What is the difference between a star and a protostar?

Answer 1

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 2

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.

Answer 3

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.