A T Tauri star refers to a type of young, pre-main-sequence star in its early stages of evolution. The name of these stars is derived from their prototype, T Tauri, which is located in the Taurus constellation. T Tauri stars are commonly found in regions of active star formation, such as stellar nurseries and molecular clouds.
The defining characteristic of a T Tauri star is the presence of intense and variable emission lines in its spectrum, caused by the interaction between the star's powerful stellar winds and its surrounding circumstellar material. These stars are typically low-mass, with a range of spectral types from late F to mid-M, and have yet to enter the stage where hydrogen fusion occurs in their cores.
During their early formation, T Tauri stars undergo rapid contraction and exhibit erratic brightness variations, referred to as "light curves." They often display strong magnetic fields, which can give rise to phenomena like flares and enhanced emission at X-ray wavelengths.
T Tauri stars are obscured by circumstellar disks composed of gas and dust, which play a crucial role in the formation of planetary systems, representing crucial stages in planet formation. These disks are responsible for the eventual accretion of material onto the star and serve as the reservoir for future planetesimals and protoplanets.
In conclusion, T Tauri stars are young, low-mass stars found in stellar nurseries, displaying intense emission lines, erratic brightness variations, strong magnetic fields, and surrounded by circumstellar disks. They serve as important objects for studying the early stages of star and planetary system formation.
