"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.
Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa
Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
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23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy