A star or sun is a massive spherical space object composed of plasma and gases that produces energy. Stars usually capture other smaller objects in their gravitational field, including planets, moons, comets, or asteroids. The sphere of action of this gravitational force is usually called the star system.

Each star has basic quantities. The most important quantities are mass, stellar size, radiant power, surface temperature and distance from the star Sun (Sol).

There are several different scales for classifying stars, but the Federation most often uses the so-called spectral classification, which is based on the temperature of the photosphere and its corresponding spectral characteristics. There are several spectral classifications, but the most commonly used is probably the Morgan-Keenan spectral classification, which ranks stars by temperature from warmest to coldest. A numerical value in the range from 0 to 9 is also assigned to the basic letter designation, with 0 representing the warmest star in the group and 9 the coldest. Our Sun is a G2 class star.