It’s never been easier to get to know your neighbors: a new database introduces open star clusters, stellar associations, and substellar objects within 500 parsecs (1,630 light-years) of the Sun.

Too Much of a Good Thing

Astronomers today must contend with a difficult but delightful problem — there’s just so much data available. As a researcher attempting to study a particular slice of the universe, it can be challenging to pinpoint the correct data and to know whether you’ve collected all the data relevant to your science. This prospect is already daunting, and the deluge of data from surveys like the Vera C. Rubin Observatory’s Legacy Survey of Space and Time will make the situation even harder to manage.

This is where specialized databases can help. Often crafted with specific science goals in mind, database creators do the work for you by compiling objects within a well-defined parameter space. Today’s article describes a new database that takes a census of the solar neighborhood, with applications for studies of stellar evolution, exoplanets, and more.

Compiling Clusters

Jonathan Gagné (Montreal Planetarium; University of Montreal) and collaborators have compiled the Montreal Open Clusters and Associations (MOCA) database, which contains detailed information on nearby star clusters, stellar associations, and substellar objects.

Gagné’s team began the monumental task of constructing the database by amassing a list of nearby groups of stars from the literature, drawing on recent searches using data from the Gaia mission and other sources. This task required reconciling cluster names and memberships from multiple sources and detailing a cluster hierarchy that places subgroups within larger cluster structures.

In total, the complete database contains information about 10,259 star clusters and stellar associations and their individual members. The authors identified more than 11,000 new candidate cluster and association members, most of which are M dwarfs. The database also contains 1,620 substellar objects, 196 of which are newly identified through this work, and 101 candidate isolated planetary-mass objects.

Science with MOCA

For each star, the team compiled the available measurements from the literature and, from these core measurements, derived quantities like distance and spectral type. They then used empirical methods to estimate further properties like age, mass, and effective temperature.

Assigning ages to star clusters and stellar associations enhances the scientific value of the database, making it broadly accessible to studies of stellar and planetary evolution. For exoplanet science, the team identified 134 confirmed exoplanet systems and 121 planet candidates in young stellar associations with well-determined ages. This includes 46 confirmed and 53 candidate planets that appear to be assigned to an age-dated association for the first time.

MOCA already offers an impressive census of our patch of the Milky Way, but this isn’t its final iteration. As new data become available — including future Gaia data releases that will improve our understanding of cluster membership and reveal a population of astrometrically detected exoplanets — they will be incorporated into the existing database.

Interested in seeing what MOCA can do for your research? You can access the database online.

Citation

“The Montreal Open Clusters and Associations (MOCA) Database: A Census of Nearby Associations, Open Clusters, and Young Substellar Objects Within 500 pc of the Sun,” Jonathan Gagné et al 2026 ApJS 287 8. doi:10.3847/1538-4365/ae9b09

The post It’s a Beautiful Day in the (Solar) Neighborhood appeared first on AAS Nova.

Cheongho Han et al 2026 AJ 172 110

Four giant planets with masses of 0.2–2.5 Jupiter masses, orbiting hosts of 7–60% the mass of the Sun, have been discovered using microlensing; all the planets appear to lie beyond the snow lines of their hosts.

The post Four Cold Giant Planets Discovered by High-Cadence Microlensing Surveys appeared first on AAS Nova.

Qingzheng Yu et al 2026 ApJL 1007 L32

Using the Five-hundred-meter Aperture Spherical radio Telescope, astronomers have discovered an extended neutral hydrogen structure indicative of either tidal debris or accretion from the cosmic web.

The post Megaparsec-Scale Neutral Hydrogen Flows in the Neighborhood of Hickson Compact Group 100 appeared first on AAS Nova.

This image of the galactic center from the MeerKAT radio array shows wispy vertical lines known as galactic non-thermal filaments. These structures, which are tens of parsecs long and less than a tenth of a parsec wide, are found throughout a complex region called the central molecular zone. The filaments’ radio emission appears to come from charged particles spiraling around magnetic field lines, but it’s not yet known where the speeding particles that power this emission come from. Recently, Mohan Richter-Addo (University of Wisconsin–Madison) and collaborators used magnetohydrodynamics simulations to explore two potential sources: 1) the electron–positron winds of a pulsar or 2) a proton-rich mix of particles accelerated by interstellar shocks. The team found few discernible differences between simulated filaments illuminated by these two sources, but this work provided new avenues for future exploration. One facet that emerged from the team’s investigation is that filaments should grow longer as they age, with the maximum length set by the underlying magnetic field. This suggests that magnetohydrodynamic turbulence might play a role in shaping the filaments. To learn more about this exploration of galactic non-thermal filaments, be sure to check out the article linked below.

Citation

“The Effects of Cosmic-Ray Protons on Galactic Nonthermal Filaments,” Mohan Richter-Addo et al 2026 ApJ 1009 164. doi:10.3847/1538-4357/aea0c7

The post Featured Image: Examining Galactic Filaments appeared first on AAS Nova.

Rimpei Chiba et al 2026 ApJ 1006 132

Even in a noisy environment with fluctuations in pattern speed and encounters with the Sagittarius dwarf galaxy, a tree-ring structure arises in phase space measurements of the Milky Way’s galactic bar.

The post Tree-Ring Structure of Galactic Bar Resonance in N-Body Simulations appeared first on AAS Nova.

Researchers have followed up on the discovery of a rare binary system containing a white dwarf and a brown dwarf. This unusual pairing offers valuable insights into the physics of atmospheres subjected to strong radiation.

Odd Couple

In 2025, researchers searching through observations from the Transiting Exoplanet Survey Satellite (TESS) spotted an eclipsing binary system in which a brown dwarf orbits the white dwarf J0404+1112 every 2.93 hours. Only about a dozen white dwarf–brown dwarf binaries have been confirmed so far, and each newfound system offers clues to how substellar or planetary companions survive a star’s transition from main-sequence star to swollen red giant to blazing white dwarf.

Because the two objects orbit one another so closely, this remarkable system also offers researchers an opportunity to study the dynamics and chemistry of an atmosphere blasted with high-energy radiation, with important implications for close-in brown dwarfs and giant planets.

Insights from New Observations

Based on early data from TESS and SPECULOOS, Julien de Wit (Massachusetts Institute of Technology) and collaborators posited that the J0404+1112 system contained an unusually puffy low-mass white dwarf and a 25-Jupiter-mass brown dwarf. However, the initial data couldn’t fully constrain the white dwarf’s properties, leaving degeneracies between its temperature, radius, and other factors.

Now, the team has obtained new photometry from the Gran Telescopio Canarias and the United Kingdom Infra-Red Telescope, plus spectroscopy from the Gran Telescopio Canarias, to get a better sense of the system. These observations allowed them to break the degeneracies in the white dwarf’s properties, showing it to be an 0.60-solar-mass white dwarf that has been cooling for more than 10 million years to a present-day temperature of 28,000K. The brown dwarf also appears to be more massive than initially thought, weighing in at roughly 40 Jupiter masses.

Like Night and Day

Because the system’s orbit is almost exactly edge on from our point of view, the white dwarf is completely eclipsed as the much larger brown dwarf passes in front of it. This allows the contributions from the two components to be separated, and for the emission from the brown dwarf’s nightside to be measured. The authors constrained the brown dwarf’s nightside temperature to roughly 1750K. Its dayside temperatures are likely to be significantly higher — potentially around 3750K at the point where the white dwarf is directly overhead — but more data are needed to constrain the dayside temperature of this world.

The estimated day–night temperature difference for this brown dwarf places it in the realm of hot and ultra-hot Jupiters. However, it’s subjected to more ultraviolet radiation than a typical hot or ultra-hot Jupiter orbiting a main-sequence star. This makes J0404+1112 a valuable system for disentangling the interconnected effects of temperature, radiation environment, atmospheric composition, and other factors on hot or ultra-hot Jupiters and other strongly irradiated brown dwarfs. We can certainly expect to learn more about this rare system as new data are collected!

Citation

“J0404+1112: A 3 hr Eclipsing White Dwarf–Brown Dwarf Probing Multiple Atmospheric Regimes,” J. de Wit et al 2026 ApJL 1009 L40. doi:10.3847/2041-8213/ae9a97

The post Astronomers Get a Better Look at a Rare White Dwarf–Brown Dwarf Pair appeared first on AAS Nova.

Stefan J. Hofmeister et al 2026 ApJS 286 3

Researchers have assessed the diffusion and scattering within an ultraviolet instrument on board Solar Orbiter, which takes detailed observations of our home star from as close as about 60 au.

The post A Point-Spread Function for the Extreme Ultraviolet High-Resolution Imager on Board Solar Orbiter appeared first on AAS Nova.

Claire S. Ye and Raymond G. Carlberg 2026 ApJL 1007 L25

Pairing cold dark matter simulations with observations of stellar streams and globular clusters, researchers have extracted a declining power-law-like globular cluster initial mass function.

The post Inferring Globular Cluster Initial Mass Function from Stellar Streams appeared first on AAS Nova.

Hiromichi Tagawa et al 2026 ApJ 1006 121

Emission arising from the merger of stellar-mass black holes in an active galactic nucleus disk should be identifiable through monitoring of order 1,000 active galactic nuclei of sufficient luminosity for a year.

The post Electromagnetic Flares from Compact-Object Mergers in Active Galactic Nucleus Disks: Signatures and Predictions appeared first on AAS Nova.

P. Wang et al 2026 AJ 172 102

After identifying a new globular cluster, HSC 61, belonging to the Sagittarius dwarf galaxy, researchers have mapped the stellar stream, determined its metallicity, and analyzed the Sagittarius merger event.

The post The Properties of Globular Clusters and Elqui Associated with the Sagittarius Dwarf Galaxy appeared first on AAS Nova.

The Sun’s surface is peppered with spikes of plasma called spicules that appear to shift and twist over time. Recent simulations suggest a new explanation for the motion of solar spicules.

Jets in Motion

Solar spicules are tiny jets of solar plasma that last just a few minutes. When viewed along the solar limb, spicules resemble blades of grass blowing in the wind. Observations show these structures moving in a variety of ways: twisting, shifting side to side, splitting, and joining together. Though spicules were first identified more than a century ago, where these motions come from is still up for debate.

In a recent research article, Sahel Dey (University of Newcastle; Indian Institute of Astrophysics; Indian Institute of Science) and collaborators performed 3D magnetohydrodynamics simulations to investigate the source of solar spicules’ motion. The team’s simulations encompassed a volume of 6,000 × 9,000 × 37,000 kilometers that stretched from beneath the visible surface of the Sun up to the lower region of the Sun’s outer atmosphere, or corona. In this region, they applied a uniform vertical magnetic field, mimicking the conditions within a coronal hole, where the Sun’s magnetic field streams outward into the solar system

Convection low in the simulation region generates slow magnetohydrodynamic waves, which create pockets of hot, upward-moving plasma and launch the spicules. When looking at the 3D structure of the spicules, Dey and collaborators found that they are not individual jets as they appear to be in photographs of the Sun. Instead, the sea of spicules creates an interconnected structure similar to a folded curtain.

Simulating Spicules

The jet-like appearance arises when this arrangement is viewed from the side; the team created synthetic images of their simulated spicules that show individual jet-like features. These “jets” have properties similar to those of real spicules, lasting just 5–10 minutes, journeying upward at 20–70 kilometers per second, and reaching heights of 6,000–16,000 kilometers.

These simulations clearly demonstrate that what appear to be individual jets can arise from curtain-like plasma structures. Dey and collaborators showed that this network of spicules evolves over time, buoyed upward from below by a series of shocks, pulled down gradually by gravity, and buffeted by adjacent plasma.

The team showed that when spicules seem to rotate, merge, or split, these are largely apparent motions. For example, when two spicules appear to merge, this could be caused by different sections of a plasma curtain aligning along the line of sight. Some of the spicule rotation is due to what the authors term coronal swirling conduits: columns of rotating plasma interspersed within the network of spicules. These swirling plasma columns can transfer some of their motion to the spicules, especially when the spicules are falling back toward the solar surface.

This work demonstrates that a curtain-like configuration provides a viable explanation for the observed variety of spicule motions. Going forward, it will be critical to test this possibility further, as correctly interpreting the underlying structures of solar spicules is key to understanding how mass and energy are transferred to the solar corona.

Citation

“Solar Spicule Rotation Driven by Plasma Curtain–Vortex Interactions,” Sahel Dey et al 2026 ApJ 1008 132. doi:10.3847/1538-4357/ae8999

The post Drawing Back the Curtain on Solar Spicules appeared first on AAS Nova.

Mallory J. Kinczyk et al 2026 Planet. Sci. J. 7 182

The Gelato mission would collect a sample from the surface of the comet 67P/Churyumov–Gerasimenko, gathering material that, unlike coma materials collected in previous missions, is relatively unprocessed.

The post Gelato: A Mission Concept for Comet Surface Sample Return appeared first on AAS Nova.

Follow-up observations show that a recently discovered pulsar has two stellar companions, making it one of just a handful of millisecond pulsars known to be in triple-star systems.

An Unusual New Pulsar

Earlier this year, researchers reported the discovery of a pulsar with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The newfound pulsar, PSR J0435+3233, is a millisecond pulsar, rotating once every 3.2 milliseconds. What’s unique about this pulsar is how quickly it’s spinning down: its spin rate is decreasing roughly 100 times faster than other millisecond pulsars in our galaxy, suggesting an unusually strong magnetic field and the possibility of an exotic formation pathway.

The FAST observations also showed that the pulsar is not alone: it appears to be on an 8-day orbit with a white dwarf. Now, follow-up observations have revealed the pulsar’s membership in an intriguing stellar system.

From Radio to Gamma Rays

Zonglin Yang (National Astronomical Observatories, Chinese Academy of Sciences) and coauthors followed up on the discovery of PSR J0435+3233 using multiwavelength data from FAST, multiple optical and infrared observatories, and the Fermi Gamma-Ray Space Telescope.

With this broad dataset, the team confirmed the identity of the pulsar’s white-dwarf companion, detected gamma-ray emission from the pulsar, and identified a second previously unknown companion, a subgiant star roughly as massive as the Sun. These three stars are arranged in a hierarchical triple: the pulsar and white dwarf orbit one another tightly, and the subgiant is a more distant companion, orbiting in decades rather than days. Current observations show that the orbits of the inner binary and the outer star are tilted relative to one another, either nearly perpendicularly or at about 54 degrees. While a triple system of three closely intertwined stars invites chaos, this configuration is stable long term.

Insights into Stellar Evolution

While it’s common to find millisecond pulsars in binary systems — in fact, many millisecond pulsars are thought to spin up to their incredible speeds via accretion from a stellar companion — it’s rare to discover them in triple systems. Because this system is isolated out in the field rather than crowded together with other stars in a dense cluster, Yang and collaborators suspect that the three stars have been together since birth, as opposed to being assembled dynamically later on.

The most massive star in the trio would have hurried through its main-sequence lifetime in less than 10 million years, culminating in a supernova. The remaining two members of the system would have had to withstand this explosion, which the team found is possible but not especially likely; the likelihood of the system coming unglued due to a star going supernova depends on how much of a “kick” the explosion gives the newborn pulsar, and even in a zero-kick scenario, the likelihood of the system remaining bound is only 35%. The future evolution of the system will be less dramatic. The outer star will eventually evolve into a white dwarf, undergoing a gentle transition that poses no threat to the stability of the system.

Triple-star systems are common among massive stars, but how this configuration affects stellar evolution is still being explored. This discovery offers a valuable opportunity to study dynamics and stellar evolution in a rare triple system.

Citation

“The PSR J0435+3233 Triple System,” Z. L. Yang et al 2026 ApJL 1010 L9. doi:10.3847/2041-8213/aeaa29

The post A Pulsar in a Rare Triple System appeared first on AAS Nova.

M. Sten Delos et al 2026 ApJ 1006 125

The kinematics of small Milky Way satellites should differ depending on whether dark matter is warm or cold; current data constrain the mass of warm dark matter particles to >5.8 keV at 95% confidence.

The post Testing Warm Dark Matter with Kinematics of the Smallest Galaxies appeared first on AAS Nova.

Gokul P. Srinivasaragavan et al 2026 ApJL 1006 L36

Through modeling, researchers determined that a recently discovered supernova accompanied by an X-ray flash likely gave rise to a long-lived magnetar that may be surrounded by an accretion disk.

The post EP250827b/SN 2025wkm: An X-Ray Flash-Supernova Powered by a Central Engine and Circumstellar Interaction appeared first on AAS Nova.

In 3 million years or less, WASP-12b will tumble into its host star. It’s not surprising that the planet will meet its end this way, but it is surprising that it will happen so soon. New work tests a potential explanation for the planet’s rapid orbital decay.

Diagnosing a Doomed Planet

Roughly twice as wide as Jupiter and almost 50% more massive, exoplanet WASP-12b zips around its Sun-like stellar host every 1.09 days at a distance of just 0.023 au (3.4 million kilometers or 2.1 million miles). If placed in our solar system, WASP-12b would easily dethrone Mercury as the nearest planet to the Sun.

Observations show that WASP-12b’s already tiny orbit is shrinking, with each orbital period growing shorter at a rate of 29 milliseconds per year (Earth-year, that is). While we would expect the planet to slowly spiral inward due to tidal interactions with its star, it’s moving several orders of magnitude faster than predicted. The planet’s motion has so far defied all attempts to explain it, and now, a new research article by Caleb Lammers (Princeton University) and collaborators appears to topple yet another hypothesis for WASP-12b’s unexpectedly fast orbital decay.

A Tidy Tidal Explanation?

Previous work has proposed that WASP-12b’s rapidly shrinking orbit is due to obliquity tides, which could come into play if the planet had a nonzero obliquity, or axial tilt. Tidal dissipation generally works to keep close-in giant planets like WASP-12b from having a significant axial tilt. However, if you throw a second planet into the system, the companion can exert a torque that could force WASP-12b to remain tilted. This outside forcing, the hypothesis suggests, changes the orbital, spin, and tilt evolution of WASP-12b and ultimately pushes it toward its star far faster than expected without the tilt or the companion.

Lammers and coauthors examined this hypothesis by tracking how the angular momentum of a system containing both WASP-12b and a companion planet would evolve over time. As WASP-12b spirals inward, it loses angular momentum. For the planet’s lost angular momentum to be absorbed by the star and the companion planet — while maintaining a stable orbital configuration for both planets — the companion must orbit at least 0.06 au from the star and have a mass of at least 65 Earth masses.

The Mystery Persists

This companion mass and orbital distance are both larger than predicted by previous work, which had suggested that a 10–20-Earth-mass planet at 0.04 au would be sufficient to drive WASP-12b’s inward journey. Lammers and coauthors analyzed WASP-12’s radial velocity data for evidence of such a planet tugging on the star, but found none; only under extremely particular conditions could such a planet exist and not be detected in current data.

Taking their calculations further, the team found it unlikely that this mechanism is at work in planetary systems in general, not just in the WASP-12 system. This leaves the mystery of WASP-12b’s rapid orbital decay wide open, and with only 3 million years to ponder it before the planet’s demise.

Citation

“The Mysterious Inspiral of WASP-12 b: Why Obliquity Tides Cannot Drive Orbital Decay,” Caleb Lammers et al 2026 ApJL 1009 L43. doi:10.3847/2041-8213/aea405

The post Tilting WASP-12b Doesn’t Solve the Mystery of Its Inspiral appeared first on AAS Nova.

Arun Seshadri et al 2026 AJ 172 98

The molecular cloud complex G12.79+0.43 contains 82 young stellar object candidates; while this complex is spatially associated with a larger superbubble, it’s not yet clear if there is a causal association.

The post Star Formation at the Periphery of a Molecular Superbubble: The Case of G12.79+0.43 appeared first on AAS Nova.

Junyi Zhang et al 2026 ApJ 1004 66

Eruptions taking place in different locations on the Sun (e.g., on the solar limb versus on the disk) appear to have different spectral characteristics, paving a way for source regions of stellar flares to be studied.

The post Can We Distinguish the Source Region Location of Filament/Prominence Eruptions from the Sun-as-a-Star Hα Spectrum? appeared first on AAS Nova.

What at first might appear to be abstract pixel art or a fuzzy photograph of skyglow from a distant city is actually a representation of radio emission from the pulsar at the center of the Crab Nebula. When a pulsar’s radio emission passes through a region of ionized gas — like the complex filaments of the Crab Nebula — the plasma deflects the radio signal from its intended course. This detour can create “echoes”: copies of the pulsar signal that arrive later than the original pulse. Thierry Serafin Nadeau (University of Toronto) and collaborators studied these echoes from the Crab pulsar by compiling an archive of giant pulses detected over 2.5 years by the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Giant pulses, which are brighter and narrower than typical pulses, offer a powerful way to probe plasma echoes. The image above shows sweeping parabola-shaped echoes during two particularly active periods. The color shows the frequencies at which power was received: mainly at low (blue), high (red), or all (yellow-white) frequencies. This dataset revealed for the first time a feature predicted to exist but never seen: echoes from plasma structures that never pass directly in front of the pulsar from our point of view. To learn more about the echoes of the Crab pulsar, be sure to check out the research article linked below.

Citation

“Echoes in Different Tempo: Long-Term Monitoring of Crab Echoes with CHIME,” Thierry Serafin Nadeau et al 2026 ApJ 1006 82. doi:10.3847/1538-4357/ae7336

The post Featured Image: Echoes of Giant Pulses appeared first on AAS Nova.

S. Corley et al 2026 ApJS 285 60

The upcoming Wide Fast Deep and Deep Drilling Field surveys have limited potential to confirm exoplanets, with just a handful of hot planets around M-dwarf stars likely to be confirmed in the Deep Drilling Field.

The post Predictions of Transiting Exoplanet Confirmations from Rubin LSST Surveys appeared first on AAS Nova.