Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cosmic Dust Belts without Dust

08.07.2013
An international research team of astrophysicists of Jena University (Germany) has discovered six ultra-cold debris disks - the coldest debris disks known so far. Moreover, the cold debris disks are lacking the characteristic dust which is always released when the rocks collide. The scientists came across the unusual debris disks with the help of the Herschel Space Observatorium.

Planets and asteroids, red giants and brown dwarfs – there are all kinds of objects in our Universe. Debris disks are among them. These are belts consisting of countless dust particles and planetesimals, circling around one central star.

“At least one fifth of stars are surrounded by dust belts like these,“ Prof. Dr. Alexander Krivov from the Friedrich-Schiller-University Jena explains. “They are the remains of the formation of planets, in which the unused, building materials are collected,“ the astrophysicist points out. Therefore debris disks are an important piece in the puzzle to be able to better understand the variety of planetary systems.

For astronomers like Alexander Krivov debris disks are actually nothing new. Our sun is also orbited by such dust belts: the Asteroid Belt and the Kuiper Belt with Pluto being perhaps the most well-known object in it. However, the Jena astrophysicist, accompanied by an international team of scientists, has observed six stars similar to the sun with extraordinary dust belts:

The newly discovered debris disks are not only bigger than the Kuiper Belt. Above all they are extremely cold. With a temperature of about minus 250 °C they are the coldest debris disks known so far. The scientists report on it in the science journal ‘The Astrophysical Journal‘, which is already online and will be available in a print version from 20 July. “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 for yet another reason: They are lacking the characteristic dust which is always released when the rocks collide. “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 kilometers maximum. “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.

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.”

The scientists came across the unusual debris disks with the help of the Herschel Space Observatory – the largest telescope that was ever launched into space. “Herschel was especially designed to detect cold objects, because it has measured the radiation in far infrared,” Prof. Krivov explains. In spite of its enormous effectiveness the observation of the cold debris disks was a demanding task even for Herschel. Thus 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. As planned, Herschel entered retirement in April. The scientists reckon that they will gain final certainty about their findings with the help of data by further instruments like the radio telescope ALMA in the Chilean Atacama Desert.

Original Publication:
Krivov, A.V. et al.: Herschel‘s „Cold Debris Disks“: Background Galaxies or Quiescent Rims of Planetary Systems? The Astrophysical Journal (2013), http://iopscience.iop.org/0004-637X/772/1/32 (DOI:10.1088/0004-637X/772/1/32).
Contact:
Prof. Dr. Alexander Krivov
Astrophysikalisches Institut und Universitätssternwarte der Universität Jena
Schillergässchen 2-3, 07745 Jena, Germany
Tel.: 03641 / 947530
E-Mail: krivov[at]astro.uni-jena.de

Claudia Hilbert | idw
Further information:
http://www.uni-jena.de

More articles from Physics and Astronomy:

nachricht UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire

nachricht NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>