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 Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH

nachricht Spin liquids − back to the roots
22.06.2017 | Universität Augsburg

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

New 3-D display takes the eye fatigue out of virtual reality

22.06.2017 | Information Technology

New technique makes brain scans better

22.06.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>