Supernova Remnants

Chandra image of Cassiopeia A (NASA/CXC/MIT/UMass Amherst/M.D.Stage et al.)

A Chandra observation of the supernova remnant Cassiopeia A (Cas A) clearly shows both the outer shock wave and the debris heated by the reverse shock wave. The study of supernova remnants with radio, infrared, optical and X-ray telescopes enables astronomers to trace the progress of the shock waves and distribution of elements ejected in the explosion. These data are especially significant because supernovas are the primary means for seeding the galaxy with many elements such as carbon, nitrogen, oxygen, silicon and iron that are necessary for planets and life.

In core-collapse supernovas a rapidly spinning neutron star, or pulsar, can produce a pulsating source of radiation and a magnetized nebula of high-energy particles that lights up the interior of the expanding shell. The Crab Nebula, a remnant of a supernova observed in 1054 A.D., is the most spectacular example.

Chandra image of Crab Nebula (X-ray: NASA/CXC/ASU/J.Hester et al.; Optical: NASA/ESA/ASU/J.Hester & A.Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R.Gehrz)

Chandra's image of the Crab Nebula reveals rings and jets of high-energy particles that appear to have been flung outward over great distances from the neutron star. The diameter of the inner ring is about 1,000 times the diameter of our solar system.

Chandra has been able to detect numerous pulsars and their associated pulsar nebulas. These discoveries are proving to be one of the best ways to identify supernova remnants produced by the core collapse of a massive star, and to distinguish them from remnants produced by the thermonuclear disruption of a white dwarf star (Type Ia supernova).

Chandra image of Tycho's Supernova Remnant (NASA/CXC/Rutgers/J.Warren & J.Hughes et al.)

Another method used to determine the origin of a particular remnant is to study the relative amounts of various elements, especially oxygen and iron. Core-collapse supernovas are rich in oxygen, whereas thermonuclear supernovas produce relatively more iron. The remnants of Tycho's and Kepler's supernovas are thought to have been produced by Type Ia supernovas.

Chandra Podcast: Supernovas: When Stars Die Chandra Podcast: Until Their Dying Day: Stars on the Brink Chronicle Article: Blasts From The Past Impact Science Chandra Images: Supernovas & Supernova Remnants Printable Field Guide: Supernovas & Supernova Remnants Questions & Answers: Supernova Remnants and Neutron Stars