Type I supernovae are subdivided into Ia, Ib and Ic.Among them, type Ia supernova comes fromWhite dwarf accretionThe explosion of the companion star material when it reaches a certain mass or the combination of two white dwarfs produces an explosion, which belongs to a thermonuclear explosion supernova;Type Ib and Type Ic supernovae come from the collapse and explosion of iron cores of massive stars in the late period. Because the predecessor star has lost the hydrogen envelope or even the helium envelope before the explosion, the spectrum lacks hydrogen lines, so they are classified as Type I.
