A type Iax supernova is a rare subtype of type Ia supernova, which leaves behind a remnant star, known as zombie star, rather than completely dispersing the white dwarf.[1][2][3][4][5] Type Iax supernovae are similar to type Ia, but have a lower ejection velocity and lower luminosity.[6] Type Iax supernovae may occur at a rate between 5 and 30 percent of the Ia supernova rate. As of October 2014, thirty supernovae had been identified in this category.[7]
In a binary system consisting of a white dwarf and a companion star, the white dwarf strips away material from its companion. Normally the white dwarf would eventually reach a critical mass, and fusion reactions would make it explode and completely dissipate it, but in a Type Iax supernova, only a part of the dwarf's mass is lost.[8]
^McCully, Curtis; Jha, Saurabh W.; Foley, Ryan J.; Bildsten, Lars; Fong, Wen-fai; Kirshner, Robert P.; Marion, G. H.; Riess, Adam G.; Stritzinger, Maximilian D. (7 August 2014). "A luminous, blue progenitor system for the Type Iax supernova 2012Z". Nature. 512 (512): 54–56. arXiv:1408.1089. Bibcode:2014Natur.512...54M. doi:10.1038/nature13615. PMID25100479. S2CID4464556.