SN 2006X

SN 2006X was a Type Ia supernova discovered in the galaxy Messier 100 (M100, NGC 4321) in the constellation Coma Berenices. It was notable because of pre-explosion images obtained by the Hubble Space Telescope (HST) which showed the progenitor system. These pre-explosion images provided rare direct evidence supporting the single-degenerate scenario for Type Ia supernovae.

The single-degenerate scenario posits that a Type Ia supernova occurs when a white dwarf star accretes matter from a companion star, typically a red giant or main sequence star, eventually reaching the Chandrasekhar limit (approximately 1.44 solar masses) and triggering a runaway thermonuclear explosion.

The HST images of SN 2006X showed a luminous source at the location of the supernova prior to the explosion. Detailed analysis of the pre-explosion source indicated that it was likely a red giant companion star donating matter to the white dwarf. However, the nature of the progenitor system and the precise mechanism leading to the supernova are still subjects of ongoing research. Alternative explanations and models also exist, and the single-degenerate scenario is not the only proposed explanation for Type Ia supernovae.

The study of SN 2006X has contributed significantly to our understanding of Type Ia supernovae and the various progenitor systems that can give rise to them. Further observations and analysis continue to refine our knowledge of these important cosmic events, which are crucial for understanding the expansion of the universe and as standardizable candles for measuring cosmological distances.