SOLAR SYSTEM

Detailed explanation-1: -But stars are not all the same size. They range from the size of a city, to large enough to swallow half our Solar System! Neutron stars pack a lot of mass into a small volume. They may contain the mass of one or two Suns but are often just 20 to 40 km in diameter.

Detailed explanation-2: -Stars range in size from neutron stars, which can be only 12 miles (20 kilometers) wide, to supergiants roughly 1, 000 times the diameter of the sun. The size of a star affects its brightness. Specifically, luminosity is proportional to radius squared.

Detailed explanation-3: -Explain that the names of the four categories contain information on the sizes of the stars. In general, from smallest to largest are: white dwarfs, main sequence stars, giants and supergiants.

Detailed explanation-4: -But Figer found no stars larger than about 130 solar masses. Mindful of limits to the accuracy of his observations, Figer says that a reasonable upper limit to a star’s mass is about 150 solar masses. He adds that his results indicate there is only a 1 in 100 million chance that stars have no upper limit to their mass.

Detailed explanation-5: -But for all other stars, their sizes are determined by that simple balance: the force from the outward radiation, at the surface, has to equal the inward pull of gravitation. Larger radiation forces means the star swells to larger sizes, with the largest stars of all swelling to billions of kilometers.

Detailed explanation-6: -Stars can be classified by their size. Supergiants are the largest stars and dwarf stars are the smallest. In between supergiants and dwarf stars are the giant stars.