"Back in 2009, when we were just starting to understand this class, we predicted these supernovae were produced by a white dwarf and
helium star binary system," said team member Ryan Foley of the University of Illinois at Urbana-Champaign, who helped identify Type Iax supernovae as a new class.
He was also highly skeptical of one of the published conclusions: that the disrupted star was a rare
helium star.
In that version, a neutron star slowly spirals in toward a massive
helium star, eventually colliding and producing a cataclysmic explosion of gamma rays.
Our biggest thrill came with discovery of the orbital period of the strange but wonderful
helium star AM Canum Venaticorum.
After its envelope has been dispersed, a high-mass binary consists of a compact
helium star and one that remains on the hydrogen-burning main sequence.
Some white dwarfs are classified as
helium stars as they have very strong helium lines and weak hydrogen lines [2].
The stellar classes discussed in detail at the conference include R Coronae Borealis stars, extreme
helium stars, Wolf-Rayet central stars of planetary nebulae, white dwarfs, and helium-rich subdwarf O and B stars.
It is thought that the progenitors are either massive
helium stars or a type of very large, very hot stars known as Wolf Rayet stars.
Since the 1940s astronomers have puzzled over the origin of
helium stars, giants much larger and hotter than the Sun but less massive.