Eta

Its story

Eta Sagittarii glows in the Archer’s bow as an M-type red giant about 146 light-years from Earth. Its light, filtered through a cool, distended atmosphere, shifts with quiet irregularity —the slow pulse of an aging star shedding its outer layers—. It belongs to a multiple system that telescopes resolve into separate components, rising over northern summer horizons buried within the densest band of the Milky Way, in that stretch of sky where the heavens become almost a river of stars.