Protostars at this point often produce strong hypersonic jets of gas that can span 15 light years or more . Surface temperature reaches 4000 K, internal temperature reaches 5,000,000 K. Evolution of protester slows down as the pressure at the center resists further contraction. The star has a radius that slightly larger than the sun and a temperature that is slightly cooler. The star reaches the main sequence. Note that different mass protostars reach different places on the HR diagram.
Massive stars go to the upper left.
Low mass stars to the lower right. The jets seem to start very close to the star but travel huge distances while remaining amazingly straight. T he molecular outflows can contain as much as 100 times the mass of the sun. It is believed that the jets and outflows form from winds driven off the accretion disks. It is not clear why nature makes the jets and outflows.