Twin Star Cities in Perseus: A Guide to the Gaia-Based Study of h & χ Persei
This study uses Gaia DR3 data to investigate the famous double cluster h and χ Persei, identifying hundreds of member stars and confirming both clusters share similar ages, distances, metallicities, and motions. Through structural modeling, MCMC isochrone fitting, and SED analysis, the authors show the clusters likely formed together and continue to move through the Galaxy on nearly identical orbits. Their results strongly support a common origin and future interaction.
Can Rubin Spot an Incoming Asteroid in Time? Testing LSST’s Early-Warning Power
This paper evaluates how effectively the Vera C. Rubin Observatory’s LSST can detect asteroids on a direct collision course with Earth and how much warning time those detections provide. LSST performs well for large, hazardous asteroids but struggles to give long advance warning for smaller impactors, which are often discovered only days to weeks before impact. The authors show that cadence and linking limitations, not sky coverage, are the main bottlenecks, and argue that LSST must be paired with high-cadence surveys to achieve robust planetary defense.
When “Failed Stars” Get a Second Chance: The Strange Lives of Pink, Beige, and Maroon Dwarfs
Brown dwarfs that gain mass can evolve into three distinct objects: beige dwarfs that remain underluminous, maroon dwarfs that behave like ordinary low-mass stars, or pink dwarfs that temporarily experience frozen cores and long luminosity plateaus before reaching the main sequence. Their fate depends on how degenerate the core is when mass transfer occurs. Identifying these rare objects could reveal new details about binary evolution and stellar structure.
Mass Clues in Carbon and Nitrogen: How Red Giants Reveal Their Hidden Histories
Roberts et al. (2026) use asteroseismic masses and [C/N] birth-mass indicators to measure how much mass red giants lose and to identify stars that have likely undergone mass transfer. They find that RGB mass loss decreases with both mass and metallicity, contradicting classical Reimers’ predictions, and propose an adjusted η calibration. They also identify 207 unusual stars whose current masses cannot be explained without past binary interaction.
Metal Pipe: Building a Unified Path to Stellar Chemistry
Metal Pipe is a new stellar abundance pipeline designed to measure chemical compositions consistently across many star types, including cooler K and M dwarfs. By combining photometry, high-resolution spectra, and iterative modeling, it achieves agreement with major catalogs while overcoming limitations of earlier methods. Its design promises a unified, expandable framework for studying how stellar chemistry relates to planet formation.
Listening to the Milky Way’s Oldest Stars: What RR Lyrae Reveal About the Galactic Halo
This study uses a vast sample of RR Lyrae stars to map the chemistry and motions of the Milky Way’s stellar halo. The authors find strong evidence for a dual halo, with a more metal-rich inner component and a metal-poor outer component. By identifying dynamically tagged groups, they show that many halo stars share common origins from ancient mergers, preserving a record of the Galaxy’s assembly history.
Tracing Thamnos: Chemical Clues to a Very Metal-Poor Galactic Immigrant
Xie et al. investigate two retrograde stellar groups, Rg8 and Rg9, using high-resolution spectroscopy and find them chemically identical across all measured elements. Their shared very metal-poor population and lack of an α-knee indicate origin in a low-mass dwarf galaxy. The groups strongly overlap with the known Thamnos substructure, suggesting all three trace the same ancient accretion event in the Milky Way’s halo.
Carbon-Rich Fossils in a Neighboring Galaxy: Finding the First CEMP Stars in the Large Magellanic Cloud
This paper reports the first discovery of five carbon-enhanced metal-poor (CEMP) stars in the Large Magellanic Cloud, confirming that these ancient, carbon-rich stars exist beyond the Milky Way. Using SDSS-V spectra, the authors show that the stars are extremely metal-poor and strongly enriched in carbon. The result opens the door to testing how galactic environment influences early chemical evolution.
How Disc Conditions Shape Giant Planet Atmospheres
The paper investigates how different protoplanetary disc conditions affect the atmospheric composition of giant planets. Using simulations that track pebble drift, evaporation, and planetary migration, the authors find that most disc parameters have little influence on final atmospheric abundances. Instead, a planet’s composition is shaped mainly by where it forms and which evaporation fronts it crosses. This means atmospheric ratios like C/O, C/H, and O/H primarily trace formation location rather than disc details.
A Climate That Came and Went: Limit Cycles and the Changing Weather of Ancient Mars
The paper proposes that early Mars may have undergone episodic limit cycles, long cold periods interrupted by short warm intervals triggered by volcanic CO₂ buildup and enhanced greenhouse gases. Using a simplified climate model, Haqq-Misra shows that these warming spikes align with the timing of valley networks and delta formation. The study suggests Mars’ wet features may reflect transient, not sustained, warm climates driven by cyclic atmospheric processes.
Cosmic Wallflowers: How Lonely Star Clusters Bloomed in the Early Universe
This paper shows that extremely dense star clusters can form in the circumgalactic medium of young galaxies at very high redshift, rather than only inside galactic discs. Using high-resolution simulations, the authors find that these clusters arise from gravitational fragmentation of gas filaments, reach densities similar to JWST-observed systems, and may evolve into present-day globular clusters or sites of early black hole formation.
From Star Dust to Planets (and Back Again): Tracing Worlds Across a Lifetime
This white paper by Akke Corporaal examines how dust shapes planet formation and survival from a star’s birth to its late evolutionary stages. It highlights current limits in observing key dust-related processes and argues that next-generation infrared interferometry will be essential for resolving the tiny regions where planets form, migrate, and endure. The authors ultimately call for future facilities capable of mapping dusty environments at unprecedented resolution.
Could Mars Have Melted Ice Recently?
The study investigates whether liquid water could have formed Mars’ young gullies in the past 4 million years. Using advanced climate models, the authors find that surface frost cannot melt because sublimation cools it too strongly, and subsurface ice stays too deep and cold for melting. Even when ice is suddenly exposed, melting requires unrealistic conditions and produces too little water. The results suggest that most gullies likely formed through dry CO₂-driven processes rather than flowing water.
Spinning Slower: How the DART Impact Changed Asteroid Didymos
Researchers analyzed twenty years of light-curve data to determine that asteroid Didymos slowed its rotation by 0.18 seconds after the DART impact. This change, confirmed through detailed modeling and bootstrap tests, is best explained by slight reshaping of the asteroid, likely small landslides triggered by falling ejecta. The result provides new insight into how kinetic-impact missions can alter not just orbits but also asteroid spin states.
Metallicity in Motion: How a Cepheid’s Phase Reveals New Clues About the Leavitt Law
Bhuyan et al. investigate how metallicity affects the Leavitt Law by measuring period–luminosity relations at multiple pulsation phases for Cepheids in the Milky Way, LMC, and SMC. They find that both the PL slope and the metallicity term vary significantly with phase, especially between short- and long-period Cepheids. Although these variations average out to familiar mean-light results, the phase-dependent approach reveals where metallicity influences Cepheid brightness most strongly, offering a clearer path to improving cosmic distance measurements.
Measuring Turbulence: Key Quantities Behind the Driving Parameter
This paper studies how turbulence in a simulated Milky Way–like galaxy evolves and influences star formation. By tracking the turbulence driving parameter b, the authors find that compressive turbulence (high b) tends to occur about 10 Myr before increases in star formation, while supernova feedback later boosts turbulence and reduces b. Overall, turbulence cycles between compressive and mixed modes, tightly linked to the timing of star formation events.
Betelgeuse’s Hidden Partner: Tracing a Stellar Wake Inside a Supergiant Atmosphere
This paper argues that Betelgeuse’s long secondary period is caused by a companion star orbiting within its extended atmosphere. Optical and ultraviolet spectra show repeating changes in absorption and outflow that match the companion’s six-year orbit. These signatures are best explained by a dense, expanding wake of gas trailing behind the companion as it moves through the star’s chromosphere.
Mapping the Milky Way’s Hidden Superclouds
Kormann et al. use new Gaia-based 3D dust maps to identify seven massive, kiloparsec-long superclouds in the local Milky Way. These structures are highly elongated, mostly parallel, and contain most nearby star-forming regions. Many show vertical undulations, and despite differing masses, they maintain similar densities, suggesting pressure-regulated formation driven by large-scale Galactic dynamics rather than spiral arms.
A Cosmic Smoking Gun: Velocities Reveal a Violent Birth for a Trail of Dark Matter Free Galaxies
This paper reports precise velocity measurements for faint galaxies aligned in a narrow trail near NGC 1052. Five of seven galaxies follow a predicted velocity pattern, strongly supporting the idea that the trail formed in a single high speed collision between dwarf galaxies. The results provide compelling evidence that these galaxies are kinematically connected and formed together without dark matter.
Hidden Clusters in the Dust: Using RR Lyrae Stars to Uncover the Milky Way’s Missing Building Blocks
The paper presents a search for hidden globular clusters in the Milky Way’s dusty plane and bulge using RR Lyrae stars as tracers of old stellar populations. By combining Gaia and near-infrared data with a carefully calibrated clustering algorithm, the authors recover known clusters and identify several compact RR Lyrae groups that may represent previously undiscovered or disrupted clusters.