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.”
Read more about this fascinating story at:
Image Credit:
University of Warwick/Mark Garlick
No comments:
Write comments