"These tiny relics, a millionth of a meter small, could point us to the first steps of dust formation in both old and young stars," stated Dr. Larry Nittler of the Carnegie Institutions Department of Terrestrial Magnetism. Nittler is co-author of a study published in the September 3, 2004, issue of Science,* about the origin of two presolar grains from the Tieschitz meteorite and the implications they have for resolving observational and theoretical challenges of dusty outflows surrounding asymptotic giant branch (AGB) stars--one of the last evolutionary stages of low-mass stars like the Sun.
Both theoreticians and observational astronomers have long grappled with the issue of whether aluminum oxide--which in its crystalline form is the second hardest natural material--is the first solid to condense as hot, gaseous winds from oxygen-rich AGB stars expand and cool. "Because AGB stars are the most significant source of dust in the Milky Way galaxy, determining how and in what form this dust condenses is important to understanding how the chemical elements get cycled between stars and interstellar space. Also, the first solids in cooling disks around new stars form by analogous processes to those occurring around AGB stars, so these grains give us a glimpse into the earliest stages of our own solar system formation," said Nittler.
Observational astronomers have obtained telltale infrared spectra from dusty AGB stars that have indicated the possible presence of two forms of aluminum oxide--the crystalline form and an amorphous, or non crystalline form. However, the data have not been precise enough to tell if both forms are really present. "This study is really the first definitive analysis that indicates that both forms are indeed produced in AGB stars," said Professor Tom Bernatowicz of Washington University in St. Louis.
Igniting a solar flare in the corona with lower-atmosphere kindling
29.03.2017 | New Jersey Institute of Technology
NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences