New research indicates that the enigmatic Southern Ring Nebula is a product of at least four stars. The presence of these celestial bodies explains why nebular structures are still being carved out. The nebula itself is a result of the death of the star in its center.
"We were surprised to find evidence of two or three companion stars that probably hastened its death as well as one more 'innocent bystander' star that got caught up in the interaction," claims researcher Orsola De Marco of Macquarie University in Australia.
Nebular structures like this one form as the result of the death of a star, when the latter starts to run out of fuel for nuclear fusion. When this happens, the star expands to several hundred times its original size and becomes a red giant. When it completely runs out of fuel, the core of the star collapses into a white dwarf, while the outer material is ejected into space.
The Southern Ring Nebula is the death shroud of a star that now is a white dwarf in the center of the nebula. However, the nebula structure seemed sort of abnormal to scientists and they wanted to study it properly. A closer look showed that there are more stars involved in the nebular structure.
"Once we saw the jets, we knew there had to be another star or even two involved at the center, so we believe there are one or two very close companions, an additional one at middle distance and one very far away. If this is the case, there are four or even five objects involved in this messy death," Orsola de Marco claims.
The study also allowed researchers to calculate the white dwarf's temperature. It is burning at about 110,000 degrees Celsius.