日時：2008年01月24日(木) 15:30-17:00
場所：自然科学研究科３号館6階ゼミ室（609）
講演者:
石黒 正晃 (Seoul National University)
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Abstract
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Snapshots of comets, which are all around on the Internet, yield information about the dynamics
of cometary particles ejected from nucleus. On the short timescale (< years), the motion of
cometary dust particles is mainly affected by solar radiation pressure as well as solar gravity. Thus
the ratio of the solar radiation pressure with respect to the Sun\u2019s gravity (\u03b2) is widely applied to
describe the motion of the cometary dust particles. Assuming that \u03b2 is a function of particle size,
we lead to the conclusion that (i) short-period comets release dust with mass dominated by the
largest particles (1 mm-10 cm), (ii) small grains were uncommon among these comets, and (iii)
short-period comets constitute a significant fraction of the total mass of interplanetary dust particles.
Despite the conclusion, we face intriguing phenomena that some comets release a large amount
of fine particles in special circumstances as seen in 17P/Holmes.
In this talk, I will expound on the motion of cometary particles and review our recent studies on
the dust tail/trail observations. I will discuss what happen to 17P/Holmes, 9P/Tempel 1,
73P/Schwassmann-Wachamann 3 based on their images.
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