Astronomers just Found Corpse of a Planet like Earth

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A fragment of a planet that survived the death of its parent star was discovered by astronomers at the University of Warwick in the United Kingdom. The "planetary corpse" is located on a disc of debris formed by destroyed and consumed planets.

The planetesimal - a rocky body a few miles away - rich in iron and nickel survived a system-wide cataclysm that followed the death of its host star, called SDSS J122859.93 + 104032.9. 

It is believed to have once been part of a larger planet, and its survival is even more astonishing, as it orbits closer to its star than was thought possible, orbiting it once every two hours.

The discovery, published in the journal Science, is the first time scientists use spectroscopy to discover a solid body orbiting a white dwarf. 

Using the Gran Telescopio Canarias in La Palma, Spain, the scientists studied the disk of debris in the white dwarf 410 light-years away, formed by the rupture of rocky bodies composed of elements such as iron, magnesium, silicon and oxygen.

Inside that disk they discovered a ring of gas flowing from a solid body, like the tail of a comet. This gas can be generated by the body itself or by evaporation of dust as it collides with small debris. 

Astronomers estimate that this body should be at least one kilometer in size, but may be as large as a few hundred kilometers in diameter, comparable to the largest known asteroids in our solar system.

White dwarfs are the remains of stars like our Sun that have burned all their fuel and expelled their outer layers, leaving behind a dense core that slowly cools with time. 

This particular star has shrunk so much that the planetesimal orbits within its original ray. Evidence suggests that it was once part of a larger body, further from its star system, and is likely to have been a torn planet when the star began its death process.

"The star would originally have about two solar masses, but now the white dwarf is only 70% of the mass of our Sun. It is also very small - roughly the size of the Earth - and this makes the star and, in general, all dwarfs white, extremely dense," said Dr. Christopher Manser, a researcher at the Department of Physics.

"The gravity of the white dwarf is so strong - about 100,000 times the Earth's gravity - that a typical asteroid would be torn apart by gravitational forces if it passed very close," he added.

The discovery offers a clue as to how planets can reside in other solar systems and a glimpse of our own future.

"As the stars age, they turn into red giants, which 'clean' much of the inside of their planetary system. In our Solar System, the Sun will expand to where Earth currently orbits and will eliminate nodes, Mercury and Venus," concluded Manser. [ SpaceAnswers ]