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작성일 : 14-09-26 10:42
09월 30일(화요일) 우주과학과 세미나 안내
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안녕하세요. 우주과학과 우주탐사학과 여러분.
세미나 공지 드리겠습니다.
 
이번 세미나는 9월 30일 오후 4시 30분 천문대 영상실에서 있습니다.
 
Harvard-Smithsonian Center for Astrophysics 의 Dr. John C. Raymond 께서 " The Sungrazing Comet Lovejoy as a Probe of the Solar Corona " 라는 제목의 강연을 해 주실 예정입니다.
 
강연은 영어로 진행됩니다.
 
세미나 참석을 원하시는 분은 세미나 시작 10분 전까지 입실해 주시기 바랍니다.
 
많은 참석 부탁드립니다. 감사합니다.
 
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Dear Colleagues,
 
There will be an Astronomy and Space Science seminar on 30th, 4:30 PM,  in Auditorium, Kyung Hee Astronomical Observatory.
Dr. John C. Raymond of Harvard-Smithsonian Center for Astrophysics will give a presentation about " The Sungrazing Comet Lovejoy as a Probe of the Solar Corona ".
 
The language of the seminar will be English.
 
You are asked to join the seminar five to ten minutes before it starts. Your attendance will greatly be appreciated.
 
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Seminar Information
 
When: Sep 30th (Tues), 4:30 PM
 
Where: Auditorium, Kyung Hee Astronomical Observatory.
 
Speaker: Dr. John C. Raymond
 
Title : The Sungrazing Comet Lovejoy as a Probe of the Solar Corona
Abstract : 
Comet Lovejoy passed just 0.2 solar radii above the surface of the Sun. EUV images show a remarkable set of evenly spaced striations due to magnetic field structure.  In each striation, the emission moves along the magnetic field and stretches with time. When oxygen atoms from the comet become ionized and behave as pickup ions and produce the observed emission as they pass through different ionization stages.  Analysis of images and spectra yields the size of
the comet nucleus and its composition.  The intensity structure indicates density contrasts of a factor of 6 between neighboring magnetic flux tubes on scales of around 4000 km. The implied variation in Alfven speed results in dispersion and dissipatation of Alfven waves, which will affect the heating of the corona and the driving of the solar wind.