Some of the most promising locations to search for possible alien megastructures, known as Dyson spheres, may not be stars like the Sun, but rather the galaxy’s smallest and dimmest stars.

Physicist Freeman Dyson introduced the idea of a Dyson sphere in 1960, describing it as a shell or, more realistically, a swarm of orbiting collectors that could capture most of a star’s energy. This concept has interested scientists searching for signs of advanced technology, but the question of how such a structure would appear in astronomical observations remained unknown.

Now, a new study, available on the arXiv preprint server, suggests that one of the coldest objects in a stellar system could, in principle, be an artificial megastructure rather than a natural astronomical object.

Amirnezam Amiri, a physicist at the University of Arkansas, explored the question of Dyson spheres by modeling these hypothetical megastructures around two often-overlooked types of stars: red M-dwarfs and white dwarfs. Amiri credits discussions with Harvard astronomer and founder of the Galileo Project, Avi Loeb, with helping shape the study.

Small, Dim, and Built to Last

Red dwarfs make up about 70% of the stars in the Milky Way. These stars burn slowly and can remain stable for trillions of years, much longer than the universe has even existed so far. White dwarfs offer a different benefit. As the dense remnants of stars like the Sun, they shrink to about 1% of their original size. This means a Dyson swarm could orbit much closer, requiring less material and a smaller structure than one built around a star like the Sun.

Amiri’s study explores how astronomers could detect such structures. Both red dwarfs and white dwarfs are dim enough that the infrared heat emitted by a Dyson swarm would stand out more clearly against the star’s own light.

Reading the Wreckage on a Star Chart

Astronomers use the Hertzsprung-Russell diagram to classify stars by temperature and brightness, and this tool is central to Amiri’s analysis. A Dyson swarm would not destroy a star’s energy, but would capture its light and re-emit it as heat at much longer wavelengths. 

In the new model, a star with a Dyson swarm would appear on the H-R diagram at the same luminosity but shifted dramatically toward the cool end. For instance, a red dwarf at about 3,000 K could appear surrounded by a shell as cold as 50 K, a difference of about two orders of magnitude. No known stars naturally occupy this region of the H-R diagram.

Identifying Factors

Dust and distant galaxies can also produce strong infrared emissions, so astronomers cannot identify a Dyson swarm using temperature alone. Amiri’s model points to a more complex set of clues. A true Dyson swarm would not show the silicate dust features seen in normal dusty disks, so its spectrum would be unusually smooth for an object with strong infrared emission.

Additionally, if the swarm consists of many separate collectors rather than a solid shell, there would be gaps that cause irregular, non-stellar flickering as the pieces move. Each of these signs can have natural causes, but finding them together is rare and hard to explain without considering artificial structures.

Future Observations

Astronomers can carry out this search using existing telescopes. The James Webb Space Telescope’s infrared instruments are already designed to detect faint, cold signals like these. The Vera C. Rubin Observatory’s new sky survey and the Nancy Grace Roman Space Telescope, which is expected to launch later this year, will add to these efforts. Together, they will generate the kinds of observations needed to search for the signatures described in the study.

Possible candidates for these future observations have already been identified. In 2024, Project Hephaistos identified seven potential Dyson sphere candidates among about 5 million cataloged stars, all linked to red dwarfs. One was ruled out after it was shown that a background black hole caused the observed signal. Several candidate Dyson sphere systems still remain under investigation. Amiri does not claim that any of these are actual Dyson spheres, and the paper makes this clear. Instead, the study offers a better way to tell true anomalies apart from dusty disks before using valuable telescope time. If a Dyson swarm surrounds a star and reradiates its energy at temperatures unlike those of natural stars, upcoming infrared surveys may finally be able to detect one.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.

Using near-UV spectroscopic data from the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope, astronomers discovered four white dwarfs orbiting nearby red dwarf stars.

The post Astronomers Discover Four New White Dwarfs in Solar Neighborhood appeared first on Sci.News: Breaking Science News.

James Webb Space Telescope (JWST) observations have revealed that the fate of planets after the death of their host star may be surprisingly warm, according to new research from the University of St Andrews.

The JWST observations offer a possible glimpse into what our solar system will be like billions of years from now, particularly for gas giants like Jupiter. In a recent paper published in Nature, the St Andrew researchers describe JWST observations of WD 1856 b, a Jupiter-sized exoplanet much warmer than would be expected for orbiting a dead white dwarf star.

Webb Observes WD 1856 b

A collaboration between NASA, the European Space Agency, and the Canadian Space Agency, the JWST has provided an unprecedented view of the distant edges of the universe, revealing many unexpected finds. Among these surprises was WD 1856 b, whose mass, temperature, and atmosphere readings reveal a surprisingly intact planet after the death of its star.

Our own Sun is projected to exhaust its supply of hydrogen in roughly five billion years, after which it will expand into a red giant star about 100 times larger than it is today, before shedding mass in its final transformation into a white dwarf star.

In the distant future, the Sun’s transformations will likely someday obliterate Mercury, Venus, and even Earth, yet scientists have remained uncertain about how more distant planets will fare. Only by observing real-world examples of planets orbiting dead stars can scientists gather more data on how these scenarios play out for the remaining planets, as with JWST’s observations of WD 1856 b.

A Strange System

Discovered in 2020 by the TESS survey and the Spitzer space telescope, WD 1856 b orbits the white dwarf star WD 1856+534 at a distance of around 80 light-years from Earth.

“The planet is quite the oddball. It’s about the size of Jupiter, but the white dwarf it orbits is the size of Earth, so the planet is seven times larger than its star,” said lead author Dr. Ryan MacDonald from the University of St Andrews.

Perhaps the most confounding element of this system is how close the exoplanet is to its host star. At a distance of 50 times closer than the Earth is to the Sun, the planet is at a distance at which the star’s red giant phase should have destroyed it. How the planet managed to escape the destruction while ultimately ending up so close to its star intrigued the St. Andrews team.

James Webb Space Telescope Data

As WD 1856 b performed a grazing transit, where just its top edge passed in front of the host star, JWST observations allowed the researchers to crucially measure mass and temperature data, allowing them to estimate its mass at between four and eleven times that of Jupiter.

“We’re used to looking back in time when we use telescopes, but this is the first time we have been able to look forward to what might happen to the outer planets around the remnant of a Sun-like star,” MacDonald said, adding that “it’s like using a time machine to peer into the distant future of our Solar System.”

Infrared light emitted by the planet’s own heat showed a surprising temperature of 126°C, which is 240°C hotter than it would be from the white dwarf’s heat alone.

JWST Tells The Future

As the team worked on the problem, the temperature mystery proved to be the answer to the distance issue.

“The big question is how WD 1856 b ended up where it is today, and there are two theories. One is that the planet was swallowed by the host star as it was dying, and managed to survive on the inside,” said Dr. Christopher O’Connor of Northwestern University. “The other is that the migration took place due to the gravitational effect of other objects in the system. The white dwarf is part of a triple star system, and the outer companion stars could have influenced WD 1856 b’s orbit.”

Since no present source of energy should be capable of generating this much heat on the exoplanet, the researchers suggest that it represents heat left over from being engulfed by the red giant or possibly through an inward migration. Cooling models the team analyzed indicated that the planet likely first captured heat about 3 to 3.5 billion years ago, then cooled to its present temperature and migrated closer to its host star.

“This is just the beginning of our exploration of planets orbiting dead stars with Webb, and the search for further planets orbiting white dwarfs is ongoing,” Dr. MacDonald concluded. “Our results show that stellar death is not the end – some planets experience a vibrant and lively future after the death of their star.”

The paper, “Aerosol and Hydrocarbons in the Atmosphere of a White Dwarf Planet,” appeared in Nature on July 1, 2026.

Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.

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