What is the difference between a star and a protostar?

Answer 1

Oh, dude, a star is like a fully formed celebrity, shining bright and stealing the spotlight in the universe, while a protostar is just a wannabe star going through its awkward phase, trying to get its act together before hitting the big stage. It's like the difference between a seasoned actor and an aspiring newbie still figuring out their lines.

Answer 2

A "Star" can be anything from the beginning of a stars life (Protostar) up until it has died and only it's remnants remain (White dwarf, neutron star, black hole).

However, for this question, we will assume that a "star" is when it is fusing hydrogen into helium, which is what most stars we see, including the Sun are doing.

A protostar is the first stage in a stars life (See related question) whereas a "star" in this question is when there is enough pressure and thus temperature for the star to star fusing hydrogen into helium and it joins the main sequence - thus becoming a star (See related question)

Answer 3

A protostar is a young stellar object in the process of forming into a star through gravitational collapse, while a star is a stable celestial body that has reached a state of nuclear fusion in its core. Protostars are still accumulating mass and have not yet begun nuclear fusion, while stars are actively burning hydrogen into helium in their cores.