Astronomers discover coldest ever white dwarf - an ancient diamond the size of the Earth

The galactic oddity is 11 billion years old - the same age as the Milky Way

Astronomers have identified what might be one of the strangest stars in our galaxy: an incredibly cold, ancient and faint white dwarf that has crystallized into a diamond the size of Earth.

“It’s a really remarkable object,” said Professor David Kaplan of the University of Wisconsin-Milwaukee in a press release. “These things should be out there, but because they are so dim they are very hard to find.” 

White dwarfs are stars at the end of their life span when the fusion reaction that has pumped out heat and energy during has all but stopped, leaving the remaining carbon and oxygen to compact into an incredibly dense and cold state.

In the case of this recently discovered white dwarf, astronomers believe that it has cooled and crystallized all the way to diamond, estimating that the once-fiery star is 11 billion years old – making it the same age as the Milky Way.

Stars like this aren’t rare (around 97 per cent of stars are thought to turn into white dwarfs and we've even discovered planets made of diamond) but they are incredibly difficult to find – simply because their light is too faint to make its way through the cosmos to telescopes on Earth.

Thankfully, this particular white dwarf had a partner that gave away its presence to astronomers on Earth: a companion pulsar star dubbed PSR J2222-0137.

Read more: The weiredest planets discovered by Nasa
Newly discovered 'super-Earth' is made of diamonds
Earth's 'underground oceans' three times size of surface

Pulsars are superdense neutron stars that spin incredibly quickly, shooting beams of radio waves into the cosmos like supercharged lighthouses. However, with PSR J2222-0137 astronomers noticed that the radio beams were regularly obstructed by an unknown object.

The team from the National Radio Astronomy Observatory in the US suspected it was a white dwarf, but were still unable to see the object after further observation. Their explanation?  That this is one of the coldest white dwarf ever discovered.

“Our final image should show us a companion 100 times fainter than any other white dwarf orbiting a neutron star and about 10 times fainter than any known white dwarf, but we don’t see a thing,” said University of North Carolina graduate student Bart Dunlap. “If there's a white dwarf there, and there almost certainly is, it must be extremely cold."

However, this is cold in an astronomical sense and despite being 5,000 times cooler than the center of the Sun, the diamond white dwarf is still thought to be 2,700 degrees Celsius (or 4,892 degrees Fahrenheit).

Start your day with The Independent, sign up for daily news emails
Arts and Entertainment
Joe Cocker performing on the Stravinski hall stage during the Montreux Jazz Festival, in Montreux, Switzerland in 2002
musicHe 'turned my song into an anthem', says former Beatle
News
Clarke Carlisle
sport
Sport
footballStoke City vs Chelsea match report
Arts and Entertainment
theatreThe US stars who've taken to UK panto, from Hasselhoff to Hall
PROMOTED VIDEO
ebooks
ebooksA year of political gossip, levity and intrigue from the sharpest pen in Westminster
Life and Style
Approaching sale shopping in a smart way means that you’ll get the most out of your money
life + styleSales shopping tips and tricks from the experts
News
newsIt was due to be auctioned off for charity
News
Coca-Cola has become one of the largest companies in the world to push staff towards switching off their voicemails, in a move intended to streamline operations and boost productivity
peopleCoca-Cola staff urged to switch it off to boost productivity
Environment
Sir David Attenborough
environment... as well as a plant and a spider
Voices
'That's the legal bit done. Now on to the ceremony!'
voicesThe fight for marriage equality isn't over yet, says Siobhan Fenton
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Austen Lloyd: Regulatory / Compliance / Exeter

Excellent Salary: Austen Lloyd: Exeter - An excellent opportunity for a Solici...

Ashdown Group: IT Support Technician - 12 Month Fixed Term - Shrewsbury

£17000 - £20000 per annum: Ashdown Group: IT Helpdesk Support Technician - 12 ...

The Jenrick Group: Maintenance Planner

£28000 - £32000 per annum + pension + holidays: The Jenrick Group: Maintenance...

The Jenrick Group: World Wide PLC Service Engineer

£30000 - £38000 per annum + pesion + holidays: The Jenrick Group: World Wide S...

Day In a Page

Isis in Iraq: Yazidi girls killing themselves to escape rape and imprisonment by militants

'Jilan killed herself in the bathroom. She cut her wrists and hanged herself'

Yazidi girls killing themselves to escape rape and imprisonment
Ed Balls interview: 'If I think about the deficit when I'm playing the piano, it all goes wrong'

Ed Balls interview

'If I think about the deficit when I'm playing the piano, it all goes wrong'
He's behind you, dude!

US stars in UK panto

From David Hasselhoff to Jerry Hall
Grace Dent's Christmas Quiz: What are you – a festive curmudgeon or top of the tree?

Grace Dent's Christmas Quiz

What are you – a festive curmudgeon or top of the tree?
Nasa planning to build cloud cities in airships above Venus

Nasa planning to build cloud cities in airships above Venus

Planet’s surface is inhospitable to humans but 30 miles above it is almost perfect
Surrounded by high-rise flats is a little house filled with Lebanon’s history - clocks, rifles, frogmen’s uniforms and colonial helmets

Clocks, rifles, swords, frogmen’s uniforms

Surrounded by high-rise flats is a little house filled with Lebanon’s history
Return to Gaza: Four months on, the wounds left by Israel's bombardment have not yet healed

Four months after the bombardment, Gaza’s wounds are yet to heal

Kim Sengupta is reunited with a man whose plight mirrors the suffering of the Palestinian people
Gastric surgery: Is it really the answer to the UK's obesity epidemic?

Is gastric surgery really the answer to the UK's obesity epidemic?

Critics argue that it’s crazy to operate on healthy people just to stop them eating
Homeless Veterans appeal: Christmas charity auction Part 2 - now LIVE

Homeless Veterans appeal: Christmas charity auction

Bid on original art, or trips of a lifetime to Africa or the 'Corrie' set, and help Homeless Veterans
Pantomime rings the changes to welcome autistic theatre-goers

Autism-friendly theatre

Pantomime leads the pack in quest to welcome all
The week Hollywood got scared and had to grow up a bit

The week Hollywood got scared and had to grow up a bit

Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

Panto dames: before and after

From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
Thirties murder mystery novel is surprise runaway Christmas hit

Thirties murder mystery novel is surprise runaway Christmas hit

Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

Anne-Marie Huby: 'Charities deserve the best'

Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
The botanist who hunts for giant trees at Kew Gardens

The man who hunts giants

A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there