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Very old white dwarf discovered with its rings

Credit: Goddard Space Flight Centre, NASA / Scott Wiessinger

Astronomers are looking into the recent discovery of a white dwarf surrounded by rings. This very old star corpse should have already absorbed its surrounding matter.  Yet this is not the case.  Could this be a disturbing glimpse into our sun’s future? 

Stellar evolution

When solar stars starts to age they start to swell.  With all it’s fuel used up, the star becomes a red giant that absorbs the nearest planets in it’s path and stretches out to those farthest off. After this the star dies.  All that remains is it’s core which is dense and hot.  This sort of stellar corpse us called a white dwarf.  A real gravitational chaos can sometimes be present around some of these dwarfs.  Surviving objects collide, and matter is sent back to the white dwarf.  The dwarf then finds it is torn by tidal forces which is why rings appear.

This will probably be our sun’s destiny in about 5 billion years time.  However the rings of dust don’t stay forever.  As time passes, more matter is absorbed by the main object as is the case with Saturn. As a result Saturn’s rings will not always be there.  The same can be said about white dwarfs.  Normally, or at least according to this theory, these rings of matter will not last longer than about 100 million years.  However a recent discovery has just upturned this commonly held belief.

Very old corpse

A team of researchers have announced that they have identified a ringed, white dwarf that is surprisingly old.  The object which is called J0207 and situated about 145 light years from Earth in the constellation of Capricorn has apparently been in this state for almost 3 billion years.  Although this is not the only white dwarf discovered with a ringed system, it is however by far the oldest ever discovered.

The author of the new study John Debes say in a statement that “This white dwarf is so old that whatever process is feeding material into its rings must operate on billion-year timescales,”  The researcher went on to explained that, “Most of the models scientists have created to explain rings around white dwarfs only work well up to around 100 million years, so this star is really challenging our assumptions of how planetary systems evolve.”

The discovery of this unique system of rings might mean that existing models need to be rewritten.  Future follow up studies using orbiting telescopes like the James Webb Telescope could one day give us a better look.

James Webb télescope spatial
James Webb Telescope,which should be launched in 2021. Credits : Wikimedia Commons/Kevin Gill

Make your own discoveries

It is important to mention that this discovery couldn’t have been possible without the Backyard Worlds : Planet 9 project that was set up by NASA.  The idea of the project was to involve the general public to look for abnormalities in the information collected by WISE.  In the beginning the project aimed to detect the possible presence of planet 9 at the outskirts of our solar system, but the discovery of other object was also possible.  This is what happened with this white dwarf as it was discovered in the first instance by the German citizen, Melina Thévenot.

We set up Backyard Worlds: Planet 9 project primarily to research into brown dwarfs and look for new planets in our Solar System,” explained Marc Kuncher, an astrophysicist from the Goddard Space Flight Center from NASA.  “However working scientists from the general public always surprises you. They are impossible to satisfy – the project has just celebrated its second birthday and has already discovered more than 1,000 potential brown dwarfs. We look forward to even more exciting discoveries.”


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