A star consumes quite a lot of hydrogen in its life, and is pretty much "vacuuming" everything in its vicinity. After it dies (eventually by supernova which will spread all its composition over light ...
How can a pre-main sequence star radiate more energy by gravitational contraction than a main-sequence star can by hydrogen fusion?
What particularly causes the T Tauri star to eject the strong bipolar wind which clears the gases around the star?
What is the timescale of start of nuclear fusion as T Tauri type star transforms into a Main Sequence star? Wikipedia article on T Tauri type stars mentions: Their central temperatures are too ...