Home > 国立天文台談話会 | 太陽系小天体セミナー | 科学研究部コロキウム | 総研大コロキウム > 2022.6.20-2022.6.26


June 21 Tue 10:00~11:30 太陽系小天体セミナー Solar System Minor Body Seminar zoom

June 22 Wed 10:30~12:00 SOKENDAI Colloquium  zoom

June 22 Wed 15:30~17:00  NAOJ Science Colloquium zoom

June 24 Fri  16:00~17:00  談話会 NAOJ Seminar    zoom







Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:June 22nd, 2022 10:30-12:00

Speaker 1: Chanoul Seo
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Yuka Fujii, Hideko Nomura, Masahiro Ikoma)
Title: Atmospheres of sub-Neptune-sized exoplanets in contact with magma ocean

Speaker 2: Kousuke Ishihara
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Masao Saito, Fumitaka Nakamura, Patricio Sanhueza)
Title: Study of the fragmentation scale in high-mass star-forming regions

-Name:Matsuda, Graduate Student Affairs Unit


Seminar:NAOJ Science Colloquium
Regularly Scheduled/Sporadic:Every Wednesday
Date and time:2022 June 22, 15:30-17:00

Speaker:Chris Irwin
Title:Aspherical Shock Breakout
Abstract:The first light that emerges from a supernova is the shock breakout emission, which in the spherical case is characterized by a brief UV flash. In the case of an axisymmetric, prolate explosion, the shock first breaches the surface along the symmetry axis, then marches towards the equator; the resulting breakout light curve may differ substantially from the spherically symmetric case. We study the properties of the bolometric light curve associated with the emergence of a non-relativistic, bipolar shock from a spherical star, and identify four possible classes of breakout light curves, depending on the degree of asphericity. Compared to spherical breakouts, we find that significantly aspherical breakouts are distinguished by 1) a longer and fainter initial breakout flash and 2) an extended phase of slowly-declining emission which is produced as ejecta flung sideways during the breakout expand and cool. We show that, even when allowing for asphericity, the duration of the breakout flash cannot exceed roughly ∼R_∗/v_{bo}, where R_∗ is the stellar radius and v_{bo} is the velocity of the fastest-moving ejecta. Applying this result, we find that the long duration of the X-ray flash seen in SN 2008D cannot be explained as an aspherical breakout from a standard Wolf-Rayet star, and the same is true for the prompt X-ray emission associated with low-luminosity GRBs such as GRB 060218. We therefore suggest that these events originate from non-standard progenitors with larger radii.

-Name:Akimasa Kataoka


Seminar:NAOJ Seminar
Regularly Scheduled/Sporadic:Every Friday
Date and time:2022 June 24, 16:00-17:00
Speaker:Currie, Thayne
Affiliation:国立天文台 ハワイ観測所 / Subaru Telescope, NAOJ
Title:Directly Imaging Extrasolar Planets with the Subaru Coronagraphic Extreme Adaptive Optics Project
Direct imaging is the means by which we will eventually identify and characterize an Earth twin around a Sun-like star. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) project on the Subaru telescope is pushing the frontiers of what is possible with ground-based high-contrast imaging of extrasolar planets. In this talk, I describe key innovations in SCExAO’s wavefront sensing and coronagraphy that yield breakthrough planet detection capabilities. SCExAO is coupled to a near-infrared integral field spectrograph — CHARIS — that yields crucial information about exoplanet atmospheres. I highlight multiple newly-discovered exoplanets around nearby stars drawn from our science program that provide a new understanding on how planets form and evolve. Finally, I describe how SCExAO is a critical pathfinder for imaging the nearest Earth-like planets with upcoming ground-based extremely large telescopes.

-Name: 青木 和光 / Aoki, Wako

Home > 国立天文台談話会 | 太陽系小天体セミナー | 科学研究部コロキウム | 総研大コロキウム > 2022.6.20-2022.6.26

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