Nebula’s Twin Stars – The most unique and the heaviest white dwarfs ever spotted!Chris Middlebrooks (Author) Published Date : Feb 10, 2015 09:49 IST
For the first time in the history of the universe, two of the heaviest white dwarfs ever discovered are on their way of uniting with each other.
In order to reignite and blow up into a supernova, a white dwarf needs to put on mass by seizing matter from the associate star or by blending with it but in that case the other star also has to be a white dwarf.
The two stars residing around the nebula clarifies the strange shape which is called Henize 2-428. This shape is the release of gas which is leftover when the stars died and turned into white dwarfs.
According to a report in the journal Nature, this discovery was made with the help of the Very Large Telescope located in Atacama Desert Chile as well as ones in the Canary Islands and South Africa.
An astronomer of the European Southern Observatory (ESO) operating in Chile and a co-author of the paper, Dr. Henri Boffin has stated, When we looked at this object's central star with ESO's Very Large Telescope, we found not just one but a pair of stars at the heart of this strangely lopsided, glowing cloud.
The primary reason for the research was to clarify the prominent, asymmetrical forms caused by the so called planetary nebulae , a misnomer dating back to the 18th century b William Herschel.
After intense research, Dr Boffin and his team has found out the mass and the partition of the two stars. What they realized was this is something absolutely distinctive and unusual.
These white dwarfs weigh as much as our sun while orbiting each other in 4.2 hours. On the basis of Einstein s general relativity, they are meant to spiral close to one another while draining energy as gravitational waves and eventually blending into one star with an estimated mass that is 1.8 times of the Sun itself.
This mass is momentous since it exceeds the Chandrasekhar limit, where a white dwarf exceeding the 1.4 solar mass limits will just not persist to cool off. Eventually too much pressure is put at the carbon on the core and this compression ignites nuclear fusion to start up again resulting the dwarf to explode into a Supernova. The Chandrasekhar limit is a boundary named after Subrahmanyan Chandrasekhar, a Nobel Prize winning astrophysicist.
The researchers also debate that this Supernova is anticipated to be of type la in about 700 million years. This indicates that a nuclear fusion reaction on the run swarming with carbon will sooner or later propels the star into pieces.
Until now, the formation of supernovae Type Ia by the merging of two white dwarfs was purely theoretical, said Dr David Jones, a research fellow at ESO and another of the report's authors. The pair of stars in Henize 2-428 is the real thing!
This kind of a supernova is said to be so bright, that even with a distance of 4,000 light years, it can still be noticed from Earth during broad daylight.
Although, an astrophysicist at the University of Oxford, Dr Philipp Podsiadlowski, said the new findings could not discard an additional prospect - a core-collapse supernova which leaves back a dense neutron star after a small explosion.
There's a big debate going on in the community - whether the merger of two massive white dwarfs produces a type Ia or a core-collapse supernova, said Dr Podsiadlowski.
Both of them are interesting! Nevertheless, the results are an important step forward. he added.
What it does tell us is that these massive white dwarf binaries actually exist - even though they were theoretically predicted, that actually hadn't been confirmed.
Nebula’s Twin Stars – The most unique and the heaviest white dwarfs ever spotted!