SN 1991T

SN 1991T is a well-studied example of a Type Ia supernova, a powerful stellar explosion resulting from a white dwarf star accumulating material until it reaches a critical point. What makes SN 1991T unique is its unusually bright and slow-evolving light, with distinct spectral features early on that set it apart from typical Type Ia supernovae. This variability helps astronomers understand the different ways these explosions can occur, which in turn improves the accuracy of using supernovae like SN 1991T as "standard candles" for measuring cosmic distances and the expansion of the universe.