観測ロケットを用いた微小重力実験から探る宇宙ダストの核生成

木村　勇気 氏
北海道大学低温科学研究所

本講演では、小規模計画「DUST」の成果について報告する。本計画は、晩期型巨星の星周環境における宇宙ダストの核生成過程を素過程から解明することを目的とし、JAXA、NASA、DLRの国際協力のもと海外の観測ロケットを用いた微小重力実験を行うことで推進してきた。微小重力環境下では密度差対流が抑制されるため、熱流体的な揺らぎの少ない理想的な場でダストの核生成過程を再現した均質核生成実験が可能となる。さらに、海外の観測ロケットでは、実験装置に加えて生成試料の回収も可能で、実験室で詳細な分析も行うことができた。これまでの解析から、宇宙ダストの形成初期過程においても、現在結晶成長分野で話題の非古典的な核生成過程や多段階の核生成過程が重要な役割を果たしていることが明確になった。本発表では、これらの実験的証拠に基づき、従来の古典論の枠組みを超えた新たなダスト形成モデルについて議論する。

研究・管理棟（A棟）2階 会議場（1236，1237）， zoom開催

CC-CTP 機械式冷凍機

山崎　典子 氏
宇宙科学研究所　宇宙物理学研究系

CC-CTP研究開発プロジェクトチームでは，JAXAの機械式冷凍機による1K/4KのJoule-Thomson(JT)冷凍機とヨーロッパの冷却系を組み合わせて50mKを実現する実験を，2017-2018年にフランスグルノーブルで行った。1KJT冷凍機により，19mWの冷凍能力@1.77Kを達成したこと，国際共同の冷却系としてほぼ一発で50mK達成にこぎ着けたことなどが成果として挙げられる。JT冷凍機の寿命律速原因の解明と改良を行い，その成果は現在技術のフロントローディング，そしてLiteBIRDへと繋がっている。チームの終了にあたり，ヨーロッパでの共同実験経験などを中心にふりかえりを行い，今後への参考としたい。

研究・管理棟（新A棟）2階 A会議室（1257）,　Zoom開催

Detector Technology for NASA's Habitable Worlds Observatory

Dr. Don Figer
College of Science at Rochester Institute of Technology

NASA's Habitable World Observatory (HWO) will observe faint sources in ultralow (photon-per-hour) backgrounds. In this talk, we present NASA-funded research to advance single-photon counting and radiation-tolerant CMOS detectors for NASA missions, in particular, those requiring optical/UV photon counting detectors. In the project, we will measure the performance of Fairchild Imaging large-format single photon counting and photon number resolving CMOS imaging detectors (HWK4123) before and after radiation that simulates the environment at L2. These detectors have very low capacitance sense nodes to produce a large voltage response to a single photon. In a predecessor project, we found that performance for a similar detector (QIS, Gigajot Technologies) is little-changed after exposure to 50 krad(Si). The dark current can be set to beginning-of-life levels with modest additional cooling, 4-6 K for an 11-year mission. The project seeks to minimize the transient and long-term effects of radiation in NASA missions and also to design a single photon counting and photon number resolving NIR detector with similar architecture.

Conference Room A (1257) (2nd floor/ New Building A),　Via Zoom

1) JPL's Astrophysics History and Ambitions
2) Planet formation studies with JWST

1)
Dr. Jason Rhodes
Jet Propulsion Laboratory

2)
Dr. Klaus Pontoppidan
Jet Propulsion Laboratory

1) I will discuss JPL's history as an astrophysics mission implementation center and JPL's ambitions for the future in this area. Starting in the 1990s, JPL made a Pushto become a key player in NASA astrophysics mission development. Over the past 30 years JPL has led or partnered on key missions including HST, Spitzer, JWST, Planck, NuStar, WISE, SPHERex, Roman, ARIEL, and Euclid. This has been made possible by key investments in several technologies, including detectors for CMB, IR, and UV observations, wavefront sensing and control, and starlight suppression. JPL has ambitions for future missions that include PRIMA and the ambitious Habitable Worlds Observatory, in some cases with JPL leading and in others with JPL as a critical partner. JPL is also seeking to chart the path forward for future discovery in key areas defined as 'Transformational Science Challenges (TSCs).' These TSCs include understanding the history of planet formation, the search for life and habitability, and understanding dark energy, dark matter, and cosmic inflation. Addressing these challenges will require creating and sustaining partnerships with agencies around the world.

2) It is evident that the bulk chemical composition of exoplanets is intimately linked to their birth environment. However, it remains an open question to which degree exoplanetary atmospheric chemistry retains direct signatures of the bulk composition of planetary regions, for instance in terms of elemental ratios of carbon and oxygen. Our understanding of the physics and chemistry of planet-forming regions in the inner parts of protoplanetary disks is currently undergoing a revolution due to the incredible spectroscopic data returned from JWST-MIRI and NIRSpec. JWST surveys have now targeted hundreds of planet-forming disks, and a new understanding of the physics and chemistry of planet formation is emerging. I will provide an overview of recent results and discuss how these are driving the science cases of future infrared space telescopes, including PRIMA.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom

Explore2040 - The European Exploration Strategy

Dr. Angelique Van Ombergen
European Space Agency (ESA), Directorate of Human and Robotic Exploration

Dr. Gerhard Kminek
European Space Agency (ESA), Directorate of Human and Robotic Exploration

ESA's Explore2040 is a refined European exploration strategy. At the core of the strategy is a bold vision to establish continuous, sustainable, and responsible human and robotic exploration of the Solar System by providing unique contributions and benefiting society. Explore2040 firmly asserts science, the economy, cooperation, and inspiration as primary strategic drivers for Europe's continued exploration efforts. The refined strategy puts exploration into a wider perspective, serving ESA's 2040 vision and underlying the close links between space transportation, critical space-based infrastructure and related terrestrial applications and science. In this talk we will present Explore2040 and provide examples of on-going and future efforts to implement the strategy.

Conference Room A (1257) (2nd floor/ New Building A),　Via Zoom

The Search for Habitable Exoplanets: From the James Webb Space Telescope to the future Habitable Worlds Observatory

Dr. Kevin France
Laboratory for Atmospheric and Space Physics, Department of Astrophysical and Planetary Sciences, University of Colorado at Boulder

The discovery of thousands of planets orbiting stars beyond the solar system has fundamentally shifted our view of Earth's place in the Universe, has captivated the public imagination, and has transformed research priorities in astrophysics. We are now actively searching for atmospheres on temperate, terrestrial planets, and are developing the technical tools to find and characterize "Earth-2.0". The goal of understanding the frequency and diversity of habitable (and inhabited) planets requires multiple techniques for exoplanetary observation and a detailed understanding of the evolving stellar environments in which they live.

In this talk, I will present an overview of the multiple paths in our search for inhabited planets, from current efforts to find temperate planets with stable atmospheres around red dwarf stars with the James Webb Space Telescope (JWST) to future detection of true Earth-Sun analogs with NASA's upcoming Habitable Worlds Observatory (HWO). I will summarize recent progress and open questions in understanding the key parameters that influence exoplanet atmospheres, focusing on results from JWST and observational and experimental work at ultraviolet wavelengths to characterize the stellar photons and coronal mass ejections that shape rocky planets. I will then present an overview of the upcoming HWO mission, current opportunities for international collaboration with the mission development, and the path to launch in the ~2040 timeframe.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom

Low frequency Gravitational Wave Astronomy

Dr. Karsten Danzmann
Max Planck Institute for Gravitational Physics (AEI) Hannover / Leibniz Universität Hannover

For thousands of years, humanity has observed the universe with light. Since the first direct detection of gravitational waves on September 14, 2015, ten years ago, our view of the cosmos has fundamentally changed. Gravitational wave astronomy on Earth has now become routine. The next step is to open the low frequency window with laser interferometers in space. For more than 30 years, we have been developing the LISA mission. In January 2024, LISA was officially adopted by ESA, and we are now in Phase B2. With the selection of the industrial prime, the mission is progressing steadily toward its launch in 2035, bringing us ever closer to listening to the gravitational-wave universe from space.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom

Imaging and Design with Differentiable Physics Models

Dr. Benjamin Pope
Macquarie University

The technology that underpins machine learning - differentiable programming - is poised to revolutionise astronomy, making it possible for the first time to fit very high dimensional models: hierarchical models describing many objects; the sensitivity of millions of pixels in a detector; models of images or spectra with very many free parameters; or neural networks that represent physics we cannot easily solve in closed form. It also enables fundamental information-theoretic quantities like the Fisher information to be calculated, allowing for determination and optimization of the information content of an experiment. I will discuss how we apply this to the James Webb interferometer experiment, to provide a data-driven self-calibration of the telescope's highest resolution mode and its difficult systematics; to design the Toliman Space Telescope to do high-precision, distortion-tolerant astrometry; and give an overview of related work on interferometry, transits and AGN reverberation mapping in our group.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom

Unraveling plasma physics of spacecraft electric propulsion systems

Dr. Kentaro HARA
Stanford University, Aeronautics and Astronautics

Spacecraft electric propulsion (EP) systems have become an essential tool for space exploration and utilization. Propulsion devices with high thrust, high specific impulse, high efficiency, and long lifetime help enable current and future space missions. Electrical power, typically collected from solar panels, is used to energize and ionize propellant to generate thrust. Despite the success of EP systems, predictive modeling of ionized gases, i.e., plasmas, remains challenging due to the coupling between collisional-radiative processes, plasma-wall interaction, circuit-plasma coupling, and plasma instabilities and turbulence. In this seminar, I will introduce the state-of-the-art EP technologies and the plasma physics problems associated with EP systems. I will then discuss recent advancements in the physics-based and data-driven models, including fluid moment approaches, particle-in-cell Monte Carlo collision models, and data assimilation using extended and ensemble Kalman filters.

Conference Room A (1257) (2nd floor/ New Building A),　Via Zoom

Revealing the Core of the Milky Way through Japanese Infrared Astronomy Projects

Dr. Shogo Nishiyama
Miyagi University of Education

The center of the Milky Way Galaxy is an area of great interest not only in astronomy, but also in the fields of physics and advanced science and technology. It holds clues to the Milky Way's formation and evolution history, and continues to be a site where new stars and star clusters are born. It is not only the stage for the discovery of a supermassive black hole, but also a testing ground for theories of gravity, including general relativity. Such research has been made possible by cutting-edge technologies such as infrared detectors, adaptive optics, and optical-infrared interferometry. In this talk, I will present the current picture of the Galactic center that has emerged from past studies. In addition, extensive observational projects are underway. Among these, the collaboration between JASMINE and Subaru will provide a more detailed and extensive view of the center of Milky Way.

Conference Hall (2nd floor/ Research and Administration Building A),　Via Zoom