Two dead stars are causing an eclipse every seven minutes

• The Zwicky Transient Facility (ZTF) has spotted the fastest 'eclipsing binary system' till date.
  
• Two white dwarf stars are zipping around each other so quickly that its causing an eclipse every seven minutes.
  
• In addition to orbiting each other, they're emitting gravitational waves pushing them closer together.
  

Two white dwarf stars, more or less the same size as the Earth, are circling each other at hundreds of kilometers per second causing an eclipse every seven minutes.

The pair of dead stars — remnants of what used to be a star like our Sun only nine times hotter — have been dubbed as ZTF J1539+5027 and are the fastest 'eclipsing binary system' according to the Zwicky Transient Facility (ZTF).

As they circle each other 8,000 light years from Earth in the Boötes constellation — they're also being pulled closer together.

Inching closer

The pair is noted for being one of the few known sources of gravitational waves in the universe, which is causing the two dead stars to merge. And unlike with other binary star systems, one white dwarf star hasn't eaten up the other yet.

Nonetheless, they're already so close together that the distance between them is one-fifth of the distance between the Earth and the moon. The circumference of their orbit is so small that they could fit inside Saturn at this point, according to ZTF.

Blinking in the night sky

"As the dimmer star passes in front of the brighter one, it blocks most of the light, resulting in the seven-minute blinking pattern we see in the ZTF data," stated Kevin Burdge, lead author of the study published in Nature.

ZTF's 576 megapixel camera caught the stars through its lens during its regular scans of the night sky every three days.

"Sometimes these binary white dwarfs merge into one star, and other times the orbit widens as the lighter white dwarf is gradually shredded by the heavier one," stated James Fuller, one of the co-authors of the study.

The hotter of the two stars is estimated to be burning at around 50,000 degrees Celsius and ordinarily, its assumed that the high temperature is because the hotter star is 'feeding' off its companion. In this case, the 'feeding' or accretion process doesn't seem to be present since the researchers can't spot the associated x-rays.

"We're not sure what will happen in this case, but finding more such systems will tell us how often these stars survive their close encounters," Fuller explained.

Even though the stars are moving closer together, scientists estimate that they will continue to blink in the night sky for another hundred thousand years before finally colliding into each other.

See also:
'Zombie' stars are coming back to life and scientists are on the hunt for more

China made an artificial star that's 6 times hotter than the sun and it could be the future of energy

This insane golden chamber contains water so pure it can dissolve metal, and is helping scientists detect dying stars