What goes on inside the heart of a star? Astronomers have been developing theories about stars inner workings for decades, but evidence to confirm the details of those theories has been sparse.
Figure1: A 5x5 arcminute CCD image of the prototype gravity-mode pulsating subdwarf B star, PG1716+426, and nearby comparison stars. North is up and East is to the left. The subdwarf B star pulsator is the brightest star in the northeast quadrant. The image was taken through an R filter at the University of Arizona Mt. Bigelow 1.6 m telescope and is one of hundreds used to measure the light curve of the star.
Photo Credit: Courtesy of Elizabeth Green of Steward Observatory at the University of Arizona and NSF.
In research supported by NSF, University of Arizona astronomer Elizabeth Green and colleagues have found a new subset of "nearly-naked" stars that dim and brighten due to pulses in their cores. The stars, which may help unlock secrets of advanced stages of stellar evolution, are described in the January 20 Astrophysical Journal Letters.
Chemical and physical changes inside star cores cause the light they emit to pulsate, becoming brighter and dimmer in slowly changing patterns. Analysis of these pulsations would give scientists a better of idea of the processes going on inside stars and help them understand how they change from one type to another. Until now, though, astronomers have been frustrated by the faintness of the pulses.
Roberta Hotinski | National Science Foundation
An international team of physicists a coherent amplification effect in laser excited dielectrics
25.09.2017 | Universität Kassel
Highest-energy cosmic rays have extragalactic origin
25.09.2017 | CNRS
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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25.09.2017 | Physics and Astronomy