A type of irregularly varying star whose spectrum shows broad and very intense emission lines. T Tauri stars are believed to be very young and have not yet settled onto the main sequence depicted in the Hertzsprung-Russell diagram.

Protostar in the late stages of formation, often exhibiting violent surface activity. T Tauri stars have been observed to brighten noticeably in a short period of time, consistent with the idea of rapid evolution during this final phase of stellar formation.

A young star with a circumstellar disk and a bipolar outflow.

A class of very young, often flaring stars on the verge of reaching the main sequence.

T Tauri stars are a kind of variable star whose brightness varies irregularly. Their spectrum has broad and very intense emission lines, probably indicative of violent surface activity. They may be protostars in the later stages of formation, young stars that are not yet stable main sequence stars in the Hertzsprung-Russell Diagram.

T Tauri stars are a class of variable stars named after their prototype - T Tauri. They are found near molecular clouds and identified by their optical variability and strong chromospheric lines.