thumb|A 160 year long [[Photometric system#Photometric letters|visual band light curve for T Tauri, the prototype for the class, plotted from AAVSO data]]
T Tauri stars (TTS) are a class of variable stars that are less than about ten million years old. It ends when a star of or larger develops a radiative zone, or when a smaller star commences nuclear fusion on the main sequence.
History
While T Tauri itself was discovered in 1852, the T Tauri class of stars were initially defined by Alfred Harrison Joy in 1945.
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- Discussion of V471 Tauri observations and general T-Tauri properties, Frederick M. Walter, Stony Brook University, April 2004
- An empirical criterion to classify T Tauri stars and substellar analogs using low-resolution optical spectroscopy, David Barrado y Navascues, 2003