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Stellar Magnetic Activity Measure Based on IUE Mg II h+k Emission Lines of Main-Sequence G Stars

Choi, Hwajin; Yi, Yu; Kim, Dowoon

Stellar magnetic activity is important for formulating the evolution of the star. To represent the stellar magnetic activity, the S index is defined using the Ca II H+K flux measure from the Mount Wilson Observatory. Mg II lines are generated in a manner similar to the formation of Ca II lines, which are more sensitive to weak chromospheric activi…

Streaming Circumnuclear Gas of the Seyfert 2 Galaxy NGC 5728

Ferruit, Pierre; Hyung, Siek; Son, Dong-Hoon +1 more

Chemical Abundances of the Symbiotic Nova AG Pegasi

Hyung, Siek; Kim, Hyouk

High Dispersion Optical Spectroscopy of Planetary Nebulae

Hyung, Siek

IUE Spectra of the Seyfert 1 Galaxies Mrk 335 and NGC 4051

Hyung, Siek; Kim, Hyouk; Lee, Woo Baik +3 more

The international ultraviolet explorer (IUE) spectra of a low dispersion ~6 A, have been investigated for two Seyfert 1 galaxies, Mrk 335 and NGC 4051, well known for the line variability. The electron densities of broad line region (BLR) of these variable Seyfert 1 galaxies have been derived, which showed a non-linear abrupt variation from 1e+8 t…

The Swings Effects of the A-X System and v" = 1-0 Band of CO

Kim, Sang-Joon

We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the 1200 - 1800 A-…