Young disk around WRAY 15-1880 may contain a primitive planetary system - Astronomy & Space Astronomy - Planetary Sciences

Left: Qϕ image of WRAY 15-1880 obtained from the SPHERE polarimetric data. The red dot at the center of the image marks the position of the star; the dashed white circle is the size of the coronagraph used in this observation. The dotted straight lines mark the major and minor axes, as obtained by Curone et al. (2025). Right: similar image, but projected on the disk plane (i = 39.22 deg) and rotated to have the major axis vertical and the minor axis horizontal. Credit: arXiv (2026). DOI: 10.48550/arxiv.2606.10816

Italian astronomers have used the Very Large Telescope (VLT) to perform polarimetric observations of the star WRAY 15-1880 and its young circumstellar disk. Results of the new observations, presented June 10 on the arXiv preprint server, suggest that this disk may host a primitive planetary system.

A young star with a disk

Circumstellar disks are accretion disks orbiting stars, composed of gas, dust, planetesimals, asteroids or collision fragments. Around the youngest stars, they are the reservoirs of material out of which planets may form.

At a distance of some 492 light-years from Earth, WRAY 15-1880 (also known as RX J1842.9-3532) is a solar-type classical T Tau star in the CrA-North subregion of the Corona Australis (CrA) complex. It has a mass of around 1.24 solar masses and is estimated to be 2.8 million years old.

Previous observations of WRAY 15-1880 have found that it is surrounded by a pre-transitional circumstellar disk with a gap, whose mass is estimated to be some 0.01 solar masses. The disk extends to a distance of 87 AU from the star and has an inclination of approximately 39.32 degrees.

All eyes on WRAY 15-1880

Due to the relative proximity and young age of WRAY 15-1880, a team of astronomers led by Elisabetta Rigliaco of the Astronomical Observatory of Padua in Italy turned its attention to this star and its disk, hoping to gather valuable data on how planetary systems are born. For this purpose, the team employed VLT's Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) and analyzed archival data from other VLT instruments and from the Atacama Large Millimeter/submillimeter Array (ALMA).

The observations conducted by Rigliaco's team revealed the presence of a companion object possibly orbiting WRAY 15-1880. The collected data suggest that this object is a Jupiter-like planet with a mass within the range of 1.7–7.6 Jupiter masses. The spectrum of this source indicates a T3 spectral type, corresponding to a temperature of about 1,200 K.

Planet or not?

However, the researchers are cautious about claiming that there is a planet in the disk of WRAY 15-1880. They explain that they cannot completely exclude the possibility that the object imaged in high-contrast imaging results from a combination of emission by a photosphere with starlight reflected or scattered by dust, or that it may be—for instance—an artifact due to irregularities in the disk structure.

The authors of the paper added that the candidate exoplanet of WRAY 15-1880 orbits the star on a very wide and circular orbit—with an orbital period of about 127 years and semimajor axis of approximately 25.7 AU.

The scientists concluded that if their discovery is confirmed, WRAY 15-1880 would be one of the most primitive forming planetary systems known to date. Moreover, WRAY 15-1880 would also be added to the short list of stars hosting a disk and planets imaged simultaneously. 

by Tomasz Nowakowski, Phys.org

edited by Stephanie Baum, reviewed by Robert Egan 

Source: Young disk around WRAY 15-1880 may contain a primitive planetary system 

Why Alzheimer’s Steals Sleep, And How Scientists Got It Back

Picture a small kitchen fire. A contained mess you could put out in seconds, except instead of a fire extinguisher, the sprinkler system kicks in and floods the entire house. That, according to a new study from the University of Kentucky, is essentially what happens inside the brains of people with Alzheimer’s disease.

For years, scientists assumed that sleep problems in Alzheimer’s came from damaged neurons or the physical clutter of amyloid plaques, the sticky protein clumps that build up in the brain. But a team led by Shannon Macauley and Nicholas Constantino has found the real culprit is something else entirely: the brain’s own immune cells, called microglia.

Microglia are supposed to be the cleanup crew, swarming in to deal with the plaques. But in doing so, they trigger a cascade of inflammation, “as if the microglia are partying all night,” as Macauley put it, that keeps the brain from settling into deep, restorative sleep.

To prove it, the researchers fitted mice with tiny EEG and EMG devices, the same kind of technology used to study human sleep, and tracked brain activity in animals genetically prone to developing amyloid plaques. Then they gave the mice a drug that temporarily wiped out about 87% of their microglia. The plaques stayed exactly where they were. But the mice got back more than two hours of sleep a night.

Even more surprising: sleep loss didn’t get progressively worse as plaques accumulated. Mice with early-stage plaque buildup lost about the same amount of sleep as mice with more than double the plaque burden months later, suggesting the very first wave of immune activity may be enough to break the sleep cycle, with little room for it to get worse from there.

Why does this matter beyond the lab? Because deep, non-REM sleep is when the brain does its housekeeping, clearing out metabolic waste, consolidating memories, repairing itself. Lose that stage and you may be feeding a vicious cycle: bad sleep worsens the brain’s ability to clean itself, which may in turn worsen the disease.

The team isn’t proposing we start wiping out microglia in humans, that’s neither safe nor practical. Instead, they’re now testing whether existing, already-approved drugs (including a diabetes medication and an anti-seizure drug) can calm overactive microglia without eliminating them, in hopes of interrupting this cycle years before memory loss ever begins.

Source: University of Kentucky, published in Alzheimer’s & Dementia (2026)

Original paper: Early microglial response to amyloid plaques drives sleep loss in Alzheimer’s disease, Alzheimer’s & Dementia (2026) 

Source: Why Alzheimer’s Steals Sleep, And How Scientists Got It Back