ABSTRACT. As the 1990s saw the inauguration of 10m class telescopes, the 2030s will bring on the era of 30m-class telescopes. As Vice Chair of the GMT Board this talk will skew towards the Giant Magellan Telescope, but I will overview the 3 planned ELTs and their current state, and go through their planned instrumentation with a focus on the science potential each of these bring, focusing on the complementarity of the 3 observatories.

ABSTRACT. TBA

ABSTRACT. Aspheric mirrors are the core components that determine the performance of optical telescope systems. Silicon carbide ceramic is the best candidate material for large lightweight mirrors because of its excellent mechanical properties. However, due to the high hardness of the silicon carbide material, it is extremely difficult to process. Therefore, effective optical manufacturing and testing processes are crucial to realize the rapid and high-precision fabrication of large-aperture SiC aspheric mirrors. This paper focuses on the manufacturing process of 2–4 m SiC aspheric mirrors, including profile testing technology, computer-generated hologram optical testing technology, computer controlled optical surfacing and magnetorheological finishing technology. The application strategies of those technologies in the high-precision manufacturing process of large-aperture aspheric mirrors are explained in detail, and the difficulties and corresponding solutions are analyzed. Also, the latest advances in robotic optical manufacturing technology are presented. In addition, the practical applications of these optical manufacturing and testing technologies for large aspheric optics are introduced. Finally, an outlook is provided for the manufacturing of large-aperture or super-large-aperture aspheric optical elements.

ABSTRACT. Modern Korean astronomy started over with the procurement of the 61cm optical telescope at Sobaeksan Observatory(SOAO) in 1960’s. This foundation led to a significant leap with the establishment of the Bohyunsan Optical Astronomy Observatory (BOAO) and its 1.8m telescope, which remains a cornerstone of domestic research.

The evolution of Korean ground-based optical astronomy is further highlighted by the deployment of the Korea Microlensing Telescope Network (KMTNet) and active participation in the Giant Magellan Telescope (GMT) project. As of 2026, an in-depth analysis explores the strategic positioning of Korean optical astronomy, particularly as it navigates the complex shifts in international relations and global scientific cooperation.

ABSTRACT. Subaru Telescope uniquely features wide field imaging and spectrograph instruments at its prime focus. Others include the stable and spacious Nasmyth platform where experimental observing instruments can be tested such as exoplanets imagers and spectrographs. In this talk, current status of Subaru Telescope will be given as well as the future plans.

ABSTRACT. Thailand has involved in the “International Lunar Research Station (ILRS)” program since 2023. On September 25,2023, NARIT under the Ministry of Higher Education, Science, Research and Innovation has signed an MoU with the Deep Space Exploration Laboratory (DSEL) under the China National Space Administration (CNSA), chaired by HRH Princess Maha Chakri Sirindhorn, for Thailand-China collaboration on the ILRS initiative. In April 2024, Thailand made an official application to join the ILRS, and the application was finally approved by the CNSA. Under the ILRS involvement, NARIT, in partnership with Mahidol University, Bangkok, Thailand has submitted a proposal to CNSA for the development of a space scientific research payload for the Chang’e-7 orbiter namely, “Moon Aiming Thai-China Hodoscope (MATCH)” to detect high energy electrons, protons and alpha particles under cosmic radiation conditions in space in Lunar orbit and its impact between Moon and Earth environment. Since 2024, under collaboration between Thai scientists and engineers in partnership with Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) joined the design and fabrication of MATCH. In 2025, CNSA has approved engineering and flight models of MATCH and ready to be integrated to Chang’e 7 spacecraft which is planned to be launched in 2026. Integrating science and engineering through the involvement through the deep knowledge of ILRS program will be one of the key strategies to leverage significantly sustainability human capacity building for future space and technology development in Thailand.

ABSTRACT. I review the recent progress in studying gamma-ray bursts (GRBs), fast X-ray transients (FXTs), and fast radio bursts (FRBs) within the context of multi-wavelength (MW) and multi-messenger (MM) transient astrophysics. Special attention is paid to the breakthrough observations made with the Einstein Probe, SVOM space telescopes, and the FAST radio telescope. Current understanding and open questions in these areas will be highlighted, with a discussion of the prospects of making further progress in the upcoming decade.

ABSTRACT. We reveal several new properties of the Kerr black hole previously unexplored in the Hawking era. These results provide new insights into the structure of black holes and future perspectives on astrophysical phenomena.

1. The Horizon Mass Theorem states that for all black holes: neutral, charged, or rotating; the mass observed at the event horizon is always twice the irreducible mass observed at infinity. The irreducible mass does not contain rotational energy, therefore there is no rotational energy inside a rotating black hole.

2. The rotational energy of the Kerr black hole exists completely outside the horizon. Accordingly, the extraction of rotational energy in the Penrose process occurs in the ergosphere region.

3. A black hole with an angular momentum and an angular velocity has a moment of inertia and a radius of gyration lying outside the horizon. When the rotation stops in an energy extraction process, there exists an irreducible moment of inertia for the static black hole. A Schwarzschild black hole does not have this property.

4. All black holes have the same surface area if their irreducible masses are equal in value, independent of their types: static, charged, or rotating. This is the Area Universality Law. It shows that the entropy of a black hole does not depend on its rotational or electrostatic energy. Black hole entropy has a purely gravitational origin.

These surprising properties show that the Kerr black hole has an extended structure. They would clarify the real nature of black holes, in particular, the supermassive black holes at the centers of galaxies.

References: Y. K. Ha, Int. J. Mod. Phys. D, Vol. 31, No. 4 (2022) 22300006 The Irreducible Mass of Christodoulou-Ruffini-Hawking Mass Formula

Y. K. Ha, Int. J. Modern Phys. D (2026) 2540019 A New Structure of Black Holes

Author is four-time winner of Gravity Research Foundation Award

ABSTRACT. In this talk, I will show our recent statistical study of broad-lined Type Ic supernovae (SNe Ic-BL), which includes 69 GRB-unassociated and 11 GRB-associated events. Using a magnetar central engine to model the early-time peak emission and 56Ni decay for the late-time tail, our model successfully reproduces the multi-band light curves of these SNe. We find that the initial spin period of magnetars in SNe Ic-BL may range from∼ 1 to 5ms, with magnetic field strengths between∼ 10^{15} and 10^{16}G. Importantly, we did not observe any statistically significant differences between GRB-associated and GRB-unassociated SNe Ic-BL. By fitting the inferred explosion energies and ejecta masses of SNe Ic-BL and comparing them with other superluminous SNe Ic (SLSNe Ic) and fast blue optical transients (FBOTs), we identified a universal relationship, suggesting a common origin. We confirmed this universal relationship using binary star evolution models, supporting the idea that SNe Ic-BL, SLSNe, and FBOTs may originate from a tidal scenario. Additionally, we found that SNe Ic-BL share similar ejecta and 56Ni production properties with normal SNe Ic, implying that their main difference likely lies in whether their progenitors retain high rotation rates, enabling the formation of rapidly spinning magnetars that influence the explosion energetics. Based on these findings, we propose a unified model for these stripped-envelope SNe.

ABSTRACT. Large-scale magnetic field is believed to play a key role in launching and collimating jets/outflows. It was found that advection of the external field by a geometrically thin disk is rather inefficient, while the external weak field may be dragged inwards by fast radially moving tenuous and/or hot gas above the thin disk. We investigate the field advection in black hole accretion systems (thin disk with outflow, thin disk covered by hot corona, and advection-dominated accretion disk ). For the case of a thin disk, due to the presence of the magnetically driven outflow, which carries away most of the angular momentum of the disk, the radial accretion velocity of the thin disk increases a lot, and the magnetic field is efficiently transported inward; For a thin disk covered with hot corona, in which turbulence is responsible for the angular momentum transfer of the gas. The radial velocity of the gas in the corona is significantly higher than that in the thin disk. The external magnetic flux is efficiently transported inwards by the corona; For the case of ADAF, the external magnetic flux can be efficiently transported inward to form an inner magnetically arrested disk. Then we investigate the dynamical structure of the outflows driven by the large-scale magnetic field. With the derived large-scale magnetic field, the outflow solution along every field line is obtained by solving a set of magneto-hydrodynamic equations self-consistently with boundary conditions. We find that the terminal speeds of the outflows driven from the inner region of the disk are ∼0.01–0.8c. The properties of the magnetic outflows derived in this work are roughly consistent with the fast and or ultra-fast outflows detected in some active galactic nuclei and X-ray binaries (XRBs). The velocity, temperature, and density of the outflows derived in our work can be used for calculating the emergent spectra and their polarization of the accretion disk/corona/outflow systems. Our results may help understand the features of the observed spectra of XRBs and active galactic nuclei.

ABSTRACT. In the era of `Precision Cosmology'remarkable advances have been made in the determination of cosmological parameters from the Cosmic Microwave Background and Big Bang Nucleosynthesis, with spectacular concordance between these two pillars of the Standard Cosmological Model. While much exposure has been given to the impressive results from the Planck mission and recent CMB experiments that have built on Planck's success, perhaps less attention has been paid to the equally striking advances made in the last ten years in the measurements of the abundances of the light elements forged in the first few minutes of our Universe's history. In this talk, I shall focus in particular on the determination of the primordial abundance of deuterium, in an overview that spans almost 80 years, from the first seeds of the idea sown in the 1940s to the most recent results and forward look to the era of Extremely Large Telescopes and next generation Wide Field Surveys of the sky.

ABSTRACT. The James Webb Space Telescope (JWST) has revolutionised our understanding of the first billion years of cosmic history. I will present an overview of these discoveries with a focus on the 3 things I consider the most important: (1) the discovery of an over-abundant population of luminous star forming galaxies at z>10, (2) the discovery of a population of extremely weird early super-massive black holes at z>4. and (3) the too-early production of a population of massive quiescent galaxies. I will review these discoveries and possible connections between them and how JWST can make future observations to resolve the issues of early galaxy formation.

(Note this is an invited talk)

ABSTRACT. In recent years, China has launched and operated several space astronomy missions such as Wukong, POLAR, Insight-HXMT, GECAM, Einstein Probe (EP), and SVOM, embarking on a journey to explore the extreme universe. Nevertheless, numerous key scientific questions about the extreme universe remain to be solved. These include problems related to extreme explosions, extreme origin, extreme energy, extreme celestial objects, extreme gravity, extreme density, and extreme magnetic fields. In the next 5-15 years, we plan to address and solve these questions through several internationally leading large-scale space high-energy astrophysics missions. These include the "Gamma-ray Burst Polarimeter-II" (POLAR-2) and the "High Energy cosmic-Radiation Detection" (HERD) experiment, to be operated on China's space station; the enhanced X-ray Timing and Polarimetry (eXTP) space observatory; and the "Chasing All Transients Constellation Hunters" (CATCH) plan, consisting of hundreds of micro-satellites. These projects are poised to bring revolutionary advancements to the in-depth exploration of the extreme universe.

ABSTRACT. To reproduce observed galaxy properties, cosmological simulations require that massive galaxies experience feedback from active galactic nucleus, which regulates star formation within those galaxies. However, constraining the energetics and timescales of these feedback processes has been challenging due partially to the multi-scale, multiphase nature of the impacted gaseous medium. In this talk, I will present results from our recently accepted Science paper that reports the discovery of a galactic-scale outflow driven by a precessing, low-power radio jet in an early-merger, active disc galaxy VV 340a. Through a study combining optical, infrared, submillimeter and radio observations, we report the first observation of a S-shaped kiloparsec jet driving massive super-heated gas in an outflow, the most extended and coherent of coronal gas structures known to date. Our multi-faceted analysis demonstrated the radio jet as the origin of the galactic-scale outflows, and that the outflow is substantially reducing the gas depletion timescale. The star formation history of VV 340a reflects the likely impact of AGN feedback from the radio jet. This pilot study showcases our larger observational campaign of nearby active galaxies designed to address key AGN feedback topics in the galaxy’s lifetime where black hole activities are expected to peak.

ABSTRACT. Hot gas giants rotating in close orbits form a distinct subclass among a very diverse population of exoplanets. They have a unique feature of extensive outflow of the upper atmosphere. Observational evidence for such atmospheric outflow has been found for a number of hot Jupiters and warm Neptunes by measuring their transit absorption in the VUV lines in the era of the Hubble Space Telescope.

At the same time the JWST is delivering a treasure trove of information on the lower atmosphere of exoplanets, revealing molecules and organic compounds. Complex chemical retrieval models are being developed to interpret the transit absorption spectra. It is increasingly urgent to develop unified models combining lower and upper atmosphere and exosphere to be able to interpret multi-line observations and extract unique information.

Recent studies of ultra-hot Jupiters revealed that accurately calculating the heating/cooling balance of atmosphere and the line absorptions requirefull NLTE simulation of kinetics of excited levels of elements. For a number of ultra-hot Jupiters, it was shown that the observed absorption in the Hα line is directly related to a new channel of atmospheric heating – photoionization of excited levels by VUV and NUV photons. This significantly rises thecomplexity of models (Shaikhislamov et al. 2025).

Another fundamentally important aspect of exoplanetary research is planetary magnetism. A sufficiently strong magnetic field radically alters the structure of upper atmosphere and its interaction with the stellar plasma. The challenge is the total lack, so far, of viable means to constrain it through any kind of observations. In a recent paper (Rumenskikh et al. 2025) wedescribed an essentially novel way to relate a planetary magnetic field with the transit absorptions in multiplet lines via the quantum atomic alignment effect.

Observations with the Kepler and TESS space telescopes not only detected numerous exoplanets but made a far-reaching discovery of super-flares. The correlation between flare energy and CMEs shows a monotonic pattern for the Sun, but does not allow extrapolation to superflares. A new method for obtaining quantitative measurements of CME parameters through transit observations of the response of hot exoplanet atmospheres to the extreme activity of their host stars was proposed (Shematovich et al.2023). To this end, we are developing a program of observations on the upcoming Russian space telescope Spektr-UF (WSO-UV), which will continue the scientific legacy of Hubble.

Finally, the search for biosignatures in exoplanet atmospheres is among the most inspiring scientific frontiers. N₂–O₂-dominated atmospheres may hint at biological activity, with NO as a key indicator. Calculations show that absorption by NO could be observed in UV spectra with WSO-UV on Earth-type planets orbiting active stars within 30 pc (Tsurikov et al. 2024).

The research is supported by RNF projects 23-72-10060, 25-72-20053.

ABSTRACT. Exoplanet research in Thailand began approximately a decade ago and has since expanded to cover a comprehensive range of detection techniques, including transit, radial velocity, gravitational microlensing, and direct imaging. This work proceeds through both observational campaigns and instrumentation development.

For transits, we utilize NARIT’s telescopes combined with space-based data to study planetary physical parameters, transit timing variations (TTVs), exomoons, and atmospheres via transmission spectroscopy. We are members of the Spectroscopy and Photometry of Exoplanet Atmospheres Research Network (SPEARNET), a collaboration involving Thailand, the UK, Taiwan, and India. SPEARNET conducts long-term statistical studies of hot transiting exoplanet atmospheres using a globally distributed optical-infrared network. To maximize observational efficiency, we have characterized a specialized target-telescope matching metric and developed a novel transit fitting code designed for multi-wavelength, multi-epoch datasets.

For microlensing, we conduct follow-up campaigns using the Thai Robotic Telescope Network. While traditional surveys (e.g., OGLE, KMTNet) focus on the Galactic bulge, we collaborate with the Black Hole Target and Observation Manager (BHTOM) and ESA’s Gaia mission to identify and monitor candidates across the entire sky, particularly in the Galactic disc. Additionally, we utilize the Manchester-Besancon Microlensing Simulator (MaBulS) to model event rates. This simulation work extends to investigating the "Earth Microlensing Zone," analyzing how frequently Earth might be detected by extraterrestrial civilizations via photometric microlensing against the Sun.

Finally, we highlight two major instrumental developments at NARIT for the 2.4-meter Thai National Telescope (TNT). The first is EXOhSPEC, a newly commissioned fiber-fed, high-resolution spectrograph (R=70,000). Utilizing a prism-grating design, it is optimized for precision radial velocity follow-up. Concurrently, we are developing the Evanescent Wave Coronagraph (EvWaCo) for high-contrast imaging. EvWaCo features an achromatic coronagraph mask with adjustable size and integrates adaptive optics directly into the system. These efforts collectively signify Thailand's growing role in the global characterization of exoplanetary systems.

ABSTRACT. The classical three-body problem has only planar Lagrangian points. With the discovery of exoplanets in non-planar orbits, we propose a scenario of their possible formation in this paper. In the case where either one of the primaries is radiating or the other is oblate, we obtain out-of-plane Lagrangian points. We calculate the location of these Out-of-plane Lagrangian Equilibrium Points (OLEPs) and study their stability for varying values of radiation pressure parameter β and oblateness parameter a. We compare our results to eighteen exoplanet systems from NASA exoplanet archives, of which only eight have out-of-plane planets. We thus explore the possibility of the OLEPs to host the seeds of out-of-plane planet formation.

ABSTRACT. Studies of exoplanetary atmospheres using transmission spectroscopy provide information on the composition and structure of exoplanetary atmospheres. Traditional retrieval techniques, such as Markov Chain Monte Carlo (MCMC) and nested sampling, are computationally demanding, often requiring hours or days to analyse a single spectrum. In this work, we employ a machine-learning approach, specifically the random forest regressor (RFR), to predict the atmospheric parameters of the hot jupiters. The RFR is trained on synthetic optical transmission spectra generated by Tau Retrieval for Exoplanets (TauREx3) and binned according to the transmission profiles of the Johnson–Cousins and Sloan Digital Sky Survey (SDSS) filters. The trained model is used to predict the planetary radius (R_p), the equilibrium temperature (T_p), and the mixing ratios of titanium oxide (X_TiO) and vanadium oxide (X_ VO). The first model can predict on the test dataset the R_p with R^2 = 0.9989. The average R^2 of T_p, X_TiO and X_VO across five models is 0.886, 0.739, and 0.821, respectively. In the benchmark test, the RFR achieves very high accuracy comparaed to TauREx3, but with a computational speed-up of approximately 400,000x compared with TauREx3 retrievals on the same dataset. A recursive feature elimination analysis reveals that as few as five filters can achieve predictive performance comparable to the full set of ten. This demonstrates the potential of the RFR model as a complementary tool for providing prior parameter estimates in real observations, particularly in cases where true parameter boundaries are uncertain or certain filters are unavailable.

ABSTRACT. TBA

ABSTRACT. China’s space science and utilization efforts are advancing along a cohesive roadmap extending from the operational China Space Station (CSS) to Manned Lunar Exploration and the development of cislunar infrastructure. The CSS has completed construction and entered its utilization phase. As the “Space Laboratory”, it offers flexible and diverse conditions with abundant experimental resources, capable of supporting thousands of scientific research and utilization projects across more than 30 research topics under four major disciplines: space life sciences and human research, microgravity physical sciences, space astronomy and Earth sciences, and new space technologies and applications.

The Technology and Engineering Center for Space Utilization (CSU), on behalf of the Chinese Academy of Sciences, leads the space utilization system of the China Manned Space Program. CSU serves as the overall entity for the space utilization system of the CSS and Manned Lunar Exploration, while also acting as the leading initiator of the DRO program under its cislunar initiatives. Building on experience from the CSS, China is progressing toward Manned Lunar Exploration, with a roadmap focused on landing, surface operations, and sustainable human presence on the Moon. To enable such missions and future deep-space endeavors, cislunar space is being developed as a strategic hub. Key to this effort is the DRO - a stable orbit serving as a versatile node connecting Earth, the Moon, and beyond. China has successfully deployed a DRO-based constellation, demonstrating low-energy transfer and reliable inter-satellite communication.

Together, the CSS, upcoming China Manned Lunar Missions, and DRO-based infrastructure form an integrated chain. This coordinated approach supports sustained exploration and facilitates international collaboration in space science and utilization.

ABSTRACT. Space is accumulating a rubbish problem of Keplerian proportions. With over 35,000 tracked debris objects and millions more untracked, low Earth orbit is approaching a tipping point — the Kessler Syndrome — where cascading collisions could render entire orbital shells unusable for generations. Yet the economic incentives to act remain stubbornly misaligned: those who litter orbit bear none of the cost, while the global space community bears all of the risk.

This talk makes the case for space debris retrieval insurance bonds as a market-based mechanism to close that loop. Updating the global policy landscape and presenting new economic modelling on bond feasibility and pricing, Professor Mainelli argues that such instruments can mobilise private capital for active debris removal at scale. Crucially, he sets out why Hong Kong — with its deep financial markets, rule-of-law heritage, and growing space ambitions — is uniquely positioned to originate, structure, and trade these instruments, becoming the orbital circular economy's financial home.

ABSTRACT. Low-frequency radio observations from Earth are severely limited by ionospheric reflection, absorption, refraction, and significant radio frequency interference (RFI). To date, no high-resolution sky map is available at frequencies below 30 MHz. Moreover, ground-based experiments within the 30–120 MHz band—which is crucial for studying cosmic evolution from the Dark Ages to the dawn of the first stars—are highly susceptible to systematic errors. We shall refer to this band as the ultralong wavelength band below. The cislunar orbit provides an excellent environment for low frequency radio observations, free from the systematic effects that hinder ground-based measurements. In this talk I will present the Hongmeng Project, also known as the Discovering the Sky at the Longest Wavelengths (DSL) mission. The project aims to deploy a constellation of satellites into a circular orbit around the Moon via a single rocket launch, forming a linear array with non-uniform spacing along the orbit. Astronomical observations will be conducted from the far side of the Moon to avoid terrestrial RFI, with data transmission to Earth occurring from the near side. The constellation includes a mother satellite responsible for onboard data processing and Earth communication, eight daughter satellites dedicated to interferometry imaging and spectral observations in the 0.1–30 MHz band, and one additional daughter satellite performing high-precision global spectral measurements in the 30–120 MHz band. These observations are expected to reveal the ultralong wavelength universe for the first time, delivering valuable data in areas such as the cosmic Dark Ages and cosmic dawn, radio galaxies and quasars, the Galactic interstellar medium, the Sun, and solar system planets. These data hold the potential to uncover new phenomena and establish the new research field of Ultralong Wavelength Astronomy.

ABSTRACT. Over a decade of operation, the benefits and potential of simultaneous multi-frequency VLBI observations with KVN have been well demonstrated. One of the key advantages is the frequency phase transfer technique, which enables an extension of the coherence time by up to two orders of magnitude compared to conventional methods. A fourth KVN station has recently been constructed, and KVN now operates as a four-element array with better calibration accuracy. Furthermore, ongoing upgrades to the KVN receiver and backend systems aim to expand the accessible frequency range even further. In this talk, I will present the current status and plans of KVN.

ABSTRACT. In this talk, I shall present the upcoming large optical-IR ground-based facilities in India, for both day-time and night-time astronomy. The government of India has announced 2 mega telescope facilities and one upgradation in the recent budget. I shall present the two mega projects, the 2-m large solar telescope proposed to be built on the banks of the Pangong-Tso lake in Ladakh with a time-line of 5 years, and the 14m class segmented telescope to be built in Hanle in Ladakh with a time-line of about a decade. I shall also present the upgradation plans for the 2-m Himalayan Chandra Telescope, located in Hanle, that has completed 25 years of operation. I shall also touch upon plans for the academia-industry connect to execute these projects.

ABSTRACT. High precision manufacturing of large aperture complex curved surface optical elements is one of the core technologies in the development of modern large-scale optical systems. Manufacturing optics depends on optical processing equipment and technology. Compared with five-axis CNC machine, industrial robots are more flexible, cost-effective and efficient. However, the motion accuracy of industrial robots limits the precision of optical manufacturing. This report will introduce the research progress of optical manufacturing technology based on industrial robots, including Abrasive-Belt Milling, Computer Controlling Optical Surfacing, Flexible Ball-end tool polishing and Magnetorheological Finishing. Some Multi-robot collaboration on large mirrors will be introduced as well. Moreover the intelligent prediction of removal function is studied for real-time control of the manufacturing process. Finally, the application of optical manufacturing equipment based on industrial robots for large aperture aspherical mirrors, is introduced and the future development is prospected.

ABSTRACT. We have developed the Optical and Infrared Synergetic Telescopes for Education and Research project (OISTER) since 2011 to construct a network of 9 universities, each of which has its own optical/infrared telescope(s), and the National Astronomical Observatory in Japan has served as the coordinator of this project. The aim of this project is to promote state-of-the-art research, mainly on time domain astronomy, by utilizing the optical and infrared observation network of small-to-mid diameter telescopes distributed over Japan and one in South Africa. We can perform simultaneous multi-wavelength and multi-mode observations of single target, including optical and infrared observations and photometric, spectroscopic, polarimetric, and spectropolarimetric observations. While we currently set the multi-messenger astronomy including follow-up observations of gravitational wave-radiation detections and neutrino events as main targets, research achievements have been given in a wide range of the field, such as supernovae, stellar flares, X-ray binaries, solar system bodies, and so on. The other aim of OISTER is education. The research field and method of students would tend to be limited within those of supervisors in their university. OISTER holds common seminars, short-term visiting training programs, workshops, data analysis schools, and so on, to broaden the scope of young researchers and improve their capabilities. In this talk, we will review the activities, results and prospects of OISTER.

ABSTRACT. A general description is given of the project Spektr–UF (former name World Space Observatory–Ultraviolet, WSO–UV). The Project Spektr–UF aimed at creating a large space observatory for operation in the UV spectral domain (115–320 nm). The Spektr–UF observatory includes a 170 cm aperture telescope capable of high-resolution spectroscopy and long slit low-resolution spectroscopy as well as high resolution imaging. The project is underway for quite a long time. Because of several factors (sanctions and withdrawal of foreign partners) the launch of the observatory has been postponed to 2031. The Russian team of the project was forced to redesign some of the observatory's instruments (most relevant is the Field Camera Unit) and replace many of the electronic ITAR components. The project is funded by the Roscosmos State Corporation as a part of the federal project Space Science. Main goal of this report is to describe the current status of the project focusing on some new touches.

ABSTRACT. Collisionless shocks are ubiquitous throughout the cosmos, operating across a vast range of environments, from the solar wind and supernova remnants to cosmological shocks associated with the large-scale structure of the universe, including galaxy clusters. While these shocks share fundamental characteristics, the underlying physical processes are profoundly influenced by the local plasma conditions, such as density, temperature, and magnetic-field strength and topology. In the high-beta plasma of the intracluster medium (ICM), where thermal pressure dominates over magnetic pressure, shock dynamics and particle acceleration operate in a regime distinct from that of lower-beta interstellar plasmas.

This talk explores the multiscale physics governing nonthermal particle production in galaxy clusters, focusing on the extraction of cosmic rays from the thermal pool and their acceleration to relativistic energies. We examine the interplay among primary mechanisms, including shock-drift acceleration, stochastic turbulence acceleration, and diffusive shock acceleration, with particular attention to the longstanding "injection problem," namely the preacceleration required to bridge thermal and relativistic regimes. We then review how these nonthermal particle populations are revealed observationally through diffuse synchrotron emission in radio halos and relics, as well as through the still-elusive gamma-ray signatures from hadronic interactions. Finally, we summarize the current observational status and open questions in studies of nonthermal emissions from galaxy clusters and outline prospects for future progress.

ABSTRACT. Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles known in the Universe, yet their origins remain unresolved. Radio galaxies (RGs), with their powerful relativistic jets, are widely regarded as promising accelerators capable of producing such extreme energies. Using studies that combine relativistic hydrodynamic simulations with Monte Carlo particle transport, we have shown that UHECRs can be energized to energies exceeding 10^20 eV through a combination of shock, turbulence, and shear accelerations in the jet-induced flows of Fanaroff-Riley type RGs. The resulting time-asymptotic UHECR spectrum is characterized by a double power law with an extended exponential cutoff, shaped primarily by relativistic shear acceleration. Adopting this spectrum, we have simulated the propagation of UHECRs from nearby RGs to evaluate the flux and composition of particles arriving at Earth. Focusing on prominent local sources such as Virgo A, Centaurus A, and Fornax A, in this talk, we present the predicted energy spectrum and mass composition of these UHECRs at Earth and compare them with observational data from the Pierre Auger Observatory and the Telescope Array experiment. We also discuss the implications of our findings for the understanding of UHECR origins and their astrophysical significance.

ABSTRACT. In this study, we investigate the structural properties of strange stars (SSs) using a modified colour-flavour-locked (CFL) equation of state (EoS) that incorporates perturbative quantum chromodynamics (QCD) correction factors. The inclusion of these corrections allows a more realistic representation of the strong interaction among quarks in ultra-dense matter. We observe that for a given QCD correction parameter $c_{cor}$ , the energy per baryon of strange quark matter, evaluated at zero external pressure, remains within the stability bound $(E<930.4~MeV/fm^3)$ only above a certain critical range of the quark chemical potential $\mu$. Furthermore, for fixed $c_{cor}$, the stability of strange matter also depends on the colour superconducting pairing gap $\Delta$, and a minimum value ($(\Delta_{min})$) is required to satisfy stability conditions, implying a correlation among $c_{cor}$, $\Delta$ and $\mu$ . Assuming spherical symmetry, we employ a Tolman-VII type metric ansatz and obtain an exact solution to the Einstein field equations coupled with the modified CFL EoS. The resulting stellar model exhibits regular behaviour of thermodynamic quantities throughout the interior and satisfies all standard energy and stability conditions. For $c_{cor}=0$, $m_s=0 ~MeV$, $\Delta=200~MeV$ and $\mu=205~MeV$, the maximum mass is found to be $3.23~M_{\odot}$. Since the maximum mass and radius depend sensitively on $c_{cor}$, $\Delta$, $\mu$ and $m_{s}$, the model can be tuned to describe compact stars consistent with recent gravitational-wave observations, including sources with masses up to $~3.23 M_{\odot}$.

ABSTRACT. After a binary black hole merges, the perturbed metric rings down to a stable Kerr spacetime. The gravitational-wave ringdown signal is emitted, and from which it is valuable to extract the physical information of the black hole. Analysis in the frequency domain and time domain exists, but with different pros and cons. In the talk, I will firstly focus on the ringdown analysis of the first gravitational-wave event, GW150914, and probe the possibility of detecting an overtone mode from real data. Then, I will present a new package, FIREFLY, that we developed recently with inspiration from F-statistic. It has the capability to accelerate the analysis by a few orders of magnitude, thus is suitable for analyzing more and more events to be received in the next-generation detectors. Finally, I will give an example of testing electromagnetically charged black holes with parametrized waveforms as well as waveforms from numerical simulations.

ABSTRACT. This paper aims to obtain similarity solutions for self-gravitating perfect gas with variable density under the effect of axial or azimuthal magnetic field in rotating medium using Lie group theoretic method and optimal classification of sub-algebras. One parameter infinitesimal group of transformation is introduced to obtain infinitesimal generators. Based on arbitrary constants present in the infinitesimal generators 5-dimensional Lie algebra has been obtained. Similarity solutions have been obtained for power law shock path and two cases of exponential law shock path. Governing set of PDEs (partial differential equations) has been transformed into set of ODEs (ordinary differential equations) using similarity transformation obtained by optimal classification of sub-algebras. Numerical solutions for set of ODEs has been obtained using Mathematica software. Effects of shock Cowling number, gravitation and rotation parameters, adiabatic index, ambient density variation index have been explored. Rotational parameter, shock Cowling number and adiabatic index have decaying effect on shock wave. Shock strength increases with an increment in gravitational parameter and change from azimuthal magnetic field to axial magnetic field. This study has its potential applications in astrophysical events such as galactic winds, supernova explosion, accretion disks. The solutions obtained here can be used to analyze the measurements made by spacecraft in the solar wind and in the vicinity of Earth’s magnetosphere.

ABSTRACT. Gamma-ray bursts (GRBs) are the universe's most energetic phenomena (~10^42 - 10^47 J) lasting for a very short duration (~ milliseconds - a few seconds). Even after an average of one GRB detected per day, their emission mechanism still remains contentious. Inferences drawn from the empirical modelling of the GRB spectrum are often inconclusive. Some studies favor the emission from a thermal blast of hot plasma, while others support a synchrotron emission originating from a rapid acceleration of particles at the expense of burst energy. Under these scenarios, the spectral width (W), which is measured at half maxima, is expected to decrease with time. We carried out a detailed procedure to redefine the Band function with W as one of the parameters, to study the GRB spectra. This model was convolved with the 3ML, and the temporal evolution of W, for the case of GRB 220426A and GRB 230812B using the Fermi/ GBM data, was investigated. We show for the GRB 220426A and GRB 230812B the W increases with time, raising serious concerns regarding these theories. The results instead offer strong evidence that the GRB prompt phase involves the development of multiple emission zones, whose relative contributions change over time.

ABSTRACT. How supermassive black holes (SMBHs) grew to masses of up to $\sim 10^9\Msun$ within the first billion years of the Universe remains an outstanding question. Mergers of SMBHs have been considered an crucial channel in this rapid growth, but direct evidence is scarce. In recent years, several quasar pairs at $z \gtrsim 5$ have been discovered, with projected separations of only $\sim 100$ comoving kpc. These rare systems provide unique opportunities to study both structure formation and the mechanisms driving SMBH growth. To fully characterize them, however, we must determine their three-dimensional separations. Line-of-sight (l.o.s.) distances are typically estimated from emission-line redshifts, but their typical systematic uncertainties, $\Delta z \sim 0.02$, correspond to $\sim 30$ comoving Mpc at $z\gtrsim 5$. Such large uncertainties hinder our ability to constrain their clustering signal and, consequently, their cosmological environments. An alternative approach leverages the quasar proximity effect: the Ly$\alpha$ absorption spectrum should show an enhancement if a neighboring quasar lies in the foreground. In this talk, I present a method to infer relative l.o.s. positions by identifying peaks in the Ly$\alpha$ spectra. This technique achieves an accuracy of $\lesssim 0.5$ comoving Mpc, offering a significant improvement over traditional methods. This improvement provides new insights into quasar pair systems and the modeling of SMBH growth in cosmological simulations.

ABSTRACT. I will introduce some quasar surveys carried out in China in the last two decades, including the LAMOST quasar survey, the bright high-redshift quasar survey, and the survey for quasars behind the Galactic Plane. We have discovered more than 30,000 quasars at redshift z<4, more than 100 high-redshift quasars at z>5, and more than 1500 quasars behind Galactic Plane. These discoveries have contributed important quasar samples for studying the growth of supermassive black holes, changing-look active galactic nuclei, and the astrometric reference frame. I will also present the catalogs of almost 2 million quasar candidates selected with the multi-band optical and infrared sky surveys using machine-learning methods, which should be helpful to future quasar surveys in both northern and southern sky. Finally, I will present a plan for the quasar survey of Chinese Space Station Survey Telescope (CSST), which will likely produce 10 million quasar candidates and more than 1 million quasars identified with slitless spectra.

ABSTRACT. Deciphering how the cosmic web matures and how galaxies and supermassive black holes (SMBHs) evolve within its nodes and filaments requires well-characterized structures that expose the mechanisms driving hierarchical growth. The Cosmic Himalayas provides one such anchor. It is an extreme large-scale structure (LSS) at z~2.2, hosting 11 luminous Type-1 quasars with luminosities L_bol > 10^45.5 erg s^-1 within a comoving region about 40 cMpc on a side. This makes it the only structure with such a concentration across the 10,000 deg^2 SDSS sky, corresponding to a quasar overdensity about 30 times the cosmic average, a 17σ outlier under a Gaussian assumption. This concentration provides a unique laboratory to investigate how SMBH growth, galaxy assembly, and the intergalactic medium (IGM) interact during cosmic noon. Subaru/HSC NB387 observations reveal the spatial distribution of z=2.2 Lyman-alpha emitters (LAEs) and uncover a striking pattern: quasars align roughly perpendicular to a ~100 cMpc filament and do not coincide with LAE overdensities. Filament nodes exhibit distinct galaxy properties, while quasars occupy intermediate regions, suggesting a pivotal role in influencing their surroundings. The 3D IGM tomography using SDSS/eBOSS background quasars reveals a significant ionization gradient along the filament, with the 11 quasars located near the transition between ionized and neutral regions. This configuration indicates that clustered SMBHs can act as major drivers of ionizing feedback on scales of several tens of comoving-Mpc. Furthermore, SMGs are identified by JCMT/SCUBA-2, which are spatially offset from the LAEs, with quasars located in the intermediate regions between them. This configuration suggests an evolutionary sequence within the LSS, transitioning from dusty galaxies undergoing mergers to the quasar-phase galaxies and ultimately to massive galaxies with faded AGNs. A coordinated multi-wavelength campaign is now underway, including deep MeerKAT and ALMA observations and an approved Chandra Cycle 27 program targeting the quasar ensemble and filamentary nodes to quantify AGN energetics and hot-gas conditions. Taken together, the Cosmic Himalayas delivers a rare intermediate-redshift laboratory for stress-testing models of hierarchical structure formation and environment-driven galaxy and SMBH evolution, positioning it as a cornerstone for future investigations of AGN–galaxy–IGM interactions across the cosmic web.

ABSTRACT. “Changing-look” active galactic nuclei (CL-AGNs), as AGNs with temporary appearance or disappearance of their broad emission lines, show a spectral-type transition within a timescale of years to decades. The nature of this phenomenon remains an open issue. Building upon multi-epoch spectroscopy and multi-wavelength studies of CL-AGNs, this presentation will focus on: (1) the evolutionary role of CL-AGNs in the context of the coevolution of the supermassive black holes and the host galaxies where they reside in; and (2) a scenario of the origin of CL-AGNs stemming from their evolutionary role.

ABSTRACT. Dust-reddened quasars are thought to represent an important phase of supermassive black hole growth, yet their identification remains incomplete in wide-area surveys. We present a new color selection method to identify red quasar candidates in the COSMOS field by combining deep optical, near-infrared, and mid-infrared photometry. By extending K-band–based selection to significantly fainter magnitudes than previous surveys, we aim to probe a previously unexplored population of dust-obscured quasars. We explore multi-dimensional color diagnostics to separate red quasars from stars and galaxies and outline a strategy to evaluate the completeness and contamination of the selection. In this poster presentation, we describe the motivation, selection criteria, and future prospects of this approach.

ABSTRACT. During cosmic reionization, the clumpy intergalactic medium can impede the propagation of ionization fronts by boosting the recombination rates and opacity. These clumpy structures could also leave an imprint on a detectable 21cm signal. For example, minihalos are small dark matter halos that contain gas, but their densities are too low for atomic cooling.

To study them, we have developed a new radiation hydrodynamics method that is fast and accurate. We perform high-resolution cosmological (radiation) hydrodynamics simulations of these small-scale clumpy structures. We found that these clumpy structures can boost the cumulative number of recombinations per hydrogen atom by a factor of ten for late reionization. We are currently investigating the effects of density and dark matter models on these small-scale structures and their possible 21cm signatures.

ABSTRACT. Individual, luminous stars in background galaxies that are strongly lensed by foreground galaxy clusters are now regularly detected in deep, repeated JWST observations, thanks to the extra yet temporal boost of lensing magnification owing to stellar microlensing. Since these luminous stars must be among the youngest thus most massive stellar population in the relevant galaxies, their detection rate is extremely sensitive to the stellar initial mass function, as well as the most recent star formation rate.

In this talk, I will review our recent works in utilizing (i) the detection rate of lensed stars as a novel probe of stellar initial mass function beyond the local universe, which found its universality appears to hold at redshift ~1; and (ii) the relative detection rate of lensed stars that best traces blue and red supergiants to constrain the most recent star formation rate, which revealed that the star formation might have been more bursty than expected when one only use spectral energy distribution as constraints.

ABSTRACT. Protoclusters, galaxy clusters' high redshift progenitors, hold the keys to understanding the formation and evolution of clusters and their member galaxies. However, their cosmological distances and spatial extensions (tens of Mpc) have inhibited complete mapping of their structure and constituent galaxies, which is key to robustly linking protoclusters to their descendants. Here we report the discovery of the Bigfoot, a tridimensional structure at z = 3.98 including 11 subgroups traced by 55 (700) spectroscopic (photometric) redshifts with JWST, extending over 15*37*49cMpc^3 in the PRIMER-UDS field. Bigfoot's large-scale and mass function of member galaxies closely match constrained simulations' predictions for the progenitors of today's most massive clusters (M0 > 10^15 Msun). All subgroups with Mh > 10^12.5 Msun exhibit enhanced fractions of massive galaxies compared to lower-mass halos and field, demonstrating the accelerated formation of massive galaxies in massive halos. The presence of this massive protocluster with a large central halo (10^13.0Msun) in a JWST deep field bears important cosmological implication that favors high sigma_8 of PLANCK cosmology over low-redshift probes.

ABSTRACT. Chemical evolution is governed by the nucleosynthesis contribution from stars, which in turn is determined mostly by stellar mass. The stars that contribute the most include massive stars that explode as core-collapse supernovae, low- and intermediate-mass stars that evolve through the asymptotic giant branch (AGB), and supernovae of Type Ia. Probably the most uncertain aspect of chemical evolution models are theoretical stellar yields. In this talk I will focus on the contribution from AGB stars, which are important for producing carbon, nitrogen, and elements heavier than iron via the slow neutron capture process. Stars up to about 8 solar masses evolve through core hydrogen and helium burning, before ascending the AGB. It is during the AGB phase when mixing episodes can occur between the core and envelope, which enriches the envelope in freshly made elements. Strong outflows or winds remove that envelope into the interstellar medium, which eventually ends the AGB phase. In this talk I present the latest stellar yields from single and binary AGB stars calculated by our group. I will comment on the main uncertainties and our efforts to address them, including using stellar variability to determine the initial masses for the occurrence of the third dredge-up in real AGB stars.

ABSTRACT. This study compares the efficacy of the Lumme–Bowell and Hapke models in depicting the scattering behavior of light from materials that resemble asteroid surface characteristics. Reflectance studies were performed in our laboratory uti- lizing a variety of asteroid-analogue samples, including silicon carbide, boron carbide, brown corundum, olivine–basalt mixes, Martian JSC1 simulant, and Oman sand. The samples were selected that represented an extensive range of particle sizes (ranging from 13 µm to 600 µm) and porosity values (0.37 to 0.72) that closely resemble real asteroid regolith. The performance of each model was judged by how well it fits the experimental reflectance data, using the normalized chi-square error minimization method. In most cases, the Hapke model provided a better fit, yielding lower chi-square values and thus a closer agreement to the laboratory measurements. However, among the 30 different experiment cases, in three instances the Lumme-Bowell model gave a marginally better fit than Hapke model. The details will be discussed. In most of the 36 experimental configurations, the Hapke model yielded lower chi-square values, while in 6 cases the Lumme–Bowell model provided a slightly better fit. Across 450 individual cases, 101 followed the Hapke model, 34 followed the Lumme–Bowell model, 246 were consistent with both, and 69 did not match either model. The total experimental error was consistently below 2%, and model reflectances generally lie within the error bars. The details will be discussed. Both models can reproduce the observed reflectance behavior over a wide range of sample properties and geometries, so neither is universally superior. However, chi-square analysis indicates that the Hapke model generally offers a better overall fit for these asteroid-regolith analogues.

ABSTRACT. Star formation is a key driver of galactic evolution, and its efficiency is strongly regulated by environmental conditions such as radiation fields, metallicity, and gas density. The outer Milky Way exhibits markedly different physical environments compared to the inner Galaxy and the solar neighborhood, raising important questions about how these variations modify star-formation activity.

In this study, we analyze a large and statistically significant sample of star-forming regions in the outer Galaxy and compare their properties with those of nearby regions. Using multi-wavelength observations from a suite of national and international facilities, supplemented with archival data, we investigate how low metallicity and other environmental factors influence the major outcomes of the star-formation process.

We examine protoplanetary disk evolution and accretion, as well as the initial mass function (IMF), down to a mass limit of 0.1 M⊙—representing one of the most extensive and sensitive surveys of outer-Galaxy star-forming regions to date. Our analysis shows that disk fractions are significantly lower in low-metallicity environments, while mass-accretion rates remain broadly consistent with those in regions of solar metallicity. The characteristic mass of the IMF varies systematically with metallicity, in agreement with theoretical predictions. Additionally, the distribution of gas mass shows notable differences under low-metallicity conditions.

These results highlight the critical role of environmental variation in shaping star-formation pathways across the Milky Way.

ABSTRACT. Although supernovae are well-known endpoints of accreting white dwarfs, alternative theoretical possibilities have been widely discussed, such as the accretion-induced collapse (AIC) event as the endpoint of oxygen-neon (ONe) white dwarfs, either accret- ing up to or merging to exceed the Chandrasekhar limit (the maximum mass of a stable white dwarf). AIC is an important channel to form neutron stars, especially for those unusual systems that are unlikely produced by core-collapse supernovae. However, the observational evidence for this theoretically predicted event and its progenitor is very limited. In all of the known progenitor systems, white dwarfs increase in mass through accretion. Here, we report the discovery of an intriguing binary system Lan 11, composed of a stripped core-helium-burning hot subdwarf and an unseen compact object with a mass of 1.08M⊙ to 1.35M⊙. Our binary population synthesis calculations suggest that the latter is most likely to be an ONe white dwarf. Furthermore, the non- detection in deep radio observations by the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) does not exclude this interpretation. The total mass of this binary ranges from 1.67M⊙ to 1.92M⊙, significantly exceeding the Chandrasekhar limit. The reproduction of its evolutionary history indicates that the unique system has undergone two phases of common envelope ejection, implying a born nature of this massive ONe white dwarf rather than an accretion growth from its companion. These results, together with short orbital period of this binary (3.65 h), suggest that this system will merge in 500-540 Myr, largely triggering an AIC event, although the possibility of type Ia supernova cannot be entirely ruled out. This finding greatly provides valuable constraints on our understanding of stellar endpoints, whatever leading to an AIC or a supernova.

ABSTRACT. Stellar masses are often unknown or poorly constrained, which limits our ability to test models of stellar structure and evolution. To meaningfully compare theoretical predictions that use different input physics and chemical compositions, we require mass measurements with relative uncertainties below 1%. Such precision can only be reliably achieved in binary systems, where spectroscopy and astrometry can be combined to derive dynamical masses. For standard stars, my recent work has demonstrated that mass and distance can be determined with accuracies as high as 0.03%. In the case of binary Cepheids, which are particularly valuable as primary distance indicators, I have obtained some of the most precise distances currently available. These results enable direct tests of Gaia parallaxes and of the period–luminosity relations that underpin the extragalactic distance scale. In this contribution, I present the latest results obtained by combining high-resolution spectroscopy and long-baseline interferometry for both standard stars and binary Cepheids. I also outline the next steps in this program, focusing on the powerful synergy expected with Gaia epoch astrometry in the upcoming data release planned for 2026.

ABSTRACT. We revisit the long-standing question in stellar astrophysics: Why do post–main-sequence stars evolve into red giants (RGs) or red supergiants (RSGs)? We first compare stellar evolution models that reach the RG/RSG phase with those that remain blue and show that envelope expansion follows a refined “mirror principle,” in which the envelope moves in the opposite direction to its inner boundary defined by the hydrogen-burning shell, rather than to simple energy absorption. Building on this result, we construct steady-state envelope models to identify the physically realizable configurations of stellar envelopes. These solutions reproduce the refined mirror principle, demonstrate that the RG/RSG phase represents a limiting configuration for envelope expansion consistent with the Hayashi limit, and reveal that the yellow supergiant regime is structurally unstable, providing a physical explanation for the Hertzsprung gap.

ABSTRACT. Intermediate-mass Herbig Ae/Be stars serve as crucial astrophysical laboratories for understanding the transition between low-mass T Tauri stars and massive OB stars. A comprehensive, multi-wavelength synthesis of large-scale statistical surveys and high-resolution spectroscopy has fundamentally transformed our understanding of their pre-main-sequence evolution. Leveraging vast datasets from Gaia, LAMOST, and Spitzer, alongside precise optical and near-infrared spectroscopy, a unified empirical framework for disk dynamics, chemical evolution, and environmental feedback is now emerging. Automated surveys have vastly expanded the known population of hot emission-line stars, enabling robust statistical constraints on disc physics. Detailed kinematic and spectral analyses of emission lines—ranging from the HI series and O I to mid-infrared neon fine-structure lines—trace the physical conditions of the inner disk, pinpointing electron densities, dominant excitation mechanisms like Lyman-beta fluorescence, and the onset of extreme-ultraviolet-driven ionized outflows. Concurrently, mid-infrared catalogs map the structural and chemical evolution of the outer disk, illuminating how stellar radiation dictates the excitation of complex organics like PAHs and C60 fullerenes across different disk geometries. Furthermore, exploring the kinematic environments of these stars, from cavity-carving feedback mechanisms in star-forming regions to the characterization of rare wide-binary companions, contextualizes their formation on a macro scale. Ultimately, synthesizing these diverse observational signatures advances the overarching goal of determining how accretion, energetic stellar feedback, and environmental interactions collectively dictate circumstellar disk dispersal and set the initial conditions for planetary system formation.

ABSTRACT. Recent discussions at UNCOPUOS, the Hong Kong Space Sustainability Conference, and related workshops have increasingly converged on a point TCTB has advanced since 2019: the central obstacle to large-scale remediation of Massive Derelicts is not technological feasibility, but the absence of a practical mechanism for trusted cooperation across jurisdictions, ownership regimes, and competing political systems. Earlier TCTB papers, workshops, and the proposal for a UNCOPUOS Working Group anticipated this gap by arguing for a neutral, consent-based operational framework capable of translating shared concern into coordinated action. This paper revisits that argument through a resilience lens informed by the ongoing AURORA project and related stress-testing of future space scenarios. Across multiple plausible futures, resilience depends on three stabilizing capabilities: reliable space domain awareness and attribution, effective traffic coordination, and the ability to repair, reconstitute, or adapt space infrastructure under stress. Massive Derelicts are a particularly important test case because they present an immediate, physics-driven, and widely shared threat to orbital sustainability while avoiding the attribution uncertainty that complicates other classes of space risk. Everyone knows these objects exist, who launched them, and the scale of harm they may cause if left in place.

Against that backdrop, the paper argues that remediation should be understood not merely as debris control, but as foundational infrastructure for the orbital economy. Like a public utility, an initial state-supported governance and planning framework can reduce systemic risk, improve insurability, and unlock adjacent commercial markets in on-orbit servicing, logistics, salvage, manufacturing, and other follow-on activities. In this context, TCTB’s planning model provides a practical basis for cooperation by allocating costs among participating actors according to future opportunity rather than past fault, shifting the focus from retrospective blame to prospective benefit and enabling earlier entry into coordinated planning. At the same time, TCTB operates as a structured form of Track II diplomacy, using neutral institutional arrangements and private-sector participation to facilitate cooperation among states and commercial actors where direct alignment may be constrained. This approach aligns naturally with emerging collaboration platforms in Hong Kong and related international initiatives—including industry-led efforts such as CONFERS and the growing ecosystem of remediation and on-orbit servicing firms—creating opportunities for practical coordination through workshops, technical exchanges, and potential memorandum-based partnerships.

The paper presents TCTB as the institutional bridge needed to support that transition: a neutral, adaptive governance mechanism operating within existing law, but capable of enabling the cooperative planning, contracting, and execution that current institutions do not themselves provide. By linking the Hong Kong workshop process, recent UNCOPUOS developments, emerging insurance concerns, and resilience-based analysis, the paper argues that TCTB remains the most viable practical pathway for cooperative remediation of Massive Derelicts—and an essential step toward a more resilient and economically sustainable space environment.

ABSTRACT. Over the past three years, there have been frequent global space collision risk events, which have raised unprecedented attention to space debris and collision warning.

As the pioneer in China's commercial aerospace data services sector, Creatunion devote to providing services including space object cataloging, orbital culculation, collision warning and transit forecast to global clients. To date, we have established 21 optical observation stations in China and other regions, and launched the first commercial SSA satellite of China in September 2025.

ABSTRACT. The rapid developments and advancements in space technologies among Asia-Pacific nations has introduced novelty in earlier bipolar outer space dominance. Outer space as a strategic frontier has evolved incorporating a new dimension to regional as well as global geopolitics. This research attempts to examine the interplay between national and multilateral interests, global policies and regional cooperation with respect to outer space activities. The study also delves into an analysis of regional cooperation forums and contrasting national aspirations. The evolving architecture of outer space governance is articulated in a comprehensive manner. The trajectories and implications of actions in outer space are examined. The study elucidates the significance of foreign policies, narratives and legal strategies for long-term sustainability in outer space. The nations emerging as strong leaders in outer space have a critical role ensuring the 'benefit of all mankind' through global policies, international cooperation and regional balance of power. The early stages of cooperation for peaceful utilization of outer space eliminates risks, speculations, security threats and instability.

ABSTRACT. The challenge of space debris in low Earth orbit requires space regulators, satellite operators, and insurance providers to collaborate on a framework that ensures the sustainable development of the LEO economy and prevents the tragedy of the common. This study introduces the Operator Impact Model (OIM) based on a data-driven correlation framework designed to quantify the influence of operational decisions on orbital risk and associated financial burdens. The OIM integrates system dynamics concepts, including Causal Loop Diagrams and Stock and Flow Diagrams, with high-fidelity statistical datasets, and employs a multi-dimensional risk index that incorporates operational, economic, and legal components to inform investment in risk-mitigating technology and regulatory compliance. Analysis demonstrates that large constellation operators find active collision avoidance to be economically optimal, yielding a substantial net benefit of approximately $78.8 million annually compared to the cost of inaction. In contrast, small operators achieve the lowest overall cost by adopting a combined strategy of selective maneuvering for high-risk events supported by insurance coverage, totaling about $1.01 million annually. Crucially, scenario planning on systemic traffic growth shows that the quadratic relationship between object count and conjunction frequency causes risk to escalate exponentially, confirming that early strategic investment in propulsion capability is paramount to strategic survival. The OIM provides stakeholders with the necessary quantitative tools to balance short-term operational costs against long-term risk management, helping to establish the standardized risk indices and regulatory policies required for a sustainable low Earth orbit environment.