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Record Details

Record 47 of 42672
Spectral Characteristic of Tholin Produced from Possible Early Earth Atmospheres and its Role in Antigreenhouse Effect on Early Earth
Author and Affiliation:
Khare, B. N.(Search for Extraterrestrial Intelligence Inst., CA, United States)
Imanaka, H.(Search for Extraterrestrial Intelligence Inst., CA, United States)
Wilhite, P.(NASA Ames Research Center, Moffett Field, CA, United States)
McKay, C.(NASA Ames Research Center, Moffett Field, CA, United States)
Bakes, E.(Search for Extraterrestrial Intelligence Inst., CA, United States)
Cruikshank, D. P.(NASA Ames Research Center, Moffett Field, CA, United States)
Arakawa, E. T.(Oak Ridge National Lab., TN, United States)
Abstract: We have produced organic material simulating a methane photochemical haze in a CO2- rich atmosphere of the early Earth by irradiating gas mixtures in an inductively coupled cold plasma chamber with pressure approx. 0.25 mbar at 100 W total power. The flow rate was 24 cm3 min. We added progressively higher levels of CH, by combining gas mixtures of N2/CH4 (9/1) and N2/CO2 (9/1) to change the ratio of CH4/CO2. Tholin was accumulated for 5 hours in each experiment; the onset of tholin formation is in the range CH4/CO2 = 0.5 to 1. As the mixing ratio of CH, is increased, the production rate of the brownish tholin film increases. IR spectra showed the C-H and N-H bands similar to that of Titan tholin and closely resemble Titan tholin made at 0.13 mbar pressure. A decrease in the CH bonds on decreasing CH4/CO2 is noted. Ether bands (-(2-O-C) were tentatively detected, but no detectable carbonyl (C=O) band was found. The absorption in the UV region for the early Earth tholin is found to be substantially greater than the Titan tholin. Quantitative values of the optical constants of early Earth tholin are currently being measured.
Publication Date: Jan 01, 2003
Document ID:
20030071230
(Acquired Oct 07, 2003)
Subject Category: GEOPHYSICS
Document Type: Preprint
Meeting Information: Exobiology Conference; 21-25 Aug. 2003; Moffett Field, CA; United States
Contract/Grant/Task Num: RTOP 344-58-22-07
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA, United States
Organization Source: NASA Ames Research Center; Moffett Field, CA, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: GREENHOUSE EFFECT; EARTH ATMOSPHERE; HAZE; METHANE; OPTICAL PROPERTIES; GEOPHYSICS
Availability Source: Other Sources
Availability Notes: Abstract Only
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