HISAKI Project Team
Profile Information
- Affiliation
- JSPS Fellowship for Young Scientists (PD), Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- Contact information
- suzuki.yudai
jaxa.jp - Other name(s) (e.g. nickname)
- Rye
- ORCID ID
https://orcid.org/0000-0001-6322-3402- J-GLOBAL ID
- 202301013487724451
- researchmap Member ID
- R000059491
- External link
Research Interests
4Research Areas
1Research History
7-
May, 2023 - Dec, 2023
Education
4-
Apr, 2016 - Mar, 2018
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Apr, 2014 - Mar, 2016
Awards
3Major Papers
21-
Mg Exosphere of Mercury Observed by PHEBUS Onboard BepiColombo During Its Second and Third Swing‐BysJournal of Geophysical Research: Planets, 129 e2024JE008524, Oct 16, 2024 Peer-reviewedLead authorCorresponding author
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Earth, Planets and Space, 75(1) 174, Nov 20, 2023 Peer-reviewedLead authorCorresponding authorAbstract In celestial bodies with tenuous collisionless atmospheres, such as Mercury, the spatial distribution of the exosphere is expected to reflect the surface composition. In this study, we discuss whether the distributions of Mg, Ca, and Na, the primary exospheric components of Mercury, have a local exosphere–surface correlation by analyzing the observation data of the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) and X-ray spectrometer (XRS) onboard the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. It was found that Mg has a strong local exosphere–surface correlation and Ca has a weak correlation. The Monte Carlo simulations of trajectories in the exosphere show that the weak correlation of Ca is due to the relatively large solar radiation acceleration. In addition, Na production rate in high-temperature regions is longitudinally dependent. This can be explained by considering that the weakly physisorbed Na layer on the surface is depleted under high temperature and that the distribution of strongly chemisorbed Na atoms is reflected in the exosphere. Based on these results, the conditions for components with a correlation in celestial bodies with thin atmospheres may include low volatility and low solar radiation acceleration. Graphical Abstract
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Nature Communications, 13(1), Nov 3, 2022 Peer-reviewedAbstract Dust storms on Mars play a role in transporting water from its lower to upper atmosphere, seasonally enhancing hydrogen escape. However, it remains unclear how water is diurnally transported during a dust storm and how its elements, hydrogen and oxygen, are subsequently influenced in the upper atmosphere. Here, we use multi-spacecraft and space telescope observations obtained during a major dust storm in Mars Year 33 to show that hydrogen abundance in the upper atmosphere gradually increases because of water supply above an altitude of 60 km, while oxygen abundance temporarily decreases via water ice absorption, catalytic loss, or downward transportation. Additionally, atmospheric waves modulate dust and water transportations, causing alternate oscillations of hydrogen and oxygen abundances in the upper atmosphere. If dust- and wave-driven couplings of the Martian lower and upper atmospheres are common in dust storms, with increasing escape of hydrogen, oxygen will less efficiently escape from the upper atmosphere, leading to a more oxidized atmosphere. These findings provide insights regarding Mars’ water loss history and its redox state, which are crucial for understanding the Martian habitable environment.
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Journal of Geophysical Research: Planets, 125(9), Sep 11, 2020 Peer-reviewedLead authorCorresponding authorAbstract Mercury is valuable to us because we can see the interactions between the planet and its space environment. This research aims to clarify how Mercury's neutral Na exosphere was produced. Data from MErcury Surface, Space ENvironment, GEochemistry, and Ranging/Mercury Atmospheric and Surface Composition Spectrometer (MESSENGER/MASCS) and model calculations that examine possible generation, transportation, and dissipation processes were compared. First, the seasonal variability in the amount of Na exosphere was analyzed for each local time (LT) using MASCS data. Previous research has shown that the amount of Na above LT12 reaches its maximum at the aphelion and that this maximum is recorded only at LT12. Following this result, we constructed a 3‐D Na exosphere model to understand the key seasonal variability processes occurring around LT12. The numerical calculation produced results that were consistent with the MASCS observations regarding the vertical profile and the seasonal variability at LT06 and LT18. However, the peak that occurs around the aphelion at LT12 could not be reproduced. However, the model produced results suggesting that less than 108 kg of comet stream dust particles per Mercury year could be the local and short‐term source of Na.
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Science, 364(6437), Apr 19, 2019 Peer-reviewedHayabusa2 at the asteroid Ryugu Asteroids fall to Earth in the form of meteorites, but these provide little information about their origins. The Japanese mission Hayabusa2 is designed to collect samples directly from the surface of an asteroid and return them to Earth for laboratory analysis. Three papers in this issue describe the Hayabusa2 team's study of the near-Earth carbonaceous asteroid 162173 Ryugu, at which the spacecraft arrived in June 2018 (see the Perspective by Wurm). Watanabeet al.measured the asteroid's mass, shape, and density, showing that it is a “rubble pile” of loose rocks, formed into a spinning-top shape during a prior period of rapid spin. They also identified suitable landing sites for sample collection. Kitazatoet al.used near-infrared spectroscopy to find ubiquitous hydrated minerals on the surface and compared Ryugu with known types of carbonaceous meteorite. Sugitaet al.describe Ryugu's geological features and surface colors and combined results from all three papers to constrain the asteroid's formation process. Ryugu probably formed by reaccumulation of rubble ejected by impact from a larger asteroid. These results provide necessary context to understand the samples collected by Hayabusa2, which are expected to arrive on Earth in December 2020. Science, this issue p.268, p.272, p.eaaw0422; see also p.230
Misc.
1Major Presentations
46-
PERC Int'l Symposium on Dust & Parent Bodies 2024 (IDP2024), Feb, 2024 Invited
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BepiColombo Science Working Group Meeting 2023 (BepiColombo SWT 2023), Sep 22, 2023
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Asia Oceania Geosciences Society 2023 (AOGS 2023), Jul 31, 2023
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EGU General Assembly 2023, Apr 26, 2023
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Symposium on Planetary Sciences 2023 (SPS 2023), Feb 21, 2023 Invited
Teaching Experience
5-
Oct, 2024 - Jan, 2025Earth and Planetary Physics Experiments (Vacuum Experiment) (Department of Earth and Planetary Physics, Faculty of Science, the University of Tokyo)
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Jul, 2023 - Sep, 2024Observation Exercise (The University of Tokyo)
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Jul, 2018 - Sep, 2021Observation Exercise (The University of Tokyo)
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Oct, 2019 - Jan, 2020Vacuum Experiment (The University of Tokyo)
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Apr, 2018 - Jul, 2018Computer Programming Exercise (The University of Tokyo)
Professional Memberships
3-
Sep, 2024 - Present
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Oct, 2019 - Present
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Apr, 2016 - Present
Major Works
16Research Projects
1-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2022 - Mar, 2024
Academic Activities
10-
Planning, Management, etc.Sae Aizawa, Martina Moroni, Daniel Schimid, Yudai Suzuki, May, 2024 - Present
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Planning, Management, etc.Kaori Hirata, Yudai Suzuki (zoom), May 8, 2024 - Dec, 2024participants ~ 40 people
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Panel moderator, Session chair, etc.Mar 27, 2024
