The coldest 'stars' in the galaxy might actually be alien megastructures‎

Ever since physicist Freeman Dyson first proposed the concept in 1960, the "Dyson sphere" has been the holy grail of techno-signature hunters. A highly advanced civilization could build a "sphere" (or, in our more modern understanding, a "swarm" of smaller components) around their host star to harvest its entire energy output. We know, in theory at least, that such a swarm could exist—but what would it actually look like if we were able to observe one? A new paper, available on the arXiv pre-print server and soon to be published in Universe from Amirnezam Amiri of the University of Arkansas, digs into that question—and in the process discloses the types of stars that are the most likely to find them around.