Stars have different sizes due to their mass and their individual stages during their evolutions, according to the Nova Celestia. Giant stars are particularly varied in size, as they have reached a stage wherein they start fusing helium — once the hydrogen runs out — into heavier elements in their core, causing them to grow larger.Know More
As their mass increases, stars change in size, color, fusion rate and luminosity, according to Sun.org. Stars that are similar to the sun and have a solar mass of one are called G stars. They are characterized by a yellow color and a fusion rate that enables them to live for nearly ten billion years. Smaller stars have lower fusion rates because the temperature and pressure in their cores are lower compared to other stars.
The biggest stars are called O-type stars, which have a solar mass of 150 or more. Due to their high surface temperature, they show a blue color. There are incredibly high temperatures and pressures in their cores, causing them to burn hydrogen very quickly. Even though they have large amounts of hydrogen, it is all used up after a few million year,s which is quite short compared to other stars with longer lives.Learn more about Stellar Astronomy
Stars are mostly made up of hydrogen and helium, with only trace amounts of heavier elements. A star is a massive incandescent ball of plasma held together by its own gravity. The principle process that occurs within a star is the conversion of hydrogen into helium.Full Answer >
Stars begin the formation process in cold clouds, called molecular clouds; eventually, these clouds collapse internally, generating a solar nebula, which shrinks and generates heat, spins and flattens. Following the change in the nebula, stars have distinct shapes and exist independently of their formative clouds. To fully transform into a star, they undergo the process of nuclear fusion, which produces heat and energy sufficient for preventing the further collapse of the nebula, ultimately helping stars expand.Full Answer >
While the sun is a star, not all stars are considered suns. In order to be classified as a sun, any given star must have planets orbiting around it, and not all stars do. However, the sun is not the only star that has planets orbiting it.Full Answer >
The observable universe contains an estimated 6.8 x 10^24, or 6.8 septillion, stars. To reach this estimate, astronomers conducted an exhaustive inventory of the stars in the Milky Way galaxy, made reasonable inferences regarding the stars that cannot be seen from Earth and applied that model to the other galaxies within the universal horizon.Full Answer >