The Galaxy’s Coldest “Stars” May Actually Be Alien Megastructures
Summary
A study by amirnezam-amiri (University of Arkansas), preprinted on arXiv and slated for Universe, models how a Dyson swarm would appear to modern telescopes and which stars are the best hosts. Red dwarfs and white dwarfs are identified as prime candidates because their small size sharply reduces the construction material needed for a swarm — red-dwarf swarms at ~0.05–0.3 AU, white-dwarf swarms just millions of km above the surface. A swarm would absorb starlight and re-radiate it as infrared heat, shifting the host’s apparent position on the Hertzsprung-Russell diagram toward unnaturally cold effective temperatures (as low as ~50K around a normally ~3000K red dwarf) while leaving bolometric luminosity unchanged — a region no natural star occupies. The study also flags an unusually “clean,” dust-free spectrum and anomalous, non-natural brightness variations as distinguishing markers. JWST and WISE are named as the key instruments for the search, building on Project Hephaistos’s May 2024 identification of seven red-dwarf Dyson-sphere candidates (one later ruled out; five remain unconfirmed).
Key Claims
- A solid Dyson sphere is almost certainly physically unbuildable; a Dyson swarm of independent orbiting collectors is the realistic architecture.
- Red dwarfs and white dwarfs are the most material-efficient — and thus most plausible — Dyson swarm hosts due to their small radii.
- A red-dwarf swarm would orbit at roughly 0.05–0.3 AU; a white-dwarf swarm could sit just millions of km above the stellar surface.
- A Dyson swarm reprocesses starlight into infrared heat, driving the host’s effective temperature down to as low as ~50K (vs. ~3000K for a bare red dwarf) while conserving total luminosity — placing it in an unoccupied region of the H-R diagram.
- Absence of silicate dust emission (“clean” spectrum) and irregular, non-natural light-curve variability are proposed as additional discriminators from natural dusty/variable stars.
- JWST (and older WISE data) are best suited to this search due to their infrared sensitivity.
- Project Hephaistos (May 2024) found seven Dyson-sphere candidates, all red dwarfs, from ~5 million surveyed stars; one was ruled out via a coincidentally aligned background supermassive black hole, leaving five still under investigation.
Notable Quotes
“No known natural stars occupy that region of the H-R diagram. Any object found there would immediately become an intriguing candidate for further investigation.” — Universe Today/ScienceDaily summary of the Amiri study