A Brown Dwarf
See related question
Hydrogen is the element that is most likely to undergo nuclear fusion.
through the process of fusion, it becomes a star: the birth of the star is the start of fusion. therefore, it is after fusion that it is classified as a star.
The nuclear fusion of hydrogen into helium
When the core of a protostar has reached about 10 million K, pressure within is so great that nuclear fusion of hydrogen begins, and a star is born.
The core of the protostar reached an extremely high temperature
The basic idea is that the protostar contracts, under the influence of gravity, until it gets dense and hot enough to undergo nuclear fusion. You can find more details at the Wikipedia article "Protostar".
Hydrogen is the element that is most likely to undergo nuclear fusion.
through the process of fusion, it becomes a star: the birth of the star is the start of fusion. therefore, it is after fusion that it is classified as a star.
A protostar; also a brown dwarf.
nuclear fusion
The nuclear fusion of hydrogen into helium
the nuclear fusion of hydrogen into helium
That sounds like the description of a protostar.
A protostar is a star the is developing as is on the way to starting nuclear fusion. A brown dwarf is a failed star, one that failed to gather enough mass to start fusion.
When the core of a protostar has reached about 10 million K, pressure within is so great that nuclear fusion of hydrogen begins, and a star is born.
The core of the protostar reached an extremely high temperature
Nuclear fusion. In the case of stars, it is often called nucleosynthesis.