A pre-main-sequence star with mass between 1.5 and 10 times that of the Sun and intrinsically very luminous. HAeBe stars are the intermediate-mass counterparts of the more common T Tauri stars. Being more massive than T Tauri stars, they are of earlier spectral type, B, A, or F. Like the classical T Tauri stars their spectra contain emission lines, especially the hydrogen Balmer series. The existence of P Cygni line profiles indicates mass outflow from the system. Excess infrared and millimetre emission shows that HAeBe stars are associated with abundant circumstellar dust. Significant variations in brightness indicate the existence of clumps in the dust, possibly protoplanets or planetesimals. More than 80% of HAeBe stars are thought to be in binary systems. They are named after the American astronomer George Howard Herbig (1920–2013) who first described them in 1960.