10月８日（火）14：00～ ALMA-J Seminar ALMA棟１階 102
Oct 8 Tue ALMA-J Seminar ALMA building, first floor, room 102
10月９日（水）10：30～12：00 総研大コロキウム 講義室
Oct 9 Wed SOKENDAI colloquium Lecture Room
10月11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 11 Fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
詳細は以下をご覧下さい。
10月8日（火）
- Campus
- Mitaka
- Seminar
- ALMA-J Seminar
- Regularly Scheduled/Sporadic
- Regularly Schedule
- Date and time
- Tuesday 8, October at 2 PM
- Place
- ALMA building, first floor, room 102
- Speaker
- Seokho Lee
- Affiliation
- NAOJ
- Title
- The circumstellar environment around the embedded protostar EC 53
- Abstract
-
Most protostars have fainter luminosities than expected from steady accretion over the protostellar lifetime. One promising solution is the episodic accretion. EC 53 is an embedded protostar with quasi-periodic emission in the near-IR and sub-mm.
We use ALMA high-resolution observations of molecular line and continuum emission to describe the circumstellar environment of EC 53. The continuum image reveals a disk with a flux that suggests a mass of 0.075 solar mass, much less than the estimated mass in the envelope, and an in-band spectral index that indicates grain growth to centimeter sizes. Molecular lines trace the outflow cavity walls, infalling and rotating envelope, and/or the Keplerian disk. The rotation profile of the C17O 3-2 line emission cannot isolate the Keplerian motion clearly although the lower limit of the protostellar mass can be calculated as 0.3 +/- 0.1 solar mass, if the Keplerian motion is adopted. The weak CH3OH emission, which is anti-correlated with the H13CO+ 4-3 line emission, could trace the water snow line. The anticipated water snow line is more extended than what expected from the current luminosity, attesting to bygone outburst events. - Facilitator
- -Name：Patricio Sanhueza
- Comment
- English.
Coffee will be served 20 min before the seminar.
10月9日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- October 9th, 2019, 10:30 -12:00
- Place
- Lecture Room
- Speaker
- Masaki Yoshida
- Affiliation
- SOKENDAI 5th year (D3)(Supervisor: Yoshinori Suematsu, Hara Hirohisa, Ryohko Ishikawa)
- Title
- The Chromospheric Dynamics Revealed by Lyman-Alpha Spectro-Polarimeter
- Facilitator
- -Name： Kei Ito
10月11日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 11 October (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Haruka Washinoue
- Affiliation
- The University of Tokyo
- Title
- Heating of Coronal Loops in Zero/Low-Metal Low-Mass Stars
- Abstract
-
Recent cosmological simulations indicate the existence of low-mass first stars in the current universe, although they have not been discovered yet. In order to understand the properties of the atmosphere of low-mass first stars from theoretical side, we performed one-dimensional magnetohydrodynamics (MHD) simulations for the heating of coronal loops with various metallicities.
All the simulated loops are heated up to around 10^6 K by the dissipation of Alfven waves, however, the behavior of the dynamical evolution and the physical properties of the loops are quite different for the different metallicity cases. We find that lower-metal stars have hotter and denser corona because of the inefficient radiative cooling. In particular, the density of metal-free corona is more than an order of magnitude higher than that of the solar-metal case. As a result, the UV and X-ray luminosities from the metal-free corona tend to be larger than those of the solar-metal corona, which indicates the observability of low-mass first stars and that their EUV and soft X-ray radiation could contribute to the structure formation in the early universe if a sufficient number of low-mass zero-metal stars were formed. - Facilitator
- -Name：Munehito Shoda