Study Findings: A Binary Model of Long-Period Radio Transients and White Dwarf Pulsars

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Credit: Casey Reed, NASA

Nature Astronomy abstract of study findings:

Long-period radio transients (LPTs) represent a recently uncovered class of Galactic radio sources exhibiting minutes to hours periodicities and highly polarized pulses of seconds to minutes duration. Their phenomenology does not fit exactly in any other class, although it might resemble that of radio magnetars or white dwarf (WD) pulsars. Two LPTs with confirmed multi-wavelength counterparts have now been identified as WD – M dwarf binaries. Moreover, WD pulsars (also WD – M dwarf systems), such as AR Scorpii and J1912−44, are known to exhibit short-period pulsations in hour-timescale orbits. Here we investigate the longest-lived LPT known, GPM J1839−10. We use a 36-year timing baseline to infer an ~8.75-h orbital period from radio data alone, and we show that it can be modelled in the same geometric framework as has been proposed for WD pulsars. Radio emission is triggered when the magnetic axis of a rotating WD intersects the wind from its companion, which naturally predicts the peculiar pulse modulation. Applying this to the WD pulsar J1912−44 successfully reproduces the emission profile and geometry as well. Our results indicate analogous emission-site geometries in these related classes of binary system, a possibility we extend to the broader LPT and WD pulsar population.

Citation: Horváth, C., Rea, N., Hurley-Walker, N. et al. A binary model of long-period radio transients and white dwarf pulsars. Nat Astron (2026).

https://doi.org/10.1038/s41550-025-02760-y

Study-related stories:

The Conversation – “Puzzling Slow Radio Pulses are Coming from Space. A New Study Could Finally Explain Them”

The Institute of Space Studies of Catalonia – “A Binary Star System Explains Mysterious Radio Pulses Across the Milky Way”

Sci.News – “Sporadic Radio Pulses Traced to White Dwarf-Red-Dwarf Binary System”

Study Findings: Electrical Conductivities of (Mg,Fe)O at Extreme Pressures and Implications for Planetary Magma Oceans

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Image (Credit): Artist’s rendering of deep layers of molten rock inside a super-earth generating powerful magnetic fields. (University of Rochester Laboratory for Laser Energetics illustration / Michael Franchot)

Nature Astronomy abstract of study findings:

During planet formation, planets undergo many impacts that can generate magma oceans. When these crystallize, part of the magma densifies via iron enrichment and migrates to the core–mantle boundary, forming an iron-rich basal magma ocean (BMO). The BMO could generate a dynamo in early Earth and super-Earths if the electrical conductivity of the BMO, which is thought to be sensitive to its Fe content, is sufficiently high. To test this hypothesis, here we conduct laser-driven shock experiments on ferropericlase (Mgx,Fe1−x)O (0.95 ≤ x ≤ 1) as an Fe-rich BMO analogue, perform density functional theory molecular dynamics simulations on MgO and calculate the long-term evolution of super-Earths. We find that the d.c. conductivities of MgO and (Mg,Fe)O are indistinguishable between 467 GPa and 1,400 GPa, despite previous predictions. We predict that super-Earths larger than 3–6 Earth masses can produce BMO-driven dynamos that are almost one order of magnitude stronger than core-driven dynamos for several billion years.

Citation: Nakajima, M., Harter, S.K., Jasko, A.V. et al. Electrical conductivities of (Mg,Fe)O at extreme pressures and implications for planetary magma oceans. Nat Astron (2026).

https://doi.org/10.1038/s41550-025-02729-x

Study-related stories:

University of Rochester – “Hidden Magma Oceans Could Shield Rocky Exoplanets from Harmful Radiation”

Earth Sky – “Powerful Magnetic Fields on Super-Earths Could Boost Chances of Life”

Universe Today – “Deep Magma Oceans Could Help Make Super-Earths Habitable”

Study Findings: A Carbon-rich Atmosphere on a Windy Pulsar Planet

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Image (Credit): Artist’s rendering of of an exoplanet orbiting a rapidly spinning neutron star called a pulsar. (NASA, ESA, CSA, Ralf Crawford (STScI))

Abstract of pre-publication study findings:

A handful of enigmatic Jupiter-mass objects have been discovered orbiting pulsars. One such object, PSR\,J2322-2650b, uniquely resembles a hot Jupiter exoplanet due to its minimum density of 1.8 g/cm^3 and its ~1900 K equilibrium temperature. We use JWST to observe PSR J2322-2650b’s emission spectrum across an entire orbit. In stark contrast to every known exoplanet orbiting a main-sequence star, we find an atmosphere rich in molecular carbon (C3, C2) with strong westward winds. Our observations open up new exoplanetary chemical (ultra-high C/O and C/N ratios of >100 and >10,000, respectively) and dynamical regimes (ultra-fast rotation with external irradiation) to observational study. The extreme carbon enrichment poses a severe challenge to the current understanding of “black widow” companions, which were expected to consist of a wider range of elements due to their origins as stripped stellar cores.

Citation: Michael Zhang et al. A carbon-rich atmosphere on a windy pulsar planet. ApJL (2025).

https://doi.org/10.48550/arXiv.2509.04558

Study-related stories:

University of Chicago – “NASA’s Webb Telescope Finds Bizarre Atmosphere on a Lemon-shaped Exoplanet”

Scientific American – “This Planet Is the Shape of a Lemon. That May Be the Least Weird Thing about It”

Space Daily – “Webb Maps Carbon Rich Atmosphere on Distorted Pulsar Planet”

Study Findings: Satellite Megaconstellations will Threaten Space-based Astronomy

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Image (Credit): The Hubble Space Telescope. (NASA)

Nature abstract of the study findings:

Rapidly growing satellite constellations have raised strong concerns among the scientific community. Reflections from satellites can be visible to the unaided eye and extremely bright for professional telescopes. These trails already affect astronomical images across the complete electromagnetic spectrum, with a noticeable cost for operations and mitigation efforts. Contrary to popular perception, satellite trails affect not only ground-based observatories but also space observatories such as the Hubble Space Telescope. However, the current number of satellites is only a fraction (less than 3%) of those to be launched in the next decade. Here we show a forecast of the satellite trail contamination levels for a series of international low-Earth-orbit telescopes on the basis of the proposed telecommunication industry constellations. Our results show that if these constellations are completed, one-third of the images of the Hubble Space Telescope will be contaminated, while the SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer), ARRAKIHS (Analysis of Resolved Remnants of Accreted galaxies as a Key Instrument for Halo Surveys) and Xuntian space telescopes will have more than 96% of their exposures affected, with 5.6,  69 and 92 trails per exposure, respectively, with an average surface brightness of μ = 19 ± 2 mag arcsec−2. Our results demonstrate that light contamination is a growing threat for space telescope operations. We propose a series of actions to minimize the impact of satellite constellations, allowing researchers to predict, model and correct unwanted satellite light pollution from science observations.

Citation: Borlaff, A.S., Marcum, P.M. & Howell, S.B. Satellite megaconstellations will threaten space-based astronomy. Nature 648, 51–57 (2025).

https://doi.org/10.1038/s41586-025-09759-5

Study-related stories:

Scientific American – “Satellites Swarming Low-Earth Orbit Threaten Space Telescopes”

News Scientist – “Planned Satellite Launches Could Ruin Hubble Space Telescope Images”

Orbital Today – “Satellite Boom Set To Disrupt Space Telescopes As Researchers Warn Of ‘Growing Threat’”

Study Findings: Not All Sub-Neptune Exoplanets Have Magma Oceans

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Credit: Image by Enrique from Pixabay

The Astrophysical Journal Letters abstract of the study findings:

The evolution and structure of sub-Neptunes may be strongly influenced by interactions between the outer gaseous envelope of the planet and a surface magma ocean. However, given the wide variety of permissible interior structures of these planets, it is unclear whether conditions at the envelope–mantle boundary will always permit a molten silicate layer or whether some sub-Neptunes might instead host a solid silicate surface. In this work, we use internal structure modeling to perform an extensive exploration of surface conditions within the sub-Neptune population across a range of bulk and atmospheric parameters. We find that a significant portion of the population may lack present-day magma oceans. In particular, planets with a high atmospheric mean molecular weight and large envelope mass fraction are likely to instead have a solid silicate surface, since the pressure at the envelope–mantle boundary is high enough that the silicates will be in solid postperovskite phase. This result is particularly relevant given recent inferences of high-mean molecular weight atmospheres from JWST observations of several sub-Neptunes. We apply this approach to a number of sub-Neptunes with existing or upcoming JWST observations and find that in almost all cases, a range of solutions exist that do not possess a present-day magma ocean. Our analysis provides critical context for interpreting sub-Neptunes and their atmospheres.

Citation: Bodie Breza et al. Not all sub-Neptune exoplanets have magma oceans. ApJL 993 L46 (2025).

https://doi.org/10.3847/2041-8213/ae0c07

Study-related stories:

Universe Today – “It Looks Like All Mini-Neptunes Aren’t Magma Oceans After All”

University of Chicago – “New Study Revises Our Picture of the Most Common Planets in the Galaxy”

Space.com – “Is Our Dream of Finding Ocean-Covered Exoplanets Drying Up?”