This artist's conception shows the suspected progenitor of a new kind of supernova called Type Iax. Material from a hot, blue helium star at right is funneling toward a carbon/oxygen white dwarf star at left, which is embedded in an accretion disk. In many cases the white dwarf survives the subsequent explosion. (Photo : Christine Pulliam (CfA))
Supernovae, some of the most powerful pieces of artistry in the heavens, have long been shrouded in mystery despite their relatively bright nature. A new study published in The Astrophysical Journal states that we knew even less about them than we thought - there are three types of supernovae, not just two.
Supernovae have been classified into two categories: a core-collapse supernova, or a Type la supernova. A core-collapse stems from a large star, even more massive than our sun, collapsing unto itself. Type la supernovae usually involve binary star systems with a white dwarf star that is destroyed during the process. The new category, Type lax, involves a binary star system and a white dwarf as well, but is rather unique due to the fact that the white dwarf doesn't have to be obliterated.
In fact, a Type lax supernova can almost be looked at as a "partial" (my own words here) supernova. The white dwarf star survives, whereas in a Type la it doesn't.
"At least some of the time, this explosion will not disrupt the WD (white dwarf)," reads the study abstract.
A Type lax supernova happens when a white dwarf star collects helium from its companion binary star. Researchers aren't sure what the exact reason for ignition is, but the white dwarf seems to be able to survive it. The reason that these types of supernovae haven't been readily observed before is that they are incredibly faint - around one-hundredth of a Type la supernovae - and seem to be only one-third as frequently occurring as Type la supernovae.
The 25 Type lax supernovae observed did not take place in old star-filled elliptical galaxies, hinting that this type of supernova is found only in young star systems.
"The closer we look, the more ways we find for stars to explode," Mark Phillips, one of the researchers involved in the study, said.
You can read the full published study in The Astrophysical Journal.