P Cygni profile

A P Cygni profile is a distinctive feature seen in the light spectrum of some stars, characterized by a combination of emission and absorption lines. It indicates the presence of a strong stellar wind, where the star is actively ejecting material into space. The profile shows a bright emission line with a blueshifted absorption component, meaning light absorbed by material moving toward us. This pattern reveals that the star is losing mass through powerful outflows. Named after the star P Cygni, this spectral signature helps astronomers study star winds and mass loss in massive stars.