An infrared excess is a measurement of an astronomical source, typically a star, that in their spectral energy distribution has a greater measured infrared flux than expected by assuming the star is a blackbody radiator. Infrared excesses are often the result of circumstellar dust heated by starlight and reemitted at longer wavelengths. They are common in young stellar objects and evolved stars on the asymptotic giant branch or older.
In addition, monitoring for infrared excess emission from stellar systems is one possible method that could enable a search for large-scale stellar engineering projects of a hypothetical extraterrestrial civilization; for example a Dyson sphere or Dyson swarm. This infrared excess would be the outcome of the waste heat emitted by the aforementioned structures if they are considered blackbodies at temperatures close to 300 K.
Further reading
- Evans, Aneurin (1993). The Dusty Universe. Ellis Horwood. pp. 155–165.
References
Cotten, Tara H.; Song, Inseok (2016). "A Comprehensive Census of Nearby Infrared Excess Stars". The Astrophysical Journal Supplement Series. 225 (1): 15. arXiv:1606.01134. Bibcode:2016ApJS..225...15C. doi:10.3847/0067-0049/225/1/15. ISSN 0067-0049. S2CID 118438871. https://doi.org/10.3847%2F0067-0049%2F225%2F1%2F15 ↩
"Incredible Technology: How to Search for Advanced Alien Civilizations". Space.com. Archived from the original on 2015-09-29. Retrieved 2014-08-22. https://web.archive.org/web/20150929213551/http://m.space.com/24269-how-to-search-for-alien-civilizations.html ↩
Dyson, Freeman J. (1960-06-03). "Search for Artificial Stellar Sources of Infrared Radiation". Science. 131 (3414): 1667–1668. Bibcode:1960Sci...131.1667D. doi:10.1126/science.131.3414.1667. ISSN 0036-8075. PMID 17780673. S2CID 3195432. /wiki/Bibcode_(identifier) ↩
Wright, J. T.; Mullan, B.; Sigurdsson, S.; Povich, M. S. (2014). "The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. I. Background and Justification". The Astrophysical Journal. 792 (1): 26. arXiv:1408.1133. Bibcode:2014ApJ...792...26W. doi:10.1088/0004-637X/792/1/26. ISSN 0004-637X. https://doi.org/10.1088%2F0004-637X%2F792%2F1%2F26 ↩