The “Little Red Dots 2026” online workshop brought together 33 invited speakers, 19 flash talks and in total 230 participants. The workshop was dedicated to the discussion of these newly discovered compact red objects in the early Universe and their physical nature.
Most massive stars form in binary systems, which profoundly influence their subsequent evolution. However, how such systems form remains poorly understood, with several competing scenarios proposed, including disk fragmentation, core fragmentation and capture. Determining the orbital architectures of massive binaries, particularly during their earliest embedded phases, is, therefore, crucial for distinguishing among these formation pathways, but direct measurements of their three-dimensional motions have remained exceptionally challenging. Here we present high-resolution, multi-epoch submillimetre-to-centimetre ALMA and JVLA observations of the massive protobinary IRAS 07299−1651, complemented by JWST and VLT infrared imaging. We detect the orbital proper motion of the binary components, enabling a full three-dimensional orbital reconstruction. Combining orbital fitting, multi-wavelength continuum modelling, hydrogen recombination line kinematics and jet observations, we find that the preferred orbital solutions are highly eccentric and close to parabolic, and both circumstellar disks are strongly misaligned with the orbital plane. These properties are naturally explained by a ‘core-merger’ scenario in which the two protostars originated independently from initially unbound cores that recently underwent a near-parabolic encounter, producing an eccentric binary with a current separation of about 200 au. These findings suggest that the core-merger process may represent an important pathway for forming eccentric massive binaries. Multi-epoch ALMA and VLA observations reveal the three-dimensional orbital motion of a massive protobinary. The orbits are highly eccentric and close to parabolic, with strong disk–orbit misalignment, suggesting a core-merger pathway for massive binary formation.
At IAU Symposium 405 in Brno, Czech Republic, the Galactic Centre emerged as a nearby laboratory for galactic nuclei, which links the central supermassive black hole, dense stellar populations and multiphase gas into a connected ecosystem across space and time.
The use of agentic large language models obviates human interpretation of scientific results, and will lead to substantial distrust in the literature.
Among icy moons of the outer Solar System, subsurface water oceans and large collisions both seem to be common, but the impact of the latter on the presence and persistence of the former is unclear and has rarely been investigated. Here we interface a smoothed-particle hydrodynamics model to simulate collisions with a thermal-structural evolution model to simulate the evolution of moons pre-collision, post-collision and without a collision. Overall, even such large-scale collisions affect only the ocean thickness or longevity, and the presence or absence of an ocean is affected for only a part of a moon’s history. In reaccreted moons, the ocean survives the impact and becomes much thicker inside larger moons with radius near 1,000 km, whereas an ocean that would otherwise arise inside moons with radius near 500 km is absent because the collision promotes ice–rock differentiation. Our simulations have not yielded an ocean developed post-impact—whether directly via collisional or reaccretional heating or indirectly through tidal heating due to collision-induced orbital changes—in a moon that would otherwise have remained frozen. The ocean-enhancing effect is pronounced only for late disruptive impacts onto large, 1,000-km-class targets, which are unlikely in recent Solar System history. Modelling shows that large collisions with the icy moons of the giant planets do not affect drastically the occurrence of subsurface oceans inside reassembled icy moons throughout their history. They solely affect ocean thickness or longevity.
Small planetary bodies record the processes that shaped the Solar System, but their surfaces and interiors often evolve in unexpected ways. Deimos, the potato-shaped, 12-km-diameter outer satellite of Mars, has a strikingly smooth surface covered by fine regolith, in contrast to its heavily cratered and grooved sibling, 22-km-diameter Phobos. Moreover, Deimos’s topography is dominated by a single large south-polar depression, whose formation we simulate to constrain the moon’s interior and surface geomechanical properties and to explain the origin and distribution of its regolith. Here we find that an oblique impact by a 320-m-diameter projectile can quantitatively account for this depression, the global regolith layer and surface features such as bright streaks and crater infill. Our results show that Deimos’s upper layers are extremely weak and that its interior is highly porous and dissipative, resembling the recently visited rubble-pile asteroids rather than lunar regolith. This suggests that small dark moons and asteroids, despite their specific histories, may converge on similar physical states. Simulations show that the large depression at the south pole of the Martian moon Deimos formed in an oblique impact that also smoothed its surface, revealing a very weak surface over a porous, fractured, rubble-pile-like interior.
Astro-tourism programmes have emerged across the world as a form of scientific engagement. The Carnarvon Astro Guides initiative in the Karoo, South Africa, is one of them, aiming to connect the large-scale astronomical infrastructure (including the SKA) to local socio-economic development.
The Universe between recombination (redshift z ≈ 1,000 or 400,000 years after the Big Bang) and the later formation of the first generation of stars at z ≈ 30 to 12 (~100 to 300 million years after the Big Bang) remains largely unexplored. During these epochs, the Universe was filled with diffuse neutral hydrogen. Studying this ‘dark age’ and ‘cosmic dawn’ before the reionization by early galaxies is crucial for understanding fundamental cosmological concepts, including dark matter and cosmic structure formation. Observations of the 21-cm line emitted by neutral hydrogen are key, but ground-based radio telescopes face challenges such as radiofrequency interference and atmospheric effects, which effectively prevent observations below ~45 MHz, thereby missing the dark ages. Here we propose the cost-effective CosmoCube lunar mission, which could overcome these limitations by conducting observations from the far side of the Moon’s orbit launching in only a few years, before the spectrum from the far side of the Moon is contaminated by human-made radio signals. The cost-effective CosmoCube mission is proposed to observe the 21-cm line emitted by neutral hydrogen from the relatively uncontaminated radio environment of the far side of the Moon.
The first all-African space exploration mission, Africa2Moon, is to be launched to the lunar south pole with Chang’e-8, scheduled for 2029.
Accretion and relativistic jet formation in black holes occur across a wide range of their masses, revealing qualitative and quantitative similarities that connect the entire population of black holes. In March 2026, researchers from all areas across the black hole mass spectrum met in Oxford to educate, explore and forge new research directions.
Trihydrogen cations ( $${{\rm{H}}}_{3}^{+}$$ ), a key diagnostic of atmospheric energy balance, are produced through ionization by solar radiation and particle impacts in hydrogen-rich planetary atmospheres. At Jupiter, $${{\rm{H}}}_{3}^{+}$$ is produced most efficiently in the auroral region through electron precipitation and has a leading role in magnetosphere–ionosphere coupling by regulating ionospheric conductance. Previously, the properties of $${{\rm{H}}}_{3}^{+}$$ have been determined from remote sensing, with plasma parameters retrieved from its infrared emissions, although these measurements are limited by line-of-sight integration and restricted altitude resolution. Here we report the unambiguous, direct in situ detection of $${{\rm{H}}}_{3}^{+}$$ plasma in the auroral region. Furthermore, intermittent $${{\rm{H}}}_{3}^{+}$$ outflows are measured high above the ionosphere, with upwards velocities exceeding Jupiter’s escape speed, confirming atmospheric escape of $${{\rm{H}}}_{3}^{+}$$ . We propose that $${{\rm{H}}}_{3}^{+}$$ outflow originates in the auroral upwards electric current region, initially triggered by plasma-wave interactions and subsequently accelerated by the electric potential structure above the ionosphere. This study reveals a $${{\rm{H}}}_{3}^{+}$$ -mediated pathway for mass and energy transfer between the ionosphere and magnetosphere of Jupiter, constituting an atmospheric escape with a loss rate of order 1026 s−1. Similar mechanisms may operate at other planets with infrared aurorae and strong magnetic fields. In Jupiter’s polar region, $${{\rm{H}}}_{3}^{+}$$ has a key role in atmospheric heating and ionospheric conductance. Juno measurements show in situ detection of $${{\rm{H}}}_{3}^{+}$$ and provide direct evidence of its escape, revealing a pathway for energy transfer between the magnetosphere and the ionosphere.
The majority of massive stars are born in close binary systems. As stars expand when they age, mass transfer or even a merger with their companion is inevitable. However, most binary interaction products appear as single stars, such that the main evidence of their exciting past is lost. Here, in a comprehensive grid of detailed massive binary evolution models, we find systematic trends in chemical surface abundances that allow the identification of the past mass gainers. We develop an analytic framework that is independent of specific evolutionary models, to constrain the amount and composition of the accreted material from their observed surface abundances. This yields tight constraints on the uncertain mass transfer physics in massive binary stars and allows us to reconstruct the past evolutionary history of the progenitor binary system. This method, which is shown to also constrain binary mergers (for example, SN 1987A), is applied to some of the best-studied OB stars so far. For γ Columbae, suggested to be an envelope-stripped star, we show that it is a mass gainer instead, whose companion star probably formed a stripped-envelope supernova. Our results highlight surface abundance measurements as a powerful tool to improve our understanding of massive binary systems evolving towards supernovae and compact object binaries. Some apparent single stars hide a dramatic history of past interaction with their companions. The authors show how chemical fingerprints left on a star’s surface can unmask these binary interaction products and unravel their past evolution.
Vertical corrugations—wave-like undulations in galactic disks—are potential imprints of past dynamical events that offer key constraints on galaxy evolution. While large-scale corrugations superimposed on the Galactic warp have recently been detected using young stellar tracers, the corresponding widespread structure within the molecular gas remains largely unexplored due to the challenge of disentangling subtle amplitudes from the dominant warp signal. By analysing over 30,000 molecular clouds from the Milky Way Imaging Scroll Painting survey, we systematically characterize widespread corrugations across the outer CO disk. After subtracting a global CO warp model, residual vertical displacements reveal coherent wave-like structures spanning much of the outer disk. Quantitative modelling yields characteristic vertical amplitudes of ~100–200 pc and radial wavelengths of ~3.9–7.9 kpc, and identifies a coherent azimuthal corrugation mode with a 52.6° (~11.6 kpc) wavelength at Galactocentric radius R ≈ 12.7 kpc, extending ~40 kpc. These findings provide direct evidence that vertical corrugations are a common large-scale feature of the outer Galactic molecular disk, offering insights into the three-dimensional structure and dynamics of spiral galaxies. Using more than 30,000 molecular clouds, this study reveals widespread wave-like corrugations superimposed on the warp of the Milky Way’s outer molecular disk, offering insight into its three-dimensional structure and dynamics.
