NASA
Nasa: Imagine the Universe: Supernovae (Advanced)
Supernovae are divided into two basic physical types, including a description of supernova types and how they are classified based on the existence of hydrogen spectral lines. Definitions of key terms are provided.
NASA
Nasa: Imagine the Universe: Welcome to the World of X Ray Astronomy
Site recounts how X-rays were discovered as well as who discovered them. Offers graphics, links to facts on this topic, a quiz, and teacher resources.
NASA
Nasa: Imagine the Universe: X Ray Binary Stars
Site provides a brief introduction to binary stars. Additional resources for students and teachers on this topic are offered as well as related topics.