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Sonntag, 15. November 2015 - 19:31 Uhr

Astronomie - Mehr als das Auge sieht: Delta Orionis im Gürtel des Orion

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One of the most recognizable constellations in the sky is Orion, the Hunter. Among Orion’s best-known features is the “belt,” consisting of three bright stars in a line, each of which can be seen without a telescope.
The westernmost star in Orion’s belt is known officially as Delta Orionis. (Since it has been observed for centuries by sky-watchers around the world, it also goes by many other names in various cultures, like “Mintaka”.) Modern astronomers know that Delta Orionis is not simply one single star, but rather it is a complex multiple star system. Delta Orionis is a small stellar group with three components and five stars in total: Delta Ori A, Delta Ori B, and Delta Ori C. Both Delta Ori B and Delta Ori C are single stars and may give off small amounts of X-rays. Delta Ori A, on the other hand, has been detected as a strong X-ray source and is itself a triple star system as shown in the artist’s illustration.
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Delta Orionis is a small stellar group with three components and five stars in total: Delta Ori A, Delta Ori B, and Delta Ori C. Both Delta Ori B and Delta Ori C are single stars and may give off small amounts of X-rays. Delta Ori A, on the other hand, has been detected as a strong X-ray source and is itself a triple star system as shown in the artist’s illustration.
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n Delta Ori A, two closely separated stars orbit around each other every 5.7 days, while a third star orbits this pair with a period of over 400 years. The more massive, or primary, star in the closely-separated stellar pair weighs about 25 times the mass of the Sun, whereas the less massive, or secondary star, weighs about ten times the mass of the Sun. 
The chance alignment of this pair of stars allows one star to pass in front of the other during every orbit from the vantage point of Earth. This special class of star system is known as an “eclipsing binary,” and it gives astronomers a direct way to measure the mass and size of the stars.
Massive stars, although relatively rare, can have profound impacts on the galaxies they inhabit. These giant stars are so bright that their radiation blows powerful winds of stellar material away, affecting the chemical and physical properties of the gas in their host galaxies. These stellar winds also help determine the fate of the stars themselves, which will eventually explode as supernovas and leave behind a neutron star or black hole. 
By observing this eclipsing binary component of Delta Orionis A (dubbed Delta Ori Aa) with NASA’s Chandra X-ray Observatory for the equivalent of nearly six days, a team of researchers gleaned important information about massive stars and how their winds play a role in their evolution and affect their surroundings. The Chandra image is seen in the inset box in context with an optical view of the Orion constellation obtained from a ground-based telescope. 
Since Delta Ori Aa is the nearest massive eclipsing binary, it can be used as a decoder key for understanding the relation between the stellar properties derived from optical observations, and the properties of the wind, which are revealed by X-ray emission. 
The lower-mass companion star in Delta Ori Aa has a very weak wind and is very faint in X-rays.  Astronomers can use Chandra to watch as the companion star blocks out various parts of the wind of the more massive star. This allows scientists to better see what happens to the X-ray emitting gas surrounding the primary star, helping to answer the long-standing question of where in the stellar wind the X-ray emitting gas is formed.  The data show that most of the X-ray emission comes from the wind of the giant star, and is likely produced by shocks resulting from collisions between rapidly-moving clumps of gas embedded within the wind. 
The researchers also found that the X-ray emission from certain atoms in the wind of Delta Ori Aa changes as the stars in the binary move around. This may be caused by collisions between winds from the two stars, or from a collision of the wind from the primary star with the surface of the secondary star. This interaction, in turn, obstructs some of the wind from the brighter star. 
Parallel optical data from the Canadian Space Agency’s Microvariability and Oscillation of Stars Telescope (MOST) revealed evidence for oscillations of the primary star produced by tidal interactions between the primary and companion star as the stars travel in their orbits.  Measurements of the changes of brightness in optical light plus detailed analysis of optical and ultraviolet spectra were used to refine the parameters of the two stars. The researchers were also able to resolve some previously claimed inconsistencies between the stellar parameters and models of how the stars are expected to evolve with time.
These results were published in four coordinated papers that were recently published in The Astrophysical Journal led by Michael Corcoran (NASA’s Goddard Space Flight Center & Universities Space Research Association), Joy Nichols (Harvard-Smithsonian Center for Astrophysics), Herbert Pablo (University of Montreal), and Tomer Shenar (University of Potsdam). NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
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Delta Orionis is a complex star system that contains five stars in total.
Credits: X-ray: NASA/CXC/GSFC/M. Corcoran et al.; Optical: Eckhard Slawik
Quelle: NASA

Tags: Astronomie 

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Sonntag, 15. November 2015 - 17:00 Uhr

Raumfahrt - China sucht öffentlich Namen für Dark Matter Explorer Mission-Sonde

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The public will have a chance to name a Chinese dark matter probe satellite expected to be launched by the end of this year.
The competition to name the Dark Matter Particle Explorer (DAMPE) was announced at the Purple Mountain Observatory (PMO) of the Chinese Academy of Sciences (CAS) in Nanjing Tuesday. Entries from any country will be accepted until October 31 and can be submitted online at http://scitech.people.com.cn/DAMPE.
There will be five grand prize winners, 20 first prize winners, 50 second prize winners, 100 third prize winners and 500 memorial award winners. Grand prize winners will be able to watch the satellite launch in person at the Jiuquan Satellite Launch Center.
DAMPE will be the first in a program consisting of five research satellites, and its development is supported by the space science program of CAS, said Chang Jin, chief scientist of the project and PMO researcher.
Scientists believe dark matter exists based on the law of universal gravitation, but have never directly detected it.
Accounting for over a quarter of the universe's mass-energy balance, it can only be observed indirectly through its interaction with visible matter.
Based on the standard model of cosmology, the total mass-energy of the known universe contains 4.9 percent ordinary matter, 26.8 percent dark matter and 68.3 percent dark energy.
Many scientists, including Nobel prize laureate Yang Zhenning, believe that development of dark matter theory might lead to understanding phenomena that can't be explained with current knowledge, triggering "revolutionary progress" in physics.
DAMPE looks like an expensive and complicated four-layer cake turned upside down. It weighs 1.9 tonnes and its payload is 1.4 tonnes. The DAMPE project costs 100 million U.S. dollars and its lifespan is more than 3 years.
DAMPE will observe the direction, energy and electric charge of high-energy particles in space in search of dark matter.
The probe will orbit the earth to study the origin of cosmic rays and observe high-energy gamma rays. Original data from DAMPE could provide solid evidence for the existence of dark matter particles.
DAMPE will have the widest observation spectrum and highest energy resolution of any dark matter probe in the world.
Developers of DAMPE include PMO of CAS, University of Science and Technology of China, Institute of High Energy Physics of CAS, Institute of Modern Physics of CAS, National Space Science Center of CAS, University of Geneva and University of Perugia.
Quelle: Xinhua
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Update: 15.11.2015
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China plant  Dunkle Materie Forschungs-Satelliten Mitte Dezember zu starten
he Dark Matter Particle Explorer (DAMPE) Satellite, developed by the Chinese Academy of Sciences (CAS), is expected to be launched at the Jiuquan Satellite Launch Center in mid-December.
DAMPE, the first satellite in a CAS space science program, and its carrier Long March 2-D rocket left Shanghai Saturday, heading for Jiuquan in northwest China's Gansu Province.
The satellite and carrier rocket are fully prepared for blast-off after passing the inspection and approval of the CAS.
It will be the 26th mission for the Long March 2-D rocket.
DAMPE is one of the first four scientific satellites employed in the CAS space program. It will observe the direction, energy and electric charge of high-energy particles in space in search of dark matter.
DAMPE will have the widest observation spectrum and highest energy resolution of any dark matter probe in the world.
According to experts, DAMPE is designed for increased payload, with the scientific payload weighing 1,410 kg and the whole satellite weighing 1,850 kg.
The design helps cut down on the size and weight of the satellite and save launching costs.
Quelle: Xinhua
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Chinese scientists are planning to send a dark matter probe satellite into space by the end of this year. You could have the opportunity to see the launch at the Jiuquan Satellite Launch Center if you give the satellite a name.
The competition to name the Dark Matter Particle Explorer (DAMPE) from the public was held at the Purple Mountain Observatory (PMO) of Chinese Academy of Sciences (CAS) in Nanjing Tuesday . Entries from any country will be accepted until October 31 and can be submitted via http://scitech.people.com.cn/DAMPE
There will be 5 grand prize winners, 20 first prize winners, 50 second prize winners, 100 third prize winners and 500 memorial award winners. Those who won grand prize will be able to watch the satellite launch by person.
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A part of DAMPE.  picture from the National Space Science Center of CAS
Accounting for over a quarter of the universe's mass-energy balance, it can only be observed indirectly through its interaction with visible matter.
According to the scientists and based on the standard model of cosmology, the total mass–energy of the known universe contains 4.9 percent ordinary matter, 26.8 percent dark matter and 68.3 percent dark energy.
Many scientists, including Nobel prize laureate Yang Zhenning, believe that development of dark matter theory might lead to understanding phenomena that can't be explained with current knowledge, triggering "revolutionary progress" in physics.
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The uncompleted DAMPE.   picture from the National Space Science Center of CAS
The DAMPE looks like an expensive and complicated four-layer cake that stands upside-down. It weighs 1.9 tonnes and its payload weighs 1.4 tonnes. The DAMPE project costs 100 million U.S. dollars and its lifespan is over 3 years.
The DAMPE will observe the direction, energy and electric charge of high-energy particles in space in search of dark matter.
The probe will orbit the earth 500 above ground and study the origin of cosmic rays and observe high-energy gamma rays. If DAMPE finds original data that provides certain proof, scientists will have solid evidence for the existence of dark matter particle.
The DAMPE will have the widest observation spectrum and highest energy resolution of any dark matter probe in the world.
Developers of the DAMPE include PMO of CAS, University of Science and Technology of China, Institute of High Energy Physics of CAS, Institute of Modern Physics of CAS, National Space Science Center of CAS, University of Geneva and University of Perugia.
Quelle: iCrossChina

Tags: Raumfahrt 

1658 Views

Sonntag, 15. November 2015 - 15:00 Uhr

Raumfahrt-History - NASA-flickr-Archiv: Apollo-14 Teil-3

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Fotos: NASA


Tags: Raumfahrt 

1356 Views

Sonntag, 15. November 2015 - 13:00 Uhr

Raumfahrt-History - NASA-flickr-Archiv: Apollo-14 Teil-2

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Fotos: NASA


Tags: Raumfahrt 

1374 Views

Samstag, 14. November 2015 - 23:00 Uhr

Astronomie - Weitere Tauriden-Feuerkugeln über Österreich

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Quelle: Hermann Koberger / Österreich


Tags: Astronomie 

1630 Views

Samstag, 14. November 2015 - 22:00 Uhr

Raumfahrt-History - NASA-flickr-Archiv: Apollo-14 Teil-1

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Fotos: NASA


Tags: Raumfahrt 

1384 Views

Samstag, 14. November 2015 - 17:46 Uhr

Astronomie - Hubble Sicht auf eine einsame Galaxie

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Only three local stars appear in this image, quartered by right-angled diffraction spikes. Everything besides them is a galaxy; floating like a swarm of microbes in a drop of water, and brought into view here not by a microscope, but by the Advanced Camera for Surveys on the Hubble Space Telescope.
In the foreground, the spiral arms of MCG+01-02-015 seem to wrap around one another, cocooning the galaxy. The scene suggests an abundance of galactic companionship for MCG+01-02-015, but this is a cruel trick of perspective. Instead, MCG+01-02-015’s unsentimental naming befits its position within the cosmos: it is a void galaxy, the loneliest of galaxies.
The vast majority of galaxies are strung out along galaxy filaments — thread-like formations that make up the large-scale structure of the universe — drawn together by the influence of gravity into sinuous threads weaving through space. Between these filaments stretch shallow but immense voids; the universe’s wastelands, where, outside of the extremely rare presence of a galaxy, there is very little matter — about one atom per cubic meter. One such desolate stretch of space is what MCG+01-02-015 reluctantly calls home.
The galaxy is so isolated that if our galaxy, the Milky Way, were to be situated in the same way, we would not even have known of the existence of other galaxies until the development of strong telescopes and detectors in the 1960s.
Image credit: ESA/Hubble & NASA and N. Gorin (STScI), Acknowledgement: Judy Schmidt
Text credit: European Space Agency
Quelle: NASA

Tags: Astronomie 

1627 Views

Samstag, 14. November 2015 - 17:30 Uhr

Raumfahrt - Bremen wird zum Mekka der Raumfahrtexperten

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Vom 17. bis 19. November 2015 findet in Bremen erstmals die Space Tech Expo Europe & Conference statt.  Zu den weit über 200 internationalen Austellern gehört das Who is Who der europäischen Luft- und Raumfahrtindustrie. Bei der Konferenz werden führende Experten aus Europa und aus Übersee über die aktuellen Trends der Raumfahrt diskutieren.
Die Space Tech Expo Europe stellt ein Forum für Experten der Entwicklung, Herstellung und Prüfung von Raumfahrzeugen, Satelliten, Trägerraketen und Raumfahrttechnologien dar und ist in dieser Form auf unserem Kontinent neu. Sie wird damit Europas größte Fachmesse, die auf die Lieferketten und Technik für Raumfahrzeuge, deren Teilsysteme und Bauteile spezialisiert ist. Die Grundidee dazu stammt aus den USA, wo sich die Veranstaltung nach nur vier Jahren zur wichtigsten Raumfahrtmesse der US-Westküste und einem der größten Branchentreffen der Welt entwickelt hat.
Hochkarätige Diskussionen auf der Konferenz
Die Messe ist mit einer dreitägigen Konferenz gekoppelt, wo führende Techniker, Geschäftsführer und globale Entscheidungsträger aus Industrie, Wissenschaft, Politik und Militär die Trends der Raumfahrttechnologie diskutieren und in kleineren Gesprächsrunden drängende Fragen ihrer Fachgebiete klären können. Ein Schwerpunkt wird dieses Jahr die Entwicklung bei Mini-Satelliten sein, die immer mehr anspruchsvolle Aufgaben übernehmen und dabei noch kostengünstig sind.
Die Konferenz ist in zwei Teile gegliedert, das Industrie-Forum und das Technologie-Forum. Auf dem Technologie-Forum wird sich neben weiteren Experten Stefano Bianci, Direktor des Launchers Development Department  der ESA, mit der Zukunft der europäischen Trägerraketen und deren Weiterentwicklung auseinandersetzen.
Das Industrie-Forum beschäftigt sich neben der Kommerzialisierung der Raumfahrtaktivitäten als ein Schwerpunkt auch mit dem Technologietransfer. Dazu wird Frank Salzgeber von der ESA die Arbeit des Technology Transfer Program Office der ESA vorstellen und Alessandro Donati vom ESOC in Darmstadt über die Nutzung von Satellitentechnologien bei der Luftfahrt und maritimen Sicherheit sprechen.
Eine besondere Form intensiven Gedankenaustauschs ermöglicht das B2B Matchmaking, wo sich Teilnehmer der Expo in kleinen Gesprächsrunden, die nicht länger als 20 Minuten dauern dürfen, zusammenfinden können. Veranstaltet wird diese Kooperationsbörse vom Enterprise Europe Network. Für das Bremer Matchmaking haben sich bereits über 250 Teilnehmer aus rund 25 Ländern angemeldet.
Bremen – ein idealer Standort
Bremen bietet sich für diese Veranstaltung als ein idealer Standort an. In der Hansestadt gibt es eine lange Tradition der Luft- und Raumfahrtindustrie. Weltbekannte Unternehmen wie die Airbus Group oder OHB SE sind hier angesiedelt. Aus Bremen ist zum Beispiel das Columbus-Labor, das ein Bestandteil der ISS ist, gekommen. Bei Airbus Defense and Space werden wichtige Teile der Ariane-Trägerrakete gebaut und OHB ist für die Produktion der Galileo-Satelliten verantwortlich. Und Bremen liegt strategisch günstig im Zentrum Europas mit einer hervorragenden Verkehrsanbindung.
Interessenten können sich für einen kostenfreien Messeausweis registrieren lassen:
 http://www.spacetechexpo.eu/
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Der Luft- und Raumfahrtkonzern OHB SE in Bremen
Quelle: ESA

Tags: Raumfahrt 

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Samstag, 14. November 2015 - 16:31 Uhr

Astronomie - Warum Mondgestein weniger flüchtige Stoffe enthalten als die der Erde

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Earth captured volatile-rich materials in final steps of moon's formation

This artist's concept shows a giant impact similar to the one 4.5 billion years ago that scientists think created the Earth-Moon system. Southwest Research Institute scientists combined dynamical, thermal, and chemical models of the Moon's formation to explain the relative lack of volatile elements in lunar rocks, when compared to those of Earth.
Credit: Image Courtesy of NASA/JPL-Caltech
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Scientists at Southwest Research Institute combined dynamical, thermal, and chemical models of the Moon's formation to explain the relative lack of volatile elements in lunar rocks. Lunar rocks closely resemble Earth rocks in many respects, but Moon rocks are more depleted in volatile elements like potassium, sodium, and zinc, which tend to have lower boiling points and vaporize readily.
"Explaining the Moon's volatile depletion has been a long-standing mystery, and yet it is a key piece of evidence about how the Earth-Moon system formed," said Dr. Robin Canup, associate vice president in SwRI's Space Science and Engineering Division and lead author of the Nature Geoscience paper detailing the findings.
Scientists think the Moon formed from an Earth-orbiting disk of vapor and molten matter produced by a giant impact between Earth and another Mars-sized body approximately 4.5 billion years ago. Previously, scientists had considered that volatiles vaporized by the impact might have escaped before the Moon formed.
"However, few volatiles may have actually been lost because the velocity needed to escape the Earth's gravity is quite high," said Canup. "The new research suggests instead that as the Moon completed its growth, volatile-rich melt was preferentially deposited onto the Earth, rather than onto the growing Moon."
Canup's team -- which included researchers from SwRI, Dordt College, and Washington University -- began with an existing computer simulation of the Moon's accumulation from the disk. This was combined with models for how the temperature and chemical composition of the disk material evolve with time.
The models show that the Moon acquires about the final half of its mass from melt condensed in the inner portions of the disk, close to the Earth and just inside the Moon's initial orbit. Over time, the Moon's orbit expands due to dynamical interactions with inner disk material. When the Moon is distant enough, it can no longer efficiently accumulate inner disk melt, which is instead scattered inward and assimilated by the Earth.
"We find that the inner disk melt remains hot and volatile-poor as it accretes onto the Moon. Eventually the disk cools and volatiles condense. But by the time this occurs the Moon's accumulation from this inner disk region has essentially terminated," said Canup. "So the final materials the Moon accumulates are lacking in volatile elements, even in the absence of escape."
The authors suggest that the materials the Moon initially accumulates from the outer disk could be volatile-rich, followed by a final 100- to 500-kilometer layer of volatile-poor material. In that case, the Moon's volatile content could then increase with depth, depending on the extent of mixing in the Moon's interior.
Quelle: SD

Tags: Astronomie 

1631 Views

Samstag, 14. November 2015 - 16:16 Uhr

Astronomie - Ein Polarwirbel der Venus in Farbe

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Image courtesy ESA/VIRTIS-Venus Express/INAF-IAPS/LESIA-Obs. Paris/G. Piccioni.

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On 9 November 2005, 10 years ago today, ESA's Venus Express spacecraft left Earth and began its 153-day journey to Venus. The craft then spent eight years studying the planet in detail before the mission came to an end in December 2014. One of the mission aims was to observe the planet's atmosphere continuously over long periods in a bid to understand its dynamic behaviour.
The atmosphere is the densest of all the terrestrial planets, and is composed almost entirely of carbon dioxide. The planet is also wrapped in a thick layer of cloud made mostly of sulphuric acid. This combination of greenhouse gas and perennial cloud layer led to an enormous greenhouse warming, leaving Venus' surface extremely hot - just over 450+ C - and hidden from our eyes.
Although winds on the planet's surface move very slowly, at a few kilometres per hour, the atmospheric density at this altitude is so great that they exert greater force than much faster winds would on Earth.
Winds at the 65 km-high cloud-tops, however, are a different story altogether. The higher-altitude winds whizz around at up to 400 km/h, some 60 times faster than the rotation of the planet itself. This causes some especially dynamic and fast-moving effects in the planet's upper atmosphere, one of the most prominent being its 'polar vortices'.
The polar vortices arise because there is more sunlight at lower latitudes. As gas at low latitudes heats it rises, and moves towards the poles, where cooler air sinks. The air converging on the pole accelerates sideways and spirals downwards, like water swirling around a plug hole.
In the centre of the polar vortex, sinking air pushes the clouds lower down by several kilometres, to altitudes where the atmospheric temperature is higher. The central 'eye of the vortex' can therefore be clearly seen by mapping thermal-infrared light, which shows the cloud-top temperature: the clouds at the core of the vortex are at a higher temperature, indicated by yellow tones, than the surrounding region, and therefore stand out clearly in these images.
Venus Express has shown that the polar vortices of Venus are among the most variable in the Solar System. This series of images of Venus' south pole was taken with the VIRTIS instrument from February 2007 (top left) to April 2008 (bottom right).
The shape of this vortex core, which typically measures 2000-3000 km across, changes dramatically as it is buffeted by turbulent winds. It can resemble an 'S', a figure-of-eight, a spiral, an eye, and more, quickly morphing from one day to the next.
Each of the images in this frame is roughly 4000 km across.
Quelle: SD

Tags: Astronomie 

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