN-02 OSS02.
PY - 2008
Y1 - 2008
N2 - One of the few carbon-rich environments found in interstellar space is the ejecta of asymptotic giant branch (AGB) stars. Such material, which forms a circumstellar envelope, becomes enriched in carbon due to dredge-up phenomena associated with nucleosynthesis. A unique organic synthesis flourishes in the gas phase in these envelopes, and radio and millimeter observations have identified a wide range of C-bearing compounds, including long acetylenic chains such as HC5N, HC7N, C4H, C6H, C8H, C6H, C8H, and C3O. Oxygen-rich envelopes also have a non-negligible carbon chemistry, fostering species such as HCN and HCO+. Phosphorus chemistry appears to be active as well in circumstellar shells, as evidenced by the recent detections of HCP, CCP, and PO. Radio observations also indicate that some fraction of the circumstellar molecular material survives into the planetary nebula stage, and then becomes incorporated into diffuse, and eventually, dense clouds. The complex organic molecules found in dense clouds such as Sgr B2(N) may be the products of seed material that can be traced back to the carbon-enriched circumstellar gas.
AB - One of the few carbon-rich environments found in interstellar space is the ejecta of asymptotic giant branch (AGB) stars. Such material, which forms a circumstellar envelope, becomes enriched in carbon due to dredge-up phenomena associated with nucleosynthesis. A unique organic synthesis flourishes in the gas phase in these envelopes, and radio and millimeter observations have identified a wide range of C-bearing compounds, including long acetylenic chains such as HC5N, HC7N, C4H, C6H, C8H, C6H, C8H, and C3O. Oxygen-rich envelopes also have a non-negligible carbon chemistry, fostering species such as HCN and HCO+. Phosphorus chemistry appears to be active as well in circumstellar shells, as evidenced by the recent detections of HCP, CCP, and PO. Radio observations also indicate that some fraction of the circumstellar molecular material survives into the planetary nebula stage, and then becomes incorporated into diffuse, and eventually, dense clouds. The complex organic molecules found in dense clouds such as Sgr B2(N) may be the products of seed material that can be traced back to the carbon-enriched circumstellar gas.
KW - Astrobiology
KW - Astrochemistry
KW - Circumstellar matter
KW - ISM: abundances
KW - Stars: AGB and post-AGB
KW - Submillimeter
UR - http://www.scopus.com/inward/record.url?scp=53349101102&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=53349101102&partnerID=8YFLogxK
U2 - 10.1017/S174392130802142X
DO - 10.1017/S174392130802142X
M3 - Conference contribution
AN - SCOPUS:53349101102
SN - 9780123456786
T3 - Proceedings of the International Astronomical Union
SP - 147
EP - 156
BT - Organic Matter in Space
ER -