The north star is a star that is located almost due north and is useful for navigation. Polaris is currently the pole star of the Northern Hemisphere. A nova is a white dwarf star that suddenly increases in brightness by several magnitudes. It fades very slowly. Suns are powered by nuclear fusion, mostly converting hydrogen into helium .
Nucleosynthesis takes place in stars.
The nucleus is the frozen center of a comet's head. The nucleus contains most of the comet's mass. As stated in our privacy policy , we fully respect your privacy and will not use your e-mail address for any purpose other than the newsletter subscription.