Synthesis of organic matter by stars and its effect on the origin of life on earth

Abstract

The last 10(5) years of stellar evolution represents the most active period of synthesis of organic compounds in a star’s life. Over 60 gas-phase molecules, including rings, radicals, and molecular ions have been identified by millimeter-wave and infrared spectroscopic observations through their rotational and vibrational transitions. Space infrared spectroscopic observations of emissions from the stretching and bending modes of aliphatic and aromatic compounds have revealed a continuous synthesis of organic material over a period of only a few thousand years. These organic gases and solids are ejected into the interstellar medium through stellar winds and spread all over the Galaxy. Isotopic analysis of meteorites and interplanetary dust collected in the upper atmospheres have revealed the presence of pre-solar grains similar to those formed in evolved stars. This provides a direct link between star dust and the solar system and raises the possibility that the early solar system was chemically enriched by stellar ejecta. In this paper, we summarize the chemical structure of stellar organic matter and compare them to the organics found in meteorites, comets, asteroids, planetary satellites, and interplanetary particles. The possibility that external delivery of stellar organic matter had contributed to the origin of life of Earth is discussed.