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Kim, Sang-Joon
- Publications of The Korean Astronomical Society
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- v.12 no.1
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- pp.85-98
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- 1997
The A-X (0-0) band of CS, which appears in high dispersion IUE spectra of comets Halley (1982i) and Wilson (19861), has been investigated in detail. We developed models, which include fluorescence and collisional processes We found that in order to account for the observed emission band precisely, IUE tracking errors should be included in line shape calculations it has been found that rotational excitation by electrons is a dominant process in determining populations of rotational ground states. We derived an electron density of $2.0\times10^4/cm^3$ at several thousand kilometers from the comet Wilson's nucleus by examining collisional influence on the CS band structure. We presented a band model for the 0-0 band of $C^{34}S$ and discussed the detectability of $^{34}S$ spectroscopically.
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Ishiguro, Masateru
- The Bulletin of The Korean Astronomical Society
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- v.35 no.1
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- pp.87.1-87.1
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- 2010
Main-belt comets (hereafter MBCs) are one of the hottest topics in the solar system astronomy. They are objects orbiting in the main asteroid belt which show cometary activity. Unlike most comets, which spend most of their orbit beyond 5AU from the Sun, MBCs follow near-circular orbits within the asteroid belt that are indistinguishable from the orbits of major population of the asteroids. P/2010 A2, the fifth MBC, was discovered by on January 6, 2010 by Lincoln Near-Earth Asteroid Research. It passed its perihelion at 2.01AU on December 3, 2009, about a month before it was discovered. With an aphelion of only 2.6 AU, P/2010 A2 spends all of its time inside of the frostline ~2.7 AU. We made observations of P/2010 A2 with Nishi-Harima Astronomical Observatory 2-m telescope only a week after the discovery. From the observed images, we found that the dust cloud was composed of large particles (>1mm) impulsively ejected between March and June, 2009. No coma was detected by our observations, suggesting that this object was no longer active. Consequently, we conjecture that these dust particles could be released by the impact collision among asteroids.
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