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Out to what distance can we resolve the structure of a supernova remnant in the infrared? Until recently, it was only possible to do so for remnants in the Milky Way and the Magellanic Clouds, but JWST has now extended that capability to other nearby galaxies. In a recent research article, Sumit Sarbadhicary (The Ohio State University) and collaborators used JWST to study supernova remnants in the Triangulum Galaxy (Messier 33), a small spiral galaxy that is 2.7 million light-years away. The study area contained 40 supernova remnants that were previously identified at other wavelengths. The image above shows a portion of the galaxy’s southern spiral arm, where each white circle indicates a known supernova remnant. Infrared observations of supernova remnants are critical for understanding the physics of the interstellar medium and the composition, formation, and destruction of dust. To learn more about how JWST has pushed the limits of our search for extragalactic supernova remnants, and for details on each of the remnants detected by JWST in the Triangulum Galaxy, be sure to check out the full research article linked below.

Citation

“A First Look at Spatially Resolved Infrared Supernova Remnants in M33 with JWST,” Sumit K. Sarbadhicary et al 2025 ApJ 989 138. doi:10.3847/1538-4357/adec7a

Researchers estimate that there are at least 1,000 supernova remnants in our galaxy that should be visible at radio wavelengths today — but so far, only a few hundred have been confirmed. Embarking on a search for the missing supernova remnants, Brianna Ball (University of Alberta) and collaborators used radio observations from the Evolutionary Map of the Universe (EMU) and Polarization Sky Survey of the Universe’s Magnetism (POSSUM) surveys. The image above presents a portion of that search, overlaying the positions of various objects of interest atop a background of radio continuum emission from EMU. Several types of objects are indicated: previously known supernova remnants (red), previously identified candidate remnants (orange), new candidates (white), known H II regions (cyan), and young pulsars (green stars). So far, the team has newly confirmed 14 supernova remnants, six of which were identified for the first time thanks to EMU and POSSUM, and 37 new candidate remnants. As the EMU and POSSUM surveys continue, the authors expect that as many as 400 candidate supernova remnants may be spotted. If these candidates are confirmed, it would nearly close the gap between expected and observed numbers of supernova remnants in the regions covered by these surveys. To learn more about this search for supernova remnants, be sure to check out the full research article linked below.

Citation

“A Catalog of Galactic Supernova Remnants and Supernova Remnant Candidates from the EMU/POSSUM Radio Sky Surveys. I.,” B. D. Ball et al 2025 ApJ 988 75. doi:10.3847/1538-4357/addc63

closeup of a solar active region

solar active regions

Evolution of a cluster of active regions as seen in continuum emission (left column) and radial magnetic field (right column). Click to enlarge. [Dikpati et al. 2025]

Around Mother’s Day (12 May) last year, the Sun put on a spectacular display of solar activity. A clash between solar active regions incited 14 coronal mass ejections, launched multiple high-energy X-class solar flares, and sent shimmering aurorae as far south as Florida. The images above and to the right show the source of all this excitement: the active regions AR 13664 and AR 13668. In a recent research article, Mausumi Dikpati (High Altitude Observatory) and coauthors examined the origins of this cluster of active regions and why they were such a powerful source of solar storms. Their investigation showed that there are certain regions on the Sun where solar storms are more likely to arise. These regions occur where the Sun’s undulating bands of magnetic activity draw farthest apart, preventing oppositely directed magnetic fields from canceling one another out. In the case of the Mother’s Day superstorms, active regions 13664 and 13668 developed on the heels of a decaying active region, further contributing to their magnetic complexity. Ultimately, this analysis suggested that it may be possible to forecast damaging solar activity weeks in advance by predicting the locations of magnetically complex active regions and following their evolution. To learn more about the active regions that gave rise to the Mother’s Day superstorms, be sure to check out the full article linked below.

Citation

“Mother’s Day Superstorms: Pre- and Post-Storm Evolutionary Patterns of ARs 13664/8,” Mausumi Dikpati et al 2025 ApJ 988 108. doi:10.3847/1538-4357/addd09

IC 348

The glowing green nebula in this JWST image surrounds the star cluster IC 348, which is the subject of a recent study by Kevin Luhman (Penn State University) and Catarina Alves de Oliveira (European Space Agency). Using JWST’s Near-Infrared Camera, Luhman and Alves de Oliveira searched the cluster’s young stellar population for free-floating brown dwarfs — objects that are less massive than stars but more massive than most planets — and discovered multiple candidates with masses down to just twice the mass of Jupiter. Follow-up JWST spectroscopy confirmed the masses of these objects, making them the lowest-mass brown dwarfs known to date. In addition to their mass, these newly discovered brown dwarfs are remarkable because their spectra show evidence of hydrocarbon molecules, the exact identities of which are not yet known. Luhman and Alves de Oliveira proposed that low-mass brown dwarfs bearing this chemical signature be inducted into a new spectral class called “H” for “hydrocarbon.” To add to the intrigue of these objects, the authors also discovered signs of circumstellar disks around two of them, suggesting that they may be capable of forming and harboring planets. To learn more about the low-mass brown dwarfs in IC 348, be sure to check out the full research article linked below.

Citation

“A New Spectral Class of Brown Dwarfs at the Bottom of the IMF in IC 348,” K. L. Luhman and C. Alves de Oliveira 2025 ApJL 986 L14. doi:10.3847/2041-8213/addc55

combined Hubble and JWST image of GRB 221009A

The bright spot visible within its fuzzy host galaxy in the image above is the optical and infrared light from a superlative gamma-ray burst. Discovered in October 2022, GRB 221009A was the brightest gamma-ray burst ever observed by humans, and likely a once-in-ten-millennia event, earning it the nickname “the Brightest of All Time” or BOAT gamma-ray burst. This image shows the afterglow of this burst nearly a year after it exploded onto the scene. In a recent article, Huei Sears (Rutgers University) and collaborators analyzed Hubble and JWST observations made 185–345 days after the discovery of the burst. These observations captured the burst’s fading light and showed a distinct shift in the rate at which the light dimmed at around 50 days. This shift is evidence of powerful jets from the source of the burst. Sears’s team also discovered a blue component to the afterglow emission. This blue component may be due to the burst’s afterglow echoing off of dust in the host galaxy — if confirmed, this will mark the first time this feature has been detected. To learn more about what astronomers have discovered in the years since GRB 221009A was first spotted, be sure to check out the full research article linked below!

Citation

“Late-Time HST and JWST Observations of GRB 221009A: Evidence for a Break in the Light Curve at 50 Days,” Huei Sears et al 2025 ApJ 984 196. doi:10.3847/1538-4357/adc306

Today’s featured image is a beautiful representation of how simulated images of active black holes are made. In a recent research article, a team led by Aniket Sharma (Indian Institute of Science Education and Research Mohali) introduced Mahakala, a new ray-tracing algorithm that expertly tracks photons as they navigate the warped spacetimes surrounding black holes. Mahakala is named for the Egyptian deity who, as Sharma and collaborators describe, is “believed to be the depiction of absolute black, and the one who has the power to dissolve time and space into himself.” The image above shows a simulated accreting black hole at a wavelength of 1.3 millimeters, which is the same wavelength used by the Event Horizon Telescope to view the supermassive black holes at the center of the Milky Way and the galaxy Messier 87. The dotted lines streaming off to the right represent the paths that photons took on their way to the viewer as they curved around the black hole, which is visible among the forest of lines. In this representation, the color of each dot shows the synchrotron emission generated at that point in three-dimensional space. The team hopes that Mahakala, which can be run quickly and easily from a Python Jupyter notebook, helps make the complex world of general relativistic magnetohydrodynamics simulations more accessible. You can try it for yourself or learn more from the article linked below.

Citation

“Mahakala: A Python-Based Modular Ray-Tracing and Radiative Transfer Algorithm for Curved Spacetimes,” Aniket Sharma et al 2025 ApJ 985 40. doi:10.3847/1538-4357/adc104

Ring Nebula

The iconic and widely photographed Ring Nebula is one of the most recognizable planetary nebulae: short-lived, often brilliantly colored nebulae that form when low- to intermediate-mass stars shed their outer layers. The three images above show the central region of the Ring Nebula through the eyes of JWST’s Mid Infrared Instrument. The leftmost image clearly shows the Ring Nebula’s central star: a hot, crystallized stellar core called a white dwarf. In a recent research article, Raghvendra Sahai (Jet Propulsion Laboratory) and collaborators analyzed these JWST observations, leading to the discovery of a dusty disk around the Ring Nebula’s central star. This is just the second time that a resolved disk has been discovered around the central star of a planetary nebula. Disks with radii from 0.01 to 1,000 au have been found around evolved stars in the asymptotic giant branch phase through the planetary nebula phase, but it’s not yet clear how these disks form and how long they last. Most intriguingly, the presence of disks around highly evolved stars raises the possibility of a second phase of planet formation. To learn more about the JWST observations of the Ring Nebula, and what they tell us about the properties of the central star and its disk, be sure to check out the full research article linked below.

Citation

“JWST Observations of the Ring Nebula (NGC 6720). III. A Dusty Disk Around Its Central Star,” Raghvendra Sahai et al 2025 ApJ 985 101. doi:10.3847/1538-4357/adc91c

asteroid 2020 BX12 as seen by Arecibo

There are more than 37,000 asteroids known to come within 1.3 au of the Sun. Of this near-Earth asteroid population, roughly 2,500 are classified as potentially hazardous — being more than about 140 meters across and coming within 0.05 au of Earth’s orbit (about 20 times the distance between Earth and the Moon). In the image above, Luisa Fernanda Zambrano-Marin (University of Granada and University of Central Florida) and collaborators present observations of 2020 BX12, a potentially hazardous binary asteroid. The larger of the two asteroids in the system was discovered in January 2020 by the Asteroid Terrestrial-impact Last Alert System. About a week after the initial discovery, the 1,000-foot-wide Arecibo Telescope aimed its powerful planetary radar at 2020 BX12 and revealed the asteroid’s small companion. 2020 BX12 was the last of nearly 60 binary or triple near-Earth asteroids discovered with Arecibo before the telescope collapsed in December 2020. As Zambrano-Marin‘s team notes, the loss of Arecibo hampers scientists’ ability to find companions to near-Earth asteroids, which can be critical for determining the properties of these asteroids and guiding our planetary defense strategies. To learn more about this discovery, as well as what the team learned from follow-up spectroscopy, be sure to check out the full research article linked below.

Citation

“2020 BX12—The Last Binary Asteroid Discovered at Arecibo,” Luisa Fernanda Zambrano-Marin et al 2025 Planet. Sci. J. 6 91. doi:10.3847/PSJ/adbe39

Early investigations suggested that the galaxy cluster PSZ2G181.06+48.47, shown above, was an ordinary low-mass collection of galaxies. Later, radio observations revealed something remarkable: a pair of parenthesis-shaped radio sources located several million light-years from the center of the cluster. In a recent research article, Kamlesh Rajpurohit (Center for Astrophysics ∣ Harvard & Smithsonian) and collaborators used the Giant Metrewave Radio Telescope and the Karl J. Jansky Very Large Array to investigate PSZ2G181.06+48.47’s double radio sources, which are visible in red in the composite radio, optical, and X-ray image shown above. The team classified these features as radio relics, which are diffuse, extended, highly polarized radio sources that may be generated by shocks propagating through the intracluster medium. Radio relics are fairly rare, and PSZ2G181.06+48.47’s relics are unusual for several reasons: 1) there are two of them, and only about 30 double radio relics are known; 2) the galaxy cluster isn’t very massive, and relics are rare in low-mass clusters; and 3) the relics are separated from one another by about 11 million light-years, which is the largest separation known. To learn more about this pair of radio relics, including their likely cause, be sure to check out the full research article linked below.

Citation

“PSZ2 G181.06+48.47. II. Radio Analysis of a Low-Mass Cluster with Exceptionally Distant Radio Relics,” Kamlesh Rajpurohit et al 2025 ApJ 984 25. doi:10.3847/1538-4357/adbbb9

WR 8 and its ejecta nebula

This image shows glowing ejecta flung into space by a Wolf–Rayet star called WR 8. Wolf–Rayet stars are extremely hot and luminous massive stars that have cast away their outer layers. Because of their extreme winds, mass loss, and radiation, Wolf–Rayet stars are often surrounded by intricate nebulae. The nebula surrounding WR 8 was first reported in 2010, and now, Robert Fesen (Dartmouth College) and collaborators have revealed it in great detail. This image shows observations made in three broad visible-light bands as well as narrow bands that highlight emission from hydrogen and oxygen. The nebula’s clumpy ejecta and radial streaks stand out in blue. (The bright pinkish-orange streak that cuts across the image from the upper-left corner to the lower-right corner comes from an interstellar cloud in the background or foreground.) WR 8 is an interesting target because the star’s spectrum has features from two different Wolf–Rayet subclasses, suggesting that the star may be in the midst of a rapid (on the order of 10,000 years) transition from one class to another. A deeper investigation into this nebula may improve our understanding of this transition phase. To learn more about these new images of WR 8, be sure to check out the full article linked below.

Citation

“Deep Optical Images of the Ejecta Nebula around the Wolf–Rayet Star WR 8 (HD 62910),” Robert A. Fesen et al 2025 AJ 169 231. doi:10.3847/1538-3881/adbd41

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