What is the commonly used name for the cosmic object associated with Mira, the red giant star?

The object associated with Mira, the red giant star, is commonly referred to as a variable star. Mira is particularly notable for its variability in brightness, which is characteristic of certain types of stars that undergo periodic changes in luminosity. In the case of Mira, it is a well-known example of a long-period variable star, with its brightness varying significantly over a cycle of about 332 days. This variability is due to changes in the star's pulsation as it expands and contracts.

Mira's classification as a variable star has made it an important subject of study in stellar dynamics and evolution, helping astronomers understand the life cycles of stars, especially those that evolve into red giants. Other options like pulsars, supernovae, and black holes refer to entirely different types of cosmic phenomena, with distinct physical processes and properties, making them unrelated to the classification of Mira.