MessageToEagle.com - Six stars similar to the sun with extraordinary dust belts has been observed by an
international team of scientists using the
Herschel Space Observatory - the largest telescope that was ever launched into space.
These debris disks are not only bigger than the Kuiper Belt but they are extremely cold.
With a temperature of about minus 250 °C they are the coldest debris disks known so far.
Artist's impression of the white dwarf G29-38 and its debris disk. Credit: NASA/JPL-Caltech
"They are the remains of the formation of planets, in which the unused, building materials are collected."
"We were surprised that such cold debris disks exist at all," Alexander Krivov, the lead author of the new study, says.
By way of comparison: The Kuiper Belt is about 70 °C degree warmer, some of the dust disks even reach room temperature.
The six debris disks are mysterious because they are lacking the characteristic dust which is always released
when the rocks collide.
For astronomers like Alexander Krivov debris disks are actually nothing new. Our sun is also orbited by such d
ust belts: the Asteroid Belt and the Kuiper Belt with Pluto being perhaps the most well-known object in it.
"Small dust particles are much hotter than the temperatures observed by us," Krivov says.
According to this, the cold debris disks only consist of bigger but at the same time not-too-big rocks.
The calculations of the scientists suggest that the radius of the particles lies between several millimeters and several
"If there were any bigger objects, the disks would be much more dynamic, the bodies would collide and thereby
generate dust," the Jena professor of astrophysics explains.
Dr. Alexander Krivov from Jena University, Germany. Credit: Jan-Peter Kasper/FSU
The cold debris disks are admittedly a relic of its former planet factory, but the growth to the size of
planets stopped early on - even before bodies the size of asteroids or even dwarf planets could develop.
"We don't know why the development stopped," Krivov says. "But the cold debris disks are proof that such belts
can exist for over billions of years."
At the present time, scientists cannot rule out the possibility that the supposed debris disks could
actually be background galaxies which just happen to be behind the central star.
"Our studies however show that there is a high likelihood we are mostly dealing with real disks," Krivov states.
Other instruments like the radio telescope ALMA in the Chilean Atacama Desert, will help to summerize research
findings regarding the debris disks.