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2016.5.30-6.5

5月30日(月)13:30~15:00  太陽系小天体セミナー    南棟2階会議室
May 30 Mon           Solar System Minor Body Seminar   Conference Room, South Bldg.2F

6月1日(水)13:30~14:30  理論コロキウム    コスモス会館会議室
Jun 1 Wed    DTA colloquium    Lecture Room, Cosmos Lodge

6月3日(金)13:30~15:00  太陽天体プラズマセミナー    院生セミナー室
Jun 3 Fri    Solar and Space Plasma Seminar   Student Seminar Room, Subaru Bldg.

6月3日(金)16:00~17:00  国立天文台談話会    大セミナー室
Jun 3 Fri           NAOJ Seminar      Large Seminar Room

詳細は以下をご覧下さい。

5月30日(月)

キャンパス
三鷹
セミナー名
太陽系小天体セミナー
定例・臨時の別
定例
日時
5月30日(月曜日)13時30分~15時
場所
南棟2階会議室
講演者
匠あさみ

連絡先
 名前:渡部潤一

備考
テレビ会議またはスカイプによる参加も可

6月1日(水)

Campus
Mitaka
Seminar
DTA colloquium
Regularly Scheduled/Sporadic
Regularly Scheduled
Date and time
1 June 2016, 13:30-14:30
Place
Conference Room, Cosmos Lodge
Speaker
Shogo Tachibana
Affiliation
Hokkaido University
Title
Timing of gas clearing of the protosolar disk: Constraints from 129I-129Xe ages of solar-wind-rich meteorites
Abstract
Planets in the solar system and extrasolar planets form in protoplanetary disks, which are the natural outcome of the star
formation. The protosolar gas disk also dispersed after the formation of Jupiter and Saturn, resulting in the insufficient gas accretion
onto later-formed Uranus and Neptune cores. However, there has been no chronological constraint when the gas disk dispersed in the solar
system. Here we found that solar-wind-rich portions of gas-rich chondrite breccias are about 10 million years younger than the oldest
solar system solid objects using a 129I-129Xe relative chronometer. The solar-wind gas implantation into asteroids must have occurred in
the absence of disk gas, and thus the disk gas was cleared out completely ~10 million years after the first solid formation. This
could also be the first direct constraint on the timing of the onset of Jupiter and Saturn formation as ~3 million years after the first
solid formation.

Facilitator
-Name:Tomoya Takiwaki

Comment
in English

6月3日(金)

Campus
Mitaka
Seminar
Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic
Regular
Date and time
3 June (Fri), 13:30-15:00
Place
Student Seminar Room, Subaru Bldg.
Speaker
Lee Kyoung-Sun
Affiliation
NAOJ
Title
The quantitative estimation of the energy flux during an explosive chromospheric evaporation in a white light flare kernel observed by Hinode, IRIS, SDO, and RHESSI

Abstract
An X1.6 flare occurred at the AR 12192 on 2014 October 22 around 14:06 UT was observed by Hinode, IRIS, SDO and RHESSI. We analyzed a bright kernel which produces a white light flare with continuum enhancement.
Taking advantage of the spectroscopic observation of the IRIS and EIS, we measured temporal variation of the intensity, Doppler velocity and line width in the bright kernel through the chromosphere and corona. We have also estimated the deposited energy and dissipated energy to understand the white light flare process during the impulsive phase using the RHESSI and IRIS observations. First, we found that the emission in the impulsive phase of the flare kernel shows upflows
(30-300 km/s) in the hotter temperature (Fe XV – Fe XXIV: 2-16 MK) and downflows (30-60 km/s) in the chromospheric temperature lines (He II and Si IV: ? 80kK), which indicates explosive evaporation. Second, the deposited energy flux of electrons from the RHESSI observation is about
2.5 X 10^{10} erg cm^(-2) s^(?1), which can be produce the explosive evaporation and be consistent with the observational Doppler velocity pattern. Third, the Mg II subordinate line blend at 2798.8 A observed from IRIS become emission with a high intensity ratio of line core and wing during the impulsive phase, which indicates a steep temperature gradient in the chromosphere. We estimated quantitative temperature changes, then estimated the dissipated energy in the chromosphere. The dissipated energy is about 4.6-6.7 X 10^{9} erg cm^(?2) s^(?1), about
18-27 % of the deposited energy. It is first time to estimate the dissipated energy during the chromospheric evaporation quantitatively and it shows that the non-thermal electrons have enough power to produce the white light flare for this event.

Facilitator
-Name:Shin Toriumi

6月3日(金)

キャンパス
三鷹
セミナー名
国立天文台談話会
定例・臨時の別
定例
日時
6月3日(金) 16:00-17:00
場所
大セミナー室
講演者
Robert J Rutten
所属
Lingezicht Astrophysics, The Netherlands and Institute for Theoretical Astrophysics, Norway
タイトル
” The challenging solar chromosphere ”
Abstract
The chromosphere is regarded as the most difficult domain of the solar atmosphere. It is where magnetism takes over the role of main structuring agent from the gas pressure and where radiation transfer and escape can not be described with simplifying population equilibria (with one exception: the Planck function holds at ALMA wavelengths). I will start by reviewing the original naming of the chromosphere and how it misleadingly became an extended raised-temperature plateau in static plane-parallel equilibrium models. I will then present modern simulations that demonstrate its dynamical nature and recent observations that suggest that much of what one observes results from prior, fast, small-scale heating events that are hard to detect with current telescopes.

連絡先
-名前: 阿久津 智忠

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