Eventually, a main sequence star burns through the hydrogen in its core, reaching the end of its life cycle. At this point, it leaves the main sequence.

Both of these are subclasses of the broader category, main sequence stars. The Lifecycle Of A Star. The galaxy was once nothing but a vast cloud of hydrogen, a little helium and lithium, ...

The Sun is very much a main sequence star, in the G-type category (G2V to be precise). It’s been fusing hydrogen for 4.6 billion years, but it still has almost three times as much as it has helium.

Many main sequence stars are also often referred to as “dwarf” stars. They can range greatly in luminosity, color, and size, from a tenth to 200 times the sun’s mass.

During the main sequence phase, nuclear fusion in the core of the star converts hydrogen to helium, and it's when this stock of hydrogen starts to run out that the star moves onto the next stage ...

The First Catalog of Candidate White Dwarf–Main-sequence Binaries in Open Star Clusters: A New Window into Common Envelope Evolution. The Astrophysical Journal , 2024; 976 (1): 102 DOI: 10.3847 ...

But in this case the star is on the main sequence, meaning that it is a normal middle-aged star. The research is published on the arXiv preprint server.

Some stars are off the main sequence, such as white dwarfs and red giants, and don’t fit into this classification system, but these are a topic for another day. Characteristics Of K-type Stars.