May 9 Tue 10:00-11:30 太陽系小天体セミナー Zoom
May 10 Wed 10:30-12:00 SOKENDAI Colloquium Zoom / the large seminar room (hybrid)
May 10 Wed 15:30-17:00 NAOJ Science Colloquium Zoom / the large seminar room (hybrid)
May 12 Fri 16:00-17:00 NAOJ Seminar Zoom
詳細は下記からご覧ください。
=============== May 9 Tue===============
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9日（火曜日）10時00分～11時30分
場所：zoom
講演者：藤井大地
世話人の連絡先
名前：渡部潤一
=============== May 10 Wed===============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：May 10, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker: Ko Hosokawa
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Takayuki Kotani, Yosuke Minowa, Yuka Fujii)
Title: What does the giant exoplanet atmosphere look like in the detailed spectra? Review of Measuring High-resolution Spectra of H2 Dominated Gas
Speaker : Yui Kasagi
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Takayuki Kotani, Saeko Hayashi, Wako Aoki)
Title: Exploring Brown Dwarf Atmospheres through Retrieval Analysis of High-Resolution Spectra
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== May 10 Wed===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2023 May 10, 15:30-17:00
Place：zoom / the large seminar room (hybrid)
Speaker：Tadahiro Kimura
Affiliation：NAOJ
Title：Planetary population synthesis model for validation of planet
formation theory
Abstract：
Exoplanet exploration has discovered more than 5000 exoplanets and
revealed statistical characteristics of their distribution. These
observed distributions are key to validating current theories and
advancing our understanding of planet formation processes. For this
purpose, we need a model that combines all known formation processes and
predicts the current distribution of exoplanets. We have developed a new
such model called the planetary population synthesis model and
statistically compared its predictions with observed exoplanet
distributions. The model deals in detail with the formation and
evolution of primordial atmospheres, and by using analytical or
empirical models for each elementary process, it can predict observables
such as planetary mass, radius and orbital period at a quite low
computational cost. This allows comparisons to be made with observations
for many model parameter sets. In this study we focus on the
distribution of radii and orbital periods of so-called ‘super-Earths’
and ‘sub-Neptunes’ with radii of about 1-4 Earth radii, and investigate
whether the observed distribution can be explained within the framework
of our model. The results show that the distribution can be reproduced
by changing the distribution of initial planetesimals, the disk gas
viscosity and the composition of the primordial atmosphere in
particular. We predict that both super-Earths and sub-Neptunes have
rocky solid cores, and that sub-Neptunes retain their primordial
atmospheres enriched with water vapour to this day. These predictions
are expected to be verified by future observations of exoplanet atmospheres.
Facilitator
-Name：Yuka Fujii
-Comment：English
=============== May 12 Fri===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regularly Scheduled
Date and time：2023 May 12, 16:00-17:00
Place： Zoom
Speaker:Hiroki Harakawa
Affiliation：Subaru Telescope NAOJ
Title：Understanding Galactic Circumnuclear Environments in M31 and M81 with Multi-wavelength, High-definition Observations
Abstract：The search for earth-like planets in various stellar types is crucial
since it will provide not only the essential physical information
(e.g., Mass, age, orbital distance) to understand a planet formation
process but also target candidates for future surveys for evidence of
extraterrestrial life with 30-meter class telescopes. The IRD
(InfraRed Doppler) was developed to search for exoplanets around
late-type stars with the Subaru Telescope, and the Subaru Strategic
Program (IRD-SSP) for a systematic exoplanet survey around late M-type
stars is ongoing.
As the first exoplanet discovery from the IRD-SSP, we report the
near-infrared radial-velocity (RV) confirmation of a super-Earth on a
10.77-day orbit around the M4.5 dwarf Ross 508 (Harakawa et al.,
2022). Using precision RVs derived from the IRD, we have unveiled a
semi-amplitude of 3.92 m/s, corresponding to a planet with a minimum
mass m sin i = 4.00 M_Earth. We find no evidence of stellar
chromospheric activity from our analyses of spectroscopy and
photometry.
Ross 508 b has a semimajor-axis of 0.05366 au, which gives
orbit-averaged insolation of ~1.4 times the Earth’s value, placing
Ross 508 b near the inner edge of its star’s habitable zone. Our
discovery demonstrates that the near-infrared RV search can be crucial
in finding a low-mass planet around cool-M dwarfs like Ross 508.
Facilitator
-Name：Ozaki, Shinobu