10月12日（水）10：30～12：00 総研大コロキウム 中央棟（北）1F講義室
Oct 12 wed SOKENDAI Colloquium Lecture room
10月14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
Oct 14 fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
10月14日（金）16：00～17：00 国立天文台談話会 大セミナー室
Oct 14 fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
10月12日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI Colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 12 October, 2016, 10:30-12:00
- Place
- Lecture room
- Speaker
- Speaker：1.Koki Okutomi
- Affiliation
- SOKENDAI, D2 (Supervisor; Yoichi Aso)
- Title
- Control Strategy of Vibration Isolation System in KAGRA
- Abstract
- Laser interferometric gravitational-wave detector KAGRA has vibration isolation systems called SAS which attenuate fluctuation of mirrors from seismic disturbance. The largest type of SAS is a multi-stage pendulum consists of 9 suspended stages. We need to control the mirror with the complicated system to operate the laser interferometer. In this talk, I present a strategy how to control the SAS and measurements for a sensor/actuator unit related to the control strategy.
- Speaker
- Speaker：2.Tomonari Michiyama
- Affiliation
- SOKENDAI, D1 (Supervisor; Daisuke Iono)
- Title
- Chemical composition in merging galaxy NGC3256
- Abstract
- Facilitator
- -Name：Kotomi Taniguchi
- Comment
- TV conference system is available connecting from Nobeyama, Hawaii, Mizusawa, and Okayama.
10月14日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 14 October (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Yuki Tanaka
- Affiliation
- NAOJ
- Title
- Atmospheric Structures and Mass Loss: Magnetically Driven Wind from Hot Gaseous Planets
- Abstract
-
Transit spectroscopy is the powerful tool to investigate properties of exoplanetary atmospheres such as its composition, structures, and escape. Several transit observations in the UV wavelength have been suggested that hot Jupiters have high-temperature hydrogen upper atmospheres, and the existence of a large amount of atmospheric escape from the upper atmospheres. For example, a mass-loss rate from the hot Jupiter HD 209458b is estimated to be at least 10^10 g/s. In addition to this, a huge comet-tail like exosphere consists of the escaping atmosphere are detected around a hot Neptune-mass exoplanet GJ 436b. It is thought that heating by the X-ray and extreme ultraviolet (XUV) radiation from central stars is the main mechanism to drive the atmospheric escape, but a driving mechanism of atmospheric escape that includes planetary magnetic fields has not been investigated so far.
Here we propose a new mechanism in which the atmospheric escape is driven by the dissipation of magnetohydrodynamic (MHD) waves in the upper atmospheres. We performed MHD simulations and show that the dissipation of MHD waves in the upper atmosphere can drive a large amount of atmospheric escape and also can heat up the upper atmosphere.
I also discuss parameter dependence of the mass-loss rate and atmospheric structures, and application of this model to the hot Neptune GJ 436b. - Facilitator
- -Name：Shin Toriumi
- Comment
10月14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
- 10月14日（金） 16:00-17:00
- 場所
- 大セミナー室
- 講演者
- Amiel Sternberg
- 所属
- Physics, Sackler School of Physics & Astronomy, Tel Aviv University
- タイトル
- The Atomic-to-Molecular (HI-to-H2) Transition in Galaxy Star-Forming Regions
- Abstract
- The atomic-to-molecular (HI-to-H2) phase transition is of fundamental importance for regulating star-formation in galaxies. I will describe new analytic theory for interstellar HI-to-H2 transitions, based on fundamental physical principles. I will discuss my general-purpose formula for the total HI mass surface densities produced by photodissociation in optically thick media, valid for beamed or isotropic radiation, gradual to sharp transitions, and for arbitrary metallicity. The general theory may be broadly applied for interpreting observations of atomic and molecular gas in individual Galactic sources, for setting star-formation thresholds, for understanding global galaxy properties on large scales, and may also be incorporated into hydrodynamics simulations.
- 連絡先
- -名前： 矢野 太平
以上