Organic Globules in the Tagish Lake Meteorite: Remnants of the Protosolar Disk

Coordinated transmission electron microscopy and isotopic measurements of organic globules in the Tagish Lake meteorite shows that they have elevated ratios of nitrogen-15 to nitrogen-14 (1.2 to 2 times terrestrial) and of deuterium to hydrogen (2.5 to 9 times terrestrial). These isotopic anomalies...

Full description

Bibliographic Details
Published in:Science
Main Authors: Nakamura-Messenger, Keiko, Messenger, Scott, Keller, Lindsay P., Clemett, Simon J., Zolensky, Michael E.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2006
Subjects:
Tagish
Tagish Lake
Online Access:http://dx.doi.org/10.1126/science.1132175
https://www.science.org/doi/pdf/10.1126/science.1132175
Description
Summary:Coordinated transmission electron microscopy and isotopic measurements of organic globules in the Tagish Lake meteorite shows that they have elevated ratios of nitrogen-15 to nitrogen-14 (1.2 to 2 times terrestrial) and of deuterium to hydrogen (2.5 to 9 times terrestrial). These isotopic anomalies are indicative of mass fractionation during chemical reactions at extremely low temperatures (10 to 20 kelvin), characteristic of cold molecular clouds and the outer protosolar disk. The globules probably originated as organic ice coatings on preexisting grains that were photochemically processed into refractory organic matter. The globules resemble cometary carbon, hydrogen, oxygen, and nitrogen (CHON) particles, suggesting that such grains were important constituents of the solar system starting materials.

Similar Items