제목: Structure and Evolution of AGB stars​​

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​​​​​​​​​​​​​​​​​​연사: Dr. Kyung-Won Suh (충북대학교)​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

장소: 과학관 B103호​​

Abstract:

AGB stars are believed to be the primary sources of dust in galaxies. We investigate their properties using observational data spanning the visual, infrared, and radio bands. By integrating datasets from Gaia DR3, 2MASS, IRAS, ISO, Akari, MSX, WISE, AAVSO, SIMBAD, and the maser emission database, we compare observational data with theoretical models of AGB stars. Given the limitations of Gaia DR3 parallax-based distances for most AGB stars, we derive theoretical distances through radiative transfer modeling of dust shells, fitting observed and synthetic spectral energy distributions (SEDs). These distances, combined with extinction corrections, enable the calculation of absolute magnitudes and intrinsic colors, which we use to construct various color-magnitude diagrams(CMDs) and two-color diagrams (2CDs) for AGB stars. The theoretical radiative transfer models can explain the observational trends, particularly in the infrared. We analyze maser sources associated with AGB stars, examining absolute OH maser fluxes in relation to infrared colors. We explore the infrared variability of AGB stars using 16 years of WISE photometric data. We present a new catalog of 70,877 O-rich AGB stars and 7,163 C-rich AGB stars in our Galaxy, providing enhanced reliability and expanded datasets for future research.​​​