Dyson Spheres Around White and Red Dwarfs: Calculating the Search ⚡ экспресс
Dyson spheres are examined as potential technosignatures of extraterrestrial civilizations. Based on radiative balance, the equilibrium temperatures and spectral characteristics of such structures around white dwarfs and M-dwarfs are calculated, and their positions are plotted on a Hertzsprung–Russell diagram. It is established that spheres around white dwarfs radiate as cool blackbodies peaking in the near- to mid-infrared, while those around M-dwarfs are more intense but at longer wavelengths. Temperature falls proportionally to R_D^{-1/2}, and bolometric luminosity and flux are determined solely by the star's radiation. The results indicate that low-luminosity stars are convenient targets for searching for such constructs, and they set constraints for future infrared surveys.
If you build a giant blanket around a star, you get a Dyson sphere. It absorbs all the radiation and glows in invisible heat rays. No such sphere has been seen yet, but astronomers know: to find it, look for this thermal glow.
Scientists have calculated how the blanket heats up around two types of stars: white dwarfs (cooled-down remnants of suns, whose nature was first described by Chandrasekhar) and red M-dwarfs (the most common, cool stars). The larger the blanket's radius, the cooler it is — this follows from the law discovered by Planck. An unexpected conclusion: near a dim white dwarf, the blanket will heat up more but glow faintly, while around a bright red dwarf, it will remain barely warm, yet shine with full power.
This can be detected with the James Webb Space Telescope: a Dyson sphere doesn't hide the star, it only shifts its light into infrared — invisible heat, discovered by Herschel. Methods of brightness measurement and spectral analysis will help spot these strange objects and, perhaps, find traces of extraterrestrial intelligence.
🎯 If you built a Dyson sphere around the Sun at the distance of Earth's orbit, its surface would have room temperature — about 300 K.
🎬 Giant spheres around stars have appeared many times in science fiction, for example, in the series 'Star Trek: The Next Generation' (episode 'Relics').