Astronomers Discover Planet Fragment That Survived the Destruction of Star
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Image Credit: University of Warwick/Mark Garlick
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Astronomers at the University of Warwick have discovered a fragment of a planet that has survived the death of its host star. Circling over 400 light years away, astronomers detected this small body orbiting a white dwarf much closer than they would have expected.
With an orbit of only two hours, the astronomers were surprised to have discovered this fragment. Believed to have once been part of a larger planet, it is believed that this fragment survived due to its composition of heavy metals.
Using the Gran Telescopio Canarias in La Palma, the scientists were studying a debris disc orbiting a white dwarf that was formed by the disruption of rocky bodies made up of elements such as iron, magnesium, silicon and oxygen. Within this disc, astronomers were able to catch the fragment due to a ring of gas streaming from the body, similar to a comet's tail.
It is estimated that this body is at least a kilometre in size, but it could be as large as a few hundred kilometres in diameter, comparable to some of the largest asteroids in the Solar System.
"The star would have originally been 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 white dwarfs, extremely dense," said lead author Dr. Christopher Manser.
"The white dwarf’s gravity is so strong - about 100,000 times that of the Earth’s - that a typical asteroid will be ripped apart by gravitational forces if it passes too close to the white dwarf.”
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