NASA probe discovers dead star vaporising a mini 'planet'

Washington, Oct 22: Scientists using NASA's Kepler space telescope -- known as the K2 mission -- have spotted strong evidence of a tiny, rocky object being torn apart as it spirals around a white dwarf star.

This discovery validates a long-held theory that white dwarfs are capable of cannibalising possible remnant planets that have survived within its solar system.

"We are for the first time witnessing a miniature 'planet' ripped apart by intense gravity, being vaporised by starlight and raining rocky material onto its star," said Andrew Vanderburg from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts in a NASA statement.

As stars like our Sun age, they puff up into red giants and then gradually lose about half their mass, shrinking down to 1/100th of their original size to roughly the size of Earth.

This dead, dense star remnant is called a white dwarf.

The discovered devastated object formed from dust, rock, and other materials is estimated to be the size of a large asteroid and is the first planetary object to be confirmed transiting a white dwarf.

It orbits its white dwarf, "WD 1145+017", once every 4.5 hours.

This orbital period places it extremely close to the white dwarf and its searing heat and shearing gravitational force.

A research team led by Vanderburg found an unusual, but vaguely familiar pattern in the Kepler data.

The analysis indicated a ring of dusty debris circling the white dwarf what could be the signature of a small planet being vaporised, the authors noted.

"The eureka moment of discovery came on the last night of observation with a sudden realization of what was going around the white dwarf. The shape and changing depth of the transit were undeniable signatures," explained Vanderburg.

"This discovery highlights the power and serendipitous nature of K2.

"The science community has full access to K2 observations and is using these data to make a wide range of unique discoveries across the full range of astrophysics phenomena," said Steve Howell, K2 project scientist in a paper published in the journal Nature.

IANS