Does millennia-long hibernation await star system after brilliant nova explosion?
A new study is shedding light on a type of binary star system theorized to transition into a state of hibernation lasting thousands of years following powerful nova explosion events. The team focused their attention on a known white dwarf star orbiting closely with a low-mass companion star in the system V1213 Centauri (or Nova Centauri 2009). Star systems such as Nova Centauri 2009, which are the site of some of the brightest explosions known to take place in our galaxy, are known as a classical novae.
Over time, the white dwarf component ofa classical novae siphons hydrogen-rich gas away from its companionstar, and transfers the matter to its surface. This process continuesuntil the white dwarf hits a point of critical mass, after which adramatic thermonuclear nova eruption is inevitable.
These explosions cause the white dwarfsupon which they occur to brighten by a factor of several thousand.Nova explosions, though dramatic and powerful, are not to be mistakenwith supernova events, which often mark the death of a stellar body.
It is thought that white dwarfs inclassic nova systems experience multiple nova explosions with aninterval of anywhere between thousands to millions of years. It ispossible that, several decades after a nova explosion, that the whitedwarf component of a binary system could go into a state ofhibernation, during which time it would transfer barely any matterfrom its companion star. This is known as the hibernation theory.
The long-term observations made usingthe 1.3 m (4.3 ft) Warsaw Telescope located at the Las CampanasObservatory, Chile, appear to support thistheory. Images collected by the telescope between 2003 – 2016seemingly display direct evidence of a transfer of stellar materialprior to the nova explosion, which took place on May 8, 2009, and asignificant brightening of the system following the event.
The increase in Nova Centauri 2009'sluminosity hints that the white dwarf had increased the rate at whichit was feeding off its companion star, seemingly as a direct resultof the nova event. The behavior is in line with predictions madeunder the hibernation model for classical novae systems.
If Nova Centauri 2009 is indeedfollowing the path described under the hibernation theory, it islikely that, over the next decade, that the system's luminosity willgradually fade as the mass transfer rate declines. It is possiblethat following this period of activity, Nova Centauri 2009 could slipinto a hibernation lasting thousands of years. Upon awakening, thestar would experience another nova event, thus beginning the cycleanew.
The team believes that its researchwill provide a solid basis for extensive follow-up observations thatcould support, or throw in to question, standing theories on theevolution of these classical novae systems.
Source: University of Warsaw