The two stars are separated by 0.047° on the sky, which is equal to 2.82 arc-minutes and thus closer than the usual naked-eye resolution limit of 4 arc-min, giving an elongated appearance of the two together. Both are members of the Pleiadesopen star cluster (M45) and approximately 440 light-years from the Sun.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[5] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[6] It approved the name Asterope for 21 Tauri on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[4]