What type of star is the Sun classified as?

The Sun is classified as a G-type main-sequence star, also known as a G dwarf star. This classification is based on its temperature, size, and luminosity. The "G" refers to the temperature category of the star, which is characterized by a surface temperature between approximately 5,300 and 6,000 degrees Celsius. This temperature allows the Sun to emit a significant amount of visible light and heat, which is crucial for life on Earth.

Main-sequence stars are those that are in a stable phase of stellar evolution, wherein they are fusing hydrogen into helium in their cores. This fusion process generates the energy that powers the star and produces the light we see. The Sun has been in this stable phase for about 4.6 billion years and will remain in this phase for several billion more years until it exhausts its hydrogen fuel, ultimately transforming into a red giant.

The other options, such as red giant, white dwarf, and supernova, describe different stages and types of stellar evolution that do not apply to the current state of the Sun. The classification as a G-type main-sequence star accurately reflects the Sun's characteristics and its position in the lifecycle of stars.