What is the difference between a nova and a supernova?
The name "nova" means "new" in Latin. In astronomy it's used to describe an object that suddenly shines much more brightly than it had before. Novae occur in multiple star systems in which a white dwarf, neutron star, or even black hole draws gases from the outer atmosphere of a companion star into an envelope of matter around itself.
As more matter is piled on, the gas becomes increasingly hot and dense, until the sudden onset of hydrogen fusion in the envelope triggers an enormous thermonuclear explosion. The star's brightness increases by one million-fold -- enough to make it as luminous as the brightest stars.
A supernova, on the other hand, is the big explosion that accompanies the death of a massive star. In the last stage of its life, a large star fuses lighter elements into iron in its core, which ultimately collapses on itself. As the star's falling atmosphere collides with its ultra-dense core, the resulting rebound rips the star apart in an explosion of unparalleled proportions.
Supernovae produce a 100 million-fold increase in the luminosity of the parent star -- sufficient to see in broad daylight in some cases.
» FAQs about StarDate Online
Stars and Nebulae Links
StarDate's Black Hole Encyclopedia
Stars and Constellations
Virtual Trips to Black Holes and Neutron Stars
|
  |
Contact | About | Friends of McDonald | Sign up for Sky Tips
