下記の講演会を行います。よろしくご参加下さい。

講演者のEberhard Gruen 教授（Max Planck Inst.　Heidelberg & 
University of Hawaii）は、宇宙空間でのダスト計測の第一人者です。
6月 2日（水）から5日（土）まで神戸に滞在されます。この機会を
研究交流にも活用して下さい。

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COE学術講演会のお知らせ


日時：２００4年6月3日（木）
１６：４０〜１８：００
場所：自然科学３号館６階セミナー室（６０９）


Prof. Eberhard Gruen
Max-Planck Inst. fuer Kernphysik, Heidelberg, Germany& HIGP, Univ. of 
Hawaii, USA

DUST ASTRONOMY
Dust particles, like photons, are born at remote sites in space and 
time, and carry from there information that may not be accessible to 
direct investigation.

In stellar winds of evolved stars, new dust is formed and is injected 
into interstellar space. Young stardust is mixed with old 
heavily-processed diffuse interstellar dust, and is subject to 
passing supernova shocks and ultraviolet radiation. Dusty clouds 
emerge. The protostar environment is a fertile ground for solids on 
all size scales to form, from dust grains to planets. Star formation 
in cool molecular clouds becomes both a sink of old dust and a source 
of new dust. Dust in a planetary system is the most processed of the 
different populations of cosmic dust. Interplanetary dust is 
permanently replenished by dust ejected from cometary nuclei, the 
most pristine bodies in the inner planetary system, and released from 
collisions in the asteroid and Kuiper belts. In our solar system, 
interplanetary dust exists alongside interstellar dust, which is 
flowing through the solar system, offering a physical link between 
our planetary system and the stars.

The dynamics of dust particles is affected by gravitational and 
magnetic fields. Dust trajectories trace out their radiation, gas, 
plasma, and dust environments. By accurate dust trajectory 
measurements we can derive their place of origin: comets, asteroids, 
or even interstellar space. From the particles' bulk properties and 
their chemical composition we are able to infer properties of the 
environments out of which the particles were formed and in which they 
were subsequently altered. The combination of trajectory 
determination and chemical analyses on the same dust  particle, is 
called dust astronomy. Recent developments of in-situ dust detectors 
allow us to combine sensors of these capabilities into a single dust 
telescope that is carried by a dust observatory satellite in space.

A state-of-the-art dust telescope is capable of providing mass, 
velocity, physical and chemical information of individual dust grains 
in space. Dust particles' trajectories are determined by the 
measurement of the electric signals that are induced when a charged 
grain flies through a position sensitive electrode system. 
High-resolution dust mass analyzers that provide chemical composition 
of dust particles have been flown on the Halley missions and are 
currently flying on the Stardust mission. Targets for a dust 
telescope are dust from the local interstellar medium, meteor stream 
dust, cometary, asteroidal, and dust emitted from planets and their 
satellites.

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