Delta Leonis, on the Lion's Back

Zosma is Delta Leonis, a white main-sequence star of spectral type A4 at about 58 light years, a relatively near and ordinary hot star marking the hindquarters or rump of Leo, at the top of the triangle that forms the lion's hind parts. The name comes from an ancient Greek word for a girdle or belt, apparently transferred to the star from a different position in the figure at some point in the long transmission of star-names, one of many cases where a traditional name no longer sits where its meaning would suggest.

The girdle-to-rump shift in the star's name is a documented example of what specialists in star nomenclature call transferred names: as figures were redrawn slightly differently by different cartographers over the centuries, a name coined for one part of a constellation's outline could end up permanently attached to a star that, on the current standard figure, sits somewhere else entirely. Zosma's Greek name for a belt or girdle has no connection to the modern astronomical term seismic zone or any related coinage, a coincidence of English homophones rather than any shared etymology worth pursuing. Its comparatively unremarkable astrophysics stands in some contrast to the more storied stars that dominate the rest of this Leo-Cancer-Hydra stretch of the catalogue.