Scientific Rationale

In the last one million years of stellar evolution, from the late asymptotic giant branch to planetary nebulae to white dwarfs, we witness fascinating physical and chemical processes at work. With the nucleosynthesis of carbon, we see the rapid synthesis of molecules, first in the stellar atmosphere, and later in the stellar winds. The stellar winds completely deplete the stellar envelope and expose the hot core of the star. A change in the stellar wind mechanism leads to a fast wind, which compresses the previous ejecta into a planetary nebula. At the same time, a magical metamorphosis takes place, transforming the spherical circumstellar envelope into bipolar (and even multipolar) morphological structures through yet-unknown physical mechanisms.

Along with the rapidly increasing temperature of the central star, we see the beginning of photoionization and the emission of strong atomic lines from the nebulae. In these nebulae, we see the emergence of complex organic compounds of aromatic and aliphatic structures, as well as large molecules such as fullerene. How such complex organics are synthesized under an extremely low density environment is not understood. These complex molecules and solids are spread throughout the interstellar medium, and may have enriched our primordial Solar System.

In this conference, we will address the many unsolved mysteries in the late stages of stellar evolution. These issues have bearings on our understanding of stellar evolution, chemical synthesis, astrochemistry, and may be even the origin of life.

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