ASCA science covered a huge range of objects from nearby stars to the most distant galaxies in the Universe. The primary science themes included:
How were elements created and distributed? Observations of supernova remnants show sites where heavy elements are formed and spread to new star forming nurseries. Observations of clusters of galaxies at different distances (and hence, different times in our Universe's past) show the history of elemental abundances on the largest scales.
What happens to matter in extreme gravities around a black hole? ASCA observed both small, stellar-massed black holes and huge, supermassive black holes. Einstein's General Relativity can be tested by observing matter in nearby binary star systems with a black hole and a companion and by observing distant black holes powering active galactic nuclei.
How is matter heated to X-ray temperatures? By observing nearby stars, ASCA data helps to answer the question of how gases are heated to X-ray temperatures.
To find out more about X-ray astronomy in general and some of the specific objects that astronomers study using X-ray information, visit the main Science page.