7月2日 （火）13：30～15：00 太陽天体プラズマセミナー 院生セミナー室
Jul 2 Tue Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
7月2日（火）13:30～15:00 太陽系小天体セミナー 南棟２階会議室
Jul 2 Tue Solar System Minor Body Seminar Conference Room, South Bldg.2F
7月3日（水）10：30～12：00 総研大コロキウム 講義室
Jul 3 Wed SOKENDAI colloquium Lecture Room
7月3日（水）13:30 ～15:00 科学研究部コロキウム 開発棟３号館３階会議室
Jul 3 Wed Colloquium of Division of Science Conference room, Instrument Development Bldg. 3 3F
7月5日（金）16：00～17：00 国立天文台談話会 大セミナー室
Jul 5 Fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
7月2日（火）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 2 July (Tue), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Kariyappa Rangaiah
- Affiliation
- Indian Institute of Astrophysics
- Title
- Spatially Resolved Full-Disk Images of the Sun to Understand EUV & UV Irradiance Variability
- Abstract
-
Since the radiative output of the Sun is one of the main driving forces of the terrestrial atmosphere and climate system, the study of solar energy raises is of increasing interest. Although the long-term change in total solar irradiance (the solar energy flux integrated over the entire
spectrum) is considered to be one of the major natural forces of the Earth’s climate system, the study of extreme ultraviolet (EUV) and ultraviolet (UV) irradiance variability is equally important in solar physics and in solar terrestial atmosphere. Indeed, EUV irradiance is the main energy input for the Earth’s upper atmosphere with important effects on the ionosphere and thermosphere. The solar EUV and UV fluxes thus play a major role in Solar-Terrestrial relationships. Understanding their variability is thus an important issue for space weather and climate applications. In this seminar, I will discuss about the EUV & UV solar irradiance variability using spatially resolved full-disk images obtained from SDO/AIA/HMI, PROBA2/SWAP/LYRA and Hinode/XRT space missions and highlight the future research. - Facilitator
- -Name：Masahito Kubo
- Comment
7月2日（火）
- 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
- 7月2日（火曜日）13時30分～15時
- 場所
- 南棟２階会議室
- 講演者
- 古荘玲子
- 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
7月3日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- July 3rd, 2019, 10:30 -12:00
- Place
- Lecture Room
- Speaker
- 石川遼太郎（Ryohtaroh Ishikawa）
- Affiliation
- SOKENDAI 3rd year (D1) (Supervisor: 末松芳法, 勝川行雄, 久保雅仁)
- Title
- Plasma dynamics in the solar photosphere studied by spectral line widths
Abstract(Option): - Speaker
- Yui Kasagi
- Affiliation
- SOKENDAI 1st year (M1) (Supervisor: Takayuki Kotani, Saeko Hayashi, Wako Aoki)
- Title
- Detecting planets around very low mass stars with the radial velocity method
Abstract(Option): - Facilitator
- -Name： Kei Ito
- Comment
7月3日（水）
- キャンパス
- 三鷹
- セミナー名
- 科学研究部コロキウム
- 定例・臨時の別
- 定例
- 日時
- 7月3日（水曜日）13時30分 ～ 15時
- 場所
- 開発棟３階会議室
- 講演者
- Misako Tatsuuma
- 所属
- Univ. of Tokyo
- タイトル
- Rotational Disruption of Irregularly-shaped Dust Aggregates in Planetesimal Formation
- Abstract
-
In recent years, polarized emission at millimeter wavelength in protoplanetary disks has been observed,
some of which are interpreted as the emission of aligned elongated dust grains. For such dust alignment
to occur, it is believed that irregularly-shaped dust grains rotate. In the interstellar space, it has been pointed
out that dust grains rotate due to torque by the interstellar radiation and are disrupted by centrifugal force
(Hoang 2019, ApJ, 876, 13). In this process, the centrifugal force due to the rotational motion, that is tensile
stress, is applied to the dust grains and they are disrupted if the tensile stress is larger than their tensile strength.
In this work, we theoretically calculate whether or not dust grains are rotationally disrupted during their coagulation
in a protoplanetary disk. We use the tensile strength of porous dust aggregates (Tatsuuma et al. 2019, ApJ, 874, 159).
We assume two driving sources of the rotational motion of the dust aggregates: the torques from the radiation field and
the gas flow in the disk. We calculate the constant rotational velocity of the dust aggregates by assuming that their
rotational motion is damped by the surrounding gas and we obtain the tensile stress due to the centrifugal force.
As a result, we find that highly porous dust aggregates are disrupted if their mass is larger than ~ 10^{10} g.
We also find that the dominant driving source of the torque is not the radiation field but the gas flow, unlike in the
interstellar space. This is due to the weak energy density of the radiation field at the disk midplane compared to
that in the interstellar space. The results suggest that the growth of irregularly-shaped dust aggregates can be
halted due to rotational disruption if they are highly porous. - 連絡先
- 名前：Akimasa Kataoka
7月5日（金）
- Campus
- Mitaka
- Seminar
- NAOJ seminar
- Regularly Scheduled/Sporadic
- Scheduled
- Date and time
- Fri 5 Jul 16:00～17:00
- Place
- Large Seminar Room
- Speaker
- Tim Heckman
- Affiliation
- Johns Hopkins University
- Title
- Feedback and the Evolution of Galaxies and Black Holes
- Abstract
-
I will summarize our current understanding of the processes that govern the formation and co-evolution of galaxies and their supermassive black holes (SMBH).
I will pose several of the most fundamental shortcomings of our current models and then examine how they may be addressed by the effects of the feedback provided by massive stars and actively growing SMBH.
My focus will be on what we have learned so far (largely from observations of the contemporary universe), and I will conclude by describing future prospects using a new generation of facilities.
I will do my best to give talk that minimizes jargon and stresses the basic underlying physical processes. - Facilitator
- -Name：Matsuda, Yuichi