kosmilise udukogu kokkutõmbumisel tekkiv kerajas tihend, mis kujuneb täheks
very young star that is still gathering mass from its parent molecular cloud
Hea teada
See also: 'Protostar'. Swinburne University of Technology, COSMOS - The SAO Encyclopedia of Astronomy > P, http://astronomy.swin.edu.au/cosmos/P/Protostar [19.6.2017]
A star will live the majority of its live in the main sequence phase. This is where nuclear fusion of hydrogen into helium is happening in its core, and the light pressure of this energy balances out the gravitational collapse of the star. Before a star gets into the main sequence phase, though, it spends some time as a protostar – a baby star.
