The bipolar Butterfly Nebula NGC 6302
The spherical Abell 39 Nebula
For the first time, a team of astronomers based in Germany has detected the presence of magnetic fields in the central stars of four planetary nebulae. Planetary nebulae are expanding gas shells that remain after Sun-like stars eject their outer layers at the end of their lifetimes. It is a long-standing and unsolved mystery why 80% of all planetary nebulae are not spherical. Theories suggest that magnetic fields play a role in shaping planetary nebulae. The team, led by Stefan Jordan, has now discovered the first direct clue that magnetic fields might indeed create these remarkable shapes.
Planetary nebulae are expanding gas shells that are ejected by Sun-like stars at the end of their lifetimes. Sun-like stars spend most of their lifetime burning hydrogen into helium. At the end of this hydrogen fusion phase, these stars increase their diameter by about a factor of 100 and become “red giant stars”. At the end of the red giant phase, the outer layers of the star are blown away. The ejected gas continues to expand out from the remaining central star, which later evolves into a “white dwarf” when all nuclear fusion has ceased. Astronomers believe that a planetary nebula forms when a fast stellar wind that comes from the central star catches up a slower wind produced earlier when the star ejected most of its outer layers. At the boundary between the two winds, a shock occurs that produces the visible dense shell characteristic of planetary nebulae. The gas shell is excited and lighted up by the light emitted by the hot central star. The light from the central star is able to light up the planetary nebula for some 10 000 years.
The observed shapes of planetary nebulae are very puzzling: most of them (about 80%) are bipolar or elliptical rather than spherically symmetric. This complexity has lead to beautiful and amazing images obtained with modern telescopes. The pictures below compare planetary nebulae with bipolar (left) and spherical (right) shapes.
Jennifer Martin | EurekAlert!
Comet or asteroid? Hubble discovers that a unique object is a binary
21.09.2017 | NASA/Goddard Space Flight Center
First users at European XFEL
21.09.2017 | European XFEL GmbH
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...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine