Which of the following constellations contains the Cas A supernova remnant?

The Cas A supernova remnant is located within the constellation of Cassiopeia. This remnant is one of the youngest and brightest examples of a supernova explosion in our galaxy, having resulted from a stellar event that occurred approximately 340 years ago, visible from Earth around 1680. Cassiopeia is an easily recognizable constellation in the northern sky, characterized by its distinctive 'W' shape formed by five bright stars.

The connection between Cas A and Cassiopeia is significant because the remnant provides valuable insights into the lifecycle of massive stars, the processes of nucleosynthesis, and the effects of supernova explosions on surrounding interstellar matter. Observations of Cas A have contributed extensively to our understanding of cosmic phenomena.

In contrast, the other constellations listed—Ophiuchus, Pegasus, and Scorpius—do not contain Cas A. While each of these constellations has its own notable celestial features and objects, none are associated with this particular supernova remnant, which is specifically aligned with the region of Cassiopeia in the sky.