SN 2002cx

SN 2002cx is a peculiar Type Ia supernova, the prototype of a subclass sometimes referred to as Type Iax supernovae. Unlike typical Type Ia supernovae, which are thought to result from the complete thermonuclear disruption of a white dwarf star reaching the Chandrasekhar limit, SN 2002cx and its kin are thought to represent a failed deflagration or a partial thermonuclear explosion.

Key characteristics that differentiate SN 2002cx-like supernovae from standard Type Ia supernovae include:

• Lower luminosity: They are significantly fainter than typical Type Ia supernovae.
• Lower ejecta velocities: The material ejected from the explosion travels at much slower speeds compared to standard Type Ia events.
• Unburnt carbon: Spectroscopic analysis often reveals the presence of unburnt carbon in the ejected material, suggesting incomplete combustion.
• Lower nickel production: The amount of radioactive nickel-56 produced, which powers the light curve, is much smaller.
• High rate: Evidence suggests they may be more common than previously thought, potentially making up a significant fraction of all Type Ia supernovae.
• Progenitor survival: Some models suggest the white dwarf progenitor may survive the explosion, albeit in a weakened state. This remains an area of active research and debate.

The exact mechanism behind SN 2002cx-like supernovae is still not fully understood. Various theoretical models have been proposed, including deflagration-to-detonation transitions that fail to completely incinerate the white dwarf, or pure deflagration scenarios that result in only a partial explosion. These supernovae are important for understanding the diversity of Type Ia supernovae and for refining their use as standard candles in cosmology.