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Sonntag, 9. Juni 2013 - 15:50 Uhr

Astronomie - NOAO: NGC 6334 - Eine Mini-Sternexplosion-Region?

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In this false-color image of NGC 6334, red represents the Herschel 70 micron IR image, green represents the IRAC 8 micron image and blue represents the NEWFIRM 1 micron J band. The region is about 70 light years wide. Image credit: S. Willis (CfA+ISU); ESA/Herschel; NASA/JPL-Caltech/ Spitzer; CTIO/NOAO/AURA/NSF.

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NOAO: NGC 6334 - A Mini Starburst Region?

Stars are known to form in dense clouds of gas and dust, but why do some regions show prodigious rates of star formation, while others barely produce any young stars at all? Many of the richest sites are found in distant galaxies: the name “starburst” is applied to them. Now, a team has identified a region in our own galaxy that may deserve this title, and help explain what leads to the furious production of new stars in a starburst region.

This region, NGC 6334 or informally named the Cat’s Paw Nebula, is rich in gas and dust. Long known to contain very massive young stars, NGC 6334 lies in the constellation Scorpius, toward the galactic center at a distance of about 5,500 light years, and practically in the plane of the Milky Way. It is the massive, hottest stars, classified by astronomers as type O, that cause the gas surrounding them to glow in the optical spectrum.

Imaging done at the NOAO Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, Chile, combined with data from the Spitzer Space Telescope, have enabled the team, led by Sarah Willis (Iowa State University), to catalog much fainter young stars in NGC 6334 than has been done before. Figure 1 shows combined images from space and ground-based telescopes. In this false color composite, blue is assigned to a ground-based image, green to a longer-wavelength image from †he Spitzer Space Telescope, and red to an even longer-wavelength image from the Herschel Space Telescope. The ground-based data were taken with the NOAO Extremely Wide-Field Infrared Imager, or NEWFIRM. (Figure 2).

“The study of NGC 6334 is a major component of Sarah Willis’ PhD thesis which is aimed to bridge the gap between the distant starburst galaxies and their relatively modest counterparts in our own galaxy.” says Massimo Marengo (Iowa State) who is Willis’ thesis advisor.

Starting from the brightest and most massive stars in the region, the team has identified and catalogued all the stars down to those with the brightness of the sun - approximately a million times fainter. Then, based on previous knowledge of the number of stars that form as a function of stellar mass, they can extrapolate to identify how many lower mass stars exist in the region. This is analogous to saying that if we observe the adult population in a town, we can estimate how many children live in the town, even if we can’t see them. In this way, the team can derive an estimate of the total number of stars in the region, and the efficiency with which stars are forming.

As team member Lori Allen (NOAO) says, “The observations acquired with NEWFIRM allowed us to identify and separate out the large number of contaminating sources, including background galaxies and cool stellar giants in the Galactic plane to obtain a more complete census of the newly-formed stars”. The team finds that the star formation rate in this region is equivalent to 3600 solar masses of gas becoming stars every million years – a tremendous rate even by astronomical standards.

National Optical Astronomy Observatory (NOAO) is operated by the Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation.

Quelle:NOAO/AURA/NSF


Tags: NGC 6334 

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Samstag, 8. Juni 2013 - 23:00 Uhr

Raumfahrt - Astronautin Valentina Tereshkova für ONE-WAY-TICKET TO MARS

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Record-breaker: Valentina Tereshkova made history when she completed her mission at the age of 26 (left). She has said that she would like to travel to Mars

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First woman to go into space offers to set out on one-way trip to Mars at the age of 76

  • Valentina Tereshkova became a feminist icon after solo space flight in 1963
  • Said Mars is her favourite planet and she is 'ready' to go there
  • Was involved in group who researched the possibility of travel to the planet
  • NASA aims to send a crew to orbit the red planet by the mid-2030s

A limitless imagination is key to pioneering new forms of space travel. But even by astronomical standards, it would be quite the flight of fancy.

The first woman to go to space has said she would fly to Mars, given the opportunity - even if it meant she never returned to earth.

76-year-old Valentina Tereshkova said Mars is her favourite planet and she harbours dreams of going there.

The Russian astronaut said: 'We know the human limits. And for us this remains a dream. Most likely the first flight will be one way. But I am ready'.

Ms Tereshkova, who became a national heroine at the age of 26 when she made a solo space flight, said she had been part of the group who studied the possibility of going to the Red Planet.The former textile worker completed her groundbreaking space mission in 1963 in the spaceship Vostok VI.

Ms Tereshkova was an amateur parachutist when she was recruited into a cosmonaut programme in Moscow.

She was trained with three other women as part of Kruschev's project for the first woman in space to be from the Soviet Union.

But she was the only woman to complete the mission. She was honored with the title Hero of the Soviet Union.

During her three-day mission, she circled the Earth 48 times and set a new record for time in space by completing the most orbits in the shortest recorded time.

Her flight was a major propaganda coup for the Soviet Union.

She was later given the United Nations Gold Medal of Peace in her role as a spokesperson for the Soviet Union.


One giant leap for womankind: Tereshkova made headlines in 1963
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On June 16, Russia will celebrate the 50th anniversary of Tereshkova's historic flight.

Astronauts traveling to and from Mars would be bombarded with as much cosmic radiation as they would get from a full-body CT scan about once a week for a year, researchers predict.

That dose is enough to raise their cancer risk by about three per cent, but experts caution that there are many uncertainties about the space environment's effects on the body.

The U.S. space agency, Nasa, aims to send a crew to orbit the red planet by the mid-2030s.

Private outfits like Inspiration Mars - backed by Nasa engineer-turned-space tourist Dennis Tito - are seeking volunteers for a Mars flight.

Quelle: Mail Online












Tags: Valentina Tereshkova 

3204 Views

Samstag, 8. Juni 2013 - 14:40 Uhr

Raumfahrt - SMOS zeichnete vor dem Hochwasser Rekordwerte bei der Bodenfeuchte auf!

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Deutschland und Teile Zentraleuropas kämpfen mit den schlimmsten Überschwemmungen seit Jahrhunderten. Obwohl diese tragischen Ereignisse viele Ursachen haben, könnten die Daten des ESA-Satelliten SMOS helfen, die Hochwasservorhersage in der Zukunft zu verbessern.

Wie der Name schon sagt, liefert die Soil Moisture and Ocean Salinity (SMOS) Mission Daten über die Bodenfeuchte an der Erdoberfläche und über den Salzgehalt des Meeresoberflächenwassers.

Das massive Hochwasser, mit dem Mitteleuropa derzeit zu kämpfen hat, verdanken wir einem nassen Frühjahr und plötzlich auftretenden schweren Regenfällen.

Wissenschaftler nutzen die Informationen von SMOS, um zu verstehen, wie der Wasserkreislauf zwischen den Ozeanen, der Atmosphäre und dem Festland funktioniert. Die Daten tragen auch zur Verbesserung der Wetterberichte bei.

SMOS ist mit einem neuartigen Mikrowellensensor ausgestattet, mit dem Bilder der Strahlungstemperatur erstellt werden können, um Informationen über die Bodenfeuchte zu erhalten.

Vor den sintflutartigen Regenfällen zeigten Daten der SMOS-Mission, dass die Böden in Deutschland eine extrem hohe Feuchtigkeit aufwiesen. Werte in der gemessenen Höhe waren bislang noch nie beobachtet worden.

Die SMOS-Daten können dazu genutzt werden, die Sättigung des Bodens zu überwachen“, erklärt Matthias Drusch, ESA-Missionswissenschaftler für SMOS.
Ende Mai haben wir gesehen, dass der Boden fast vollständig gesättigt war und die Bodenfeuchte einen Rekordwert erreichte. Da das überschüssige Wasser nicht mehr im Boden versickern konnte, bedeutete mehr Regen, dass dieser sofort ablief. So ist dieses furchtbare Hochwasser entstanden.
Numerische Wettervorhersagezentren bewerten derzeit die Möglichkeit, SMOS-Daten zur Verbesserung von Wetter- und Hochwasservorhersagen zu nutzen, so dass wir in der Zukunft hoffentlich besser aufgestellt sein werden, um solche Ereignisse genauer vorhersagen zu können.“

Satellitenmissionen wie RapidEye und die DLR-Mission TerraSAR-X unterstützen mit Bildern die Hilfsmaßnahmen auf Basis der Internationalen Charta für Weltraum- und Naturkatastrophe

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Quelle: ESA


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Samstag, 8. Juni 2013 - 11:03 Uhr

Raumfahrt - Start von Sojus-2,1B mit Aufklärungs-Satelliten

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A Soyuz-2.1B carrier rocket orbited a military satellite on Friday, the defense ministry’s spokesman in charge of Russia's Aerospace Defense Forces said.

The rocket blasted off from the Plesetsk launch site in Russia’s north at 22:37 Moscow time on Friday.

"The spacecraft separated from the third stage of the rocket as scheduled,” Col. Dmitry Zenin said.

According to previous reports, the satellite is the second in the new Persona series of electro-optical reconnaissance satellites based on the Resurs DK remote sensing satellite.

The first Persona satellite (Kosmos 2441) was launched onto a sun synchronous orbit in July 2008 but reportedly malfunctioned in February 2009 due to a failure in electronic components.

Russia operates a network of about 60-70 military reconnaissance satellites, featuring updated imaging technology and an extended lifetime of up to seven years, according to open sources.

Quelle: RIANOVOSTI


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Samstag, 8. Juni 2013 - 10:47 Uhr

Mars-Chroniken - Rover Opportunity findet Spuren von "Trinkwasser"

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This panorama from NASA's Opportunity rover, made on June 1, shows Solander Point rising up on the Martian horizon. Mission managers plan to get the solar-powered rover to a north-facing slope on Solander Point by August, so that it can shelter there during the Martian winter.

Opportunity rover finds traces left by 'water you can drink' on ancient Mars

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Nearly 10 years after its launch, NASA's Opportunity rover has found its first evidence that Mars once had non-acidic water — the kind of water that could easily sustain the life we typically see on Earth.

"This is water that you can drink," Cornell astronomer Steve Squyres, principal investigator for Opportunity's long-lived Mars mission, told reporters Friday.

The water isn't there anymore, but the minerals left behind bear an aluminum-rich chemical signature that suggests they were formed through interaction with neutral-pH water. That's different from the previous evidence that Opportunity found, pointing to more acidic water. Some extreme forms of life on Earth could tolerate that environment, but it wouldn't have been as friendly an environment for prebiotic chemistry — the chemistry that's thought to have given rise to life on Earth.

The newly announced findings, based on X-ray analysis of a rock nicknamed Esperance, add to similar evidence of neutral water that was found on the other side of the Red Planet by NASA's bigger and more capable Curiosity rover. Taken together, they flesh out the story of a planet that was friendly to life's conditions early in its existence but became colder, drier and less hospitable as it lost its global magnetic field and much of its atmosphere.

How Mars lost its mojo
The mission's deputy principal investigator, Ray Arvidsen of Washington University at St. Louis, sketched out a scenario in which Mars had a more Earthlike climate in the planet's early years. But as the planet wound down, the rains stopped, the oceans dried up, and more of the water that was available on Mars percolated up from the subsurface. That water picked up iron, sulfur and other elements, resulting in a more acidic pH.

The differences in the mineral signatures seen by Opportunity in older and newer rocks probably reflect "the transition from the early wet Mars to the cold dry Mars," Arvidsen said.

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NASA's Opportunity rover analyzed the composition of a rock called Esperance, highlighted in this Feb. 23 image, and scientists determined that the minerals found there were probably formed through interaction with neutral-pH water. That's in contrast to previous evidence from Opportunity pointing to acidic water on ancient Mars.

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Arvidsen and Squyres were reluctant to talk about time frames for that transition, but Squyres speculated that the minerals seen in the Esperance rock were formed during the first billion years of Mars' 4.6 billion-year existence. He said the rock appeared to be older than the 14-mile-wide (22-kilometer-wide) crater where it was found, known as Endeavour Crater. 

Opportunity, which was launched from Cape Canaveral in July 2003 and landed on Mars in January 2004, has been at Endeavour Crater for almost two years. Squyres marveled at the fact that the rover found the evidence for neutral water so soon after Curiosity found the same thing.

"It's really striking to me how similar are the stories that are being told by the rocks that were recently investigated by Opportunity at Endeavour Crater, and the rocks that were recently investigated by Curiosity at Gale Crater," Squyres said. He said that the decisions on site selection "paid off on both sides of the planet, almost simultaneously."

Squyres ranked the find at Esperance among the nearly 10-year-long mission's top four or five discoveries.

Opportunity's next stop
Now Opportunity is heading for a new destination on the crater's rim: a rise called Solander Point, where the rover is due to spend the Martian winter. The rover team wants to position Opportunity on a north-facing, 15-degree slope, which will make it easier for its solar arrays to soak up power. While it's at Solander Point, Opportunity will study a rich range of geological layers that could provide further insights into the Red Planet's history.

"We consider it Sol 1 all over again for Opportunity," said John Callas, the Opportunity mission's project manager at NASA's Jet Propulsion Laboratory. "Sols" are Martian days: Opportunity is currently on Sol 3331 of what was originally expected to be a 90-sol mission on Mars.

Callas said the rover is still working fine, except for some "arthritis" in its mechanical joints and a potentially worrisome computer issue he called "flash memory amnesia." The temporary memory loss was last experienced about two weeks ago.

 
 
"Right now it's only an occasional annoyance," Callas said.
This mosaic of images from NASA's Mars Reconnaissance Orbiter traces the route taken by the Opportunity rover since its landing in 2004. The rover is currently at Cape York and is due to head for a spot called Solander Point, at the northern tip of Cape Tribulation on the rim of Endeavour Crater. Solander Point is more than 1.2 miles (2 kilometers) away, but mission managers expect the rover to complete the trip by August, around the time of Mars' southern autumnal equinox.
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The Mars rover mission, which launched Opportunity as well as a second rover named Spirit toward the Red Planet in 2003, was originally budgeted at $800 million. Spirit lost its mobility and fell silent in 2010, but NASA is still funding Opportunity on maintenance mode to the tune of $14 million a year, Callas said.

Callas said he never expected the rover to last this long.

"This is like your car not lasting 200,000 miles, or even a million miles. You're talking about a car that lasts 2 million miles without an oil change," he said. "At this point, how long Opportunity lasts is anyone's guess."

Correction for 11:44 p.m. ET: I originally wrote that the Mars rovers' primary mission was supposed to last 30 sols, but it was actually 90 sols. Thanks for setting me straight, ToSeek!

Quelle: NBC


Tags: Rover Opportunity 

3196 Views

Freitag, 7. Juni 2013 - 12:27 Uhr

Raumfahrt - Sierra Nevada Corporation beginnt mit Dream Chaser-Hybrid Raketen-Antriebs-Test

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Hybrid Motor Test on June 4,2013.                  Photo Credit: Sierra Nevada Corporation

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Sierra Nevada Corporation (SNC) announces the successful start of the latest phase of hybrid rocket motor qualification testing for the Dream Chaser® flight vehicle.  SNC completed two tests this week at its rocket test facility in San Diego, Calif. A motor firing and ignition test was completed in preparation for upcoming motor tests under the current Commercial Crew Integrated Capability (CCiCap) award. SNC will conduct another series of hybrid motor firings to meet the next CCiCap contracted milestone beginning this summer.
After required modifications were completed, the test firing was conducted in order to validate Dream Chaser’s motor test stand.  This was after required modifications were completed and to ensure that SNC can move forward with the future heavy weight motor test series with minimal test stand risk. The Dream Chaser version of the hybrid rocket motor was last tested in 2010 under the Commercial Crew Development Program (CCDev1) Space Act Agreement during which SNC completed three successful test firings of a single hybrid motor in one day.
In addition to manufacturing these motors for Dream Chaser, SNC also manufactures the hybrid motors for Virgin Galactic’s SpaceShipTwo vehicle which has undergone test firings on dozens of hybrid motors over the last two years.  As announced in the SNC news release (April 29, 2013), SpaceShipTwo successfully completed its first powered flight test using SNC’s hybrid motor to power the vehicle to an altitude of 55,000 feet and reaching Mach 1.2.
“We are eager to begin the next series of motor testing for Dream Chaser,” said Mark Sirangelo corporate vice president and head of SNC’s Space Systems. “With the successful qualification this week in San Diego and the success of the powered flight of SpaceShipTwo, we are even more confident that our hybrid motor technology is the safest and most reliable system for human transportation.”
SNC’s hybrid rocket systems offer a safe, high performing, and non-toxic alternative to solid and hydrazine liquid propulsion systems.  As the rocket motor fuel is industrial rubber, there are no special handling or transportation requirements, which greatly reduces the lifecycle cost to customers.
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Quelle: SNC

Tags: Dream Chaser 

3192 Views

Freitag, 7. Juni 2013 - 09:14 Uhr

Astronomie - ALMA entdeckt eine Kometenfabrik

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Neue Beobachtungen einer „Staubfalle” um einen jungen Stern lösen langjähriges Rätsel um die Entstehung von Planeten
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Ein Astronomenteam mit Beteiligung des Max-Planck-Instituts für Extraterrestrische Physik in Garching und des Instituts für Theoretische Astrophysik am Zentrum für Astronomie der Universität Heidelberg hat mit dem Atacama Large Millimeter/submillimeter Array (ALMA) eine Region um einen jungen Stern aufgenommen, in der Staubpartikel langsam anwachsen können, indem sie zusammenklumpen. Damit konnte eine solche Staubfalle erstmals eindeutig beobachtet und modelliert werden. Das lange Jahre ungeklärte Rätsel wie Staubteilchen in den Scheiben um junge Sterne zu größeren Objekten anwachsen können, aus denen schließlich Kometen, Planeten und andere Körper aus Gestein werden, konnte damit nun gelöst werden. Die Ergebnisse erscheinen am 7. Juni 2013 in der Fachzeitschrift Science.
Zwar wissen Astronomen mittlerweile, dass es Unmengen von Planeten um andere Sterne gibt, man versteht aber noch nicht vollständig, wie sie eigentlich entstehen. Auch viele Aspekte bei der Bildung von Kometen und anderen gesteinsartigen Objekten waren bislang ein Rätsel. Neue Beobachtungen, die die Leistungsfähigkeit von ALMA ausnutzen, können nun eine der wichtigsten dahingehenden Fragen beantworten: Wie schaffen es winzige Staubkörnchen in den Scheiben um junge Sterne immer größer zu werden – und schließlich zu Steinen oder sogar Felsbrocken von über einem Meter Durchmesser anzuwachsen?
Computermodelle lassen vermuten, dass Staubkörner wachsen, wenn sie zusammenstoßen und aneinander kleben bleiben. Wenn jedoch größere Staubkörner bei hohen Geschwindigkeiten miteinander kollidieren, werden sie oft wieder in kleine Stückchen zerschlagen und fangen somit wieder bei Null an. Aber selbst wenn das nicht passiert, zeigen Modelle, dass sich die größeren Staubkörner aufgrund der Reibung zwischen Staub und Gas in der Scheibe, in der sie sich befinden, schnell zu deren Zentrum bewegen und schließlich auf ihren Mutterstern fallen würden, so dass sie ebenfalls keine Chance hätten größer zu werden.
Der Staub braucht also eine Art sicheren Hafen, in dem Staubteilchen weiter wachsen können, bis sie groß genug sind, um weiter bestehen zu können [1]. Solche „Staubfallen” wurden zwar schon zuvor als Lösung vorgeschlagen, aber bislang gab es keine Beobachtungen, die ihre Existenz belegt haben.
Nienke van des Marel, eine Doktorandin an der Sternwarte in Leiden in den Niederlanden und Erstautorin des Fachartikels, in dem die neuen Ergebnisse präsentiert werden, hat zusammen mit anderen Astronomen mit ALMA die Scheibe in einem Sternsystem namens Oph-IRS 48 [2] untersucht. Das Team fand heraus, dass der Stern von einem Ring aus Gas mit einem Loch umgeben war, das vermutlich von einem unsichtbaren Planeten oder einem Begleitstern verursacht worden war. Frühere Beobachtungen mit dem Very Large Telescope der ESO hatten bereits gezeigt, dass kleine Staubteilchen dort eine ähnliche Ringstruktur bilden. Doch die neuen ALMA-Aufnahmen von dem Ort, an dem die millimetergroßen Staubteilchen gefunden wurden, sah vollkommen anders aus.
„Wir waren wir von der Verteilung des Staubs auf dem Bild vollkommen überrascht”, erzählt van der Marel. „Anstatt des Rings, den wir erwartet hatten, sieht man die Form einer Cashewnuss! Wir mussten uns erstmal selbst davon überzeugen, dass diese Struktur auch wirklich echt ist. Das starke Signal und die Schärfe der ALMA-Aufnahmen lassen daran aber keinen Zweifel. Erst danach haben wir begriffen, was wir da entdeckt hatten.”
Bei dem Fund handelt es sich um eine Region, in der größere Staubkörner gefangen werden und durch Kollisionen und Aneinanderhaftenbleiben weiter wachsen können. Es handelt sich um eine Staubfalle – genau das, wonach die Theoretiker gesucht hatten.
„Es ist sehr wahrscheinlich, dass wir auf eine Art Kometenfabrik schauen, da die Bedingungen dort im Moment gerade so sind, dass Staubteilchen von Millimeter- zu Kometengröße heranwachsen können. Es ist unwahrscheinlich, dass sich aus dem Staub bei dieser Entfernung vom Stern ausgewachsene Planeten bilden. Aber ALMA wird in naher Zukunft auch in der Lage sein, Staubfallen näher am Mutterstern zu beobachten, wo derselbe Mechanismus am Werk ist. Solche Staubfallen wären dann wirklich die Geburtsstätten von neuen Planeten”, erklärt van der Marel.
Eine Staubfalle entsteht, wenn größere Staubteilchen in Gebiete höheren Drucks wandern. Computermodelle haben gezeigt, dass solch ein Hochdruckgebiet durch die Bewegung des Gases am Rand einer Lücke entstehen kann – ähnlich wie jenes, das in der Scheibe beobachtet wird.
„Die Kombination aus Modellierung und hochqualitativen ALMA-Beobachtungen macht dieses Projekt einzigartig”, erläutert Cornelis Dullemond vom Institut für Theoretische Astrophysik am Zentrum für Astronomie der Universität Heidelberg, Mitglied des Teams und ein Experte auf dem Gebiet der Staubentwicklung und der Scheibenmodellierung. „Etwa zur gleichen Zeit als diese Beobachtungen gemacht wurden, haben wir an Modellen gearbeitet, die genau diese Art von Strukturen vorhergesagt hat: ein sehr glücklicher Zufall also.”
Die Beobachtungen wurden durchgeführt, als ALMA sich noch im Aufbau befand. Das Team hat dazu den Band 9-Empfänger von ALMA genutzt [3] – in Europa hergestellte Geräte, die es ALMA ermöglichen seine bisher schärfsten Bilder zu erstellen.
„Diese Beobachtungen demonstrieren, dass ALMA selbst mit weniger als der Hälfte des vollen Ausbaus in der Lage ist, herausragende wissenschaftliche Arbeit zu leisten”, ergänzt Ewine van Dishoeck von der Sternwarte Leiden, die bereits 20 Jahre lang maßgebliche Beiträge zum ALMA-Projekt leistet. „Der unglaubliche Sprung in Band 9, sowohl in der Empfindlichkeit als auch bei der Schärfe der Bilder, gibt uns die Möglichkeit die grundlegenden Aspekte der Planetenentstehung auf eine Art und Weise zu untersuchen, die uns bislang verschlossen gewesen ist”
Endnoten
[1] Die Ursache für die Staubfalle, in diesem Fall ein Wirbel im Gas der Scheibe, hat eine typische Lebensdauer von mehreren Hunderttausend Jahren. Aber auch dann wenn die Staubfalle nicht mehr funktioniert, würde es merhere Millionen Jahre dauern, bis der angesammelte Staub sich wieder verteilen würde, was den Staubkörnern ausreichend Zeit verschafft, um zu wachsen.
[2] Der Name setzt sich aus dem Namen des Sternbilds, in dem das System in einer Sternentstehungsregiongefunden wurde, und der Art der Quelle zusammen. Dabei steht Oph für das Sternbild Ophiuchus (der Schlangenträger) und IRS für Infrarotquelle. Der Abstand von Oph-IRS 48 zur Erde beträgt etwa 400 Lichtjahre.
[3] ALMA kann Beobachtungen in verschiedenen Frequenzbändern durchführen. Band 9, das einem Wellenlängenbereich von etwa 0,4-0,5 Millimetern entspricht, ist der Modus, der bislang die schärfsten Aufnahmen liefert.  
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Diese Aufnahme vom Atacama Large Millimeter/submillimeter Array (ALMA) zeigt die Staubfalle im System Oph-IRS 48. Die deutliche Asymmetrie in der Emission des Staubes zwischen nördlichem und südlichem Teil der Scheibe (um mindestens ein Faktor 130) weist auf die Existenz der Staubfalle hin. Sie ist eine Art sicherer Hafen für die kleinen Steinchen in der Scheibe, wo sie so lange zusammenklumpen und wachsen können, bis sie groß genug sind, um alleine weiter bestehen zu können.
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Diese Aufnahme vom Atacama Large Millimeter/submillimeter Array (ALMA) zeigt die Staubfalle im System Oph-IRS 48. Die Staubfalle ist eine Art sicherer Hafen für die kleinen Steinchen in der Scheibe, wo sie so lange zusammenklumpen und wachsen können, bis sie groß genug sind, um alleine weiter bestehen zu können.
Die grüne Region zeigt, wo sich die größeren (millimetergroßen) Partikel befinden und stellt die Staubfalle dar, die von ALMA entdeckt wurde. Der orangene Ring zeigt, wo mit dem VISIR-Instrument am Very Large Telescope der ESO viel feinere (mikrometergroße) Staubteilchen beobachtet wurden. 
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Diese beschriftete Aufnahme vom Atacama Large Millimeter/submillimeter Array (ALMA) zeigt die Staubfalle im System Oph-IRS 48. Die Staubfalle ist eine Art sicherer Hafen für die kleinen Steinchen in der Scheibe, wo sie so lange zusammenklumpen und wachsen können, bis sie groß genug sind, um alleine weiter bestehen zu können. Die grüne Region zeigt, wo sich die größeren Partikel ansammeln. Der Durchmesser der Umlaufbahn des Neptuns ist oben links als Größenvergleich eingezeichnet.
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Quelle: ESO
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The proposed disk structure of Oph IRS 48. 
Quelle: NRAO

3177 Views

Donnerstag, 6. Juni 2013 - 21:00 Uhr

Raumfahrt - Wallops Raketen-Start

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5.06.2013

Rocket launch from Wallops to study stars, galaxies
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A rocket is scheduled to launch from NASA's Wallops Flight Facility tonight to study how the first stars and galaxies formed and how brightly their nuclear fuel burned.
The launch is expected to lift off between 11 and 11:50 p.m., carrying the Cosmic Infrared Background ExpeRiment or CIBER, according to a release from the space agency.
The CIBER has flown three times on a NASA sounding rocket from White Sands Missile Range in New Mexico.
This time, the experiment will fly on a larger and more powerful rocket and is expected to reach a higher altitude. The instruments will have longer observation time before the experiment splashes down about 400 miles off the coast. It won’t be recovered.

A rocket is scheduled to launch from NASA's Wallops Flight Facility tonight to study how the first stars and galaxies formed and how brightly their nuclear fuel burned.

The launch is expected to lift off between 11 and 11:50 p.m., carrying the Cosmic Infrared Background ExpeRiment or CIBER, according to a release from the space agency.

The CIBER has flown three times on a NASA sounding rocket from White Sands Missile Range in New Mexico.

This time, the experiment will fly on a larger and more powerful rocket and is expected to reach a higher altitude. The instruments will have longer observation time before the experiment splashes down about 400 miles off the coast. It won’t be recovered.

LIVE-Frams: NASA

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When did the first stars and galaxies form in the universe? How brightly did they burn their nuclear fuel?

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Numerical simulation of the density of matter when the universe was one billion years old. Galaxies formation follows the gravitational wells produced by dark matter, where hydrogen gas coalesces, and the first stars ignite. CIBER studies the total sky brightness, to probe the component from first stars and galaxies using spectral signatures, and searches for the distinctive spatial pattern seen in this image, produced by large-scale structures from dark matter. Photo: Courtesy of Jamie Bock/Caltech

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Scientists will seek to gain answers to these questions with the launch of the Cosmic Infrared Background ExpeRIment (CIBER) on a Black Brant XII suborbital sounding rocket between 11 and 11:59 p.m. EDT, June 4 from the Wallops Flight Facility in Virginia.
Jamie Bock, CIBER principal investigator from the California Institute of Technology, said, “The first massive stars to form in the universe produced copious ultraviolet light that ionized gas from neutral hydrogen. CIBER observes in the near infrared, as the expansion of the universe stretched the original short ultraviolet wavelengths to long near-infrared wavelengths today. CIBER investigates two telltale signatures of first star formation -- the total brightness of the sky after subtracting all foregrounds, and a distinctive pattern of spatial variations.”
“The objectives of the experiment are of fundamental importance for astrophysics, to probe the process of first galaxy formation, but the measurement is also extremely difficult technically,” he noted.
This will be the fourth flight for CIBER on a NASA sounding rocket. The previous launches were in 2009, 2010, and 2012 from the White Sands Missile Range, New Mexico. After each flight the experiment or payload was recovered for post-calibrations and re-flight.
For this flight CIBER will fly on a larger and more powerful rocket than before. This will loft CIBER to a higher altitude than those previously obtained, thus providing longer observation time for the instruments. The experiment, which will safely splash down in the Atlantic Ocean more than 400 miles off the Virginia coast, will not be recovered.
CIBER previously flew on two-stage Black Brant IX sounding rockets. Bock said, “The collection of data from the three flights allows us to compare data and rigorously test sources of potential systematic error from both the instrument and astrophysical foregrounds. We have been through the end-to-end process in analyzing our data, so we understand the benefits of going with a non-recovered Black Brant XII. We also know the performance of the instrument very well from these flights and that makes us confident going forward with this more capable but final flight.”
The 70-foot tall four-stage Black Brant XII rocket will carry CIBER to an altitude of about 350 miles. According to Bock, “This flight is pioneering a new direction in the astrophysics program in that we are flying our instrument on a non-recovered Black Brant XII. The XII gives us a significantly higher trajectory, providing about 560 seconds of flight time above 250 km (155 miles) altitude, compared with 250 seconds on standard Black Brant IX flights out of White Sands.” 
“Our experience in the near-infrared waveband is that we see appreciable emission from the atmosphere up to 250 km. The higher trajectory allows us to do some new things that are not possible on a Black Brant IX. For example, we expect to have enough independent images of the sky to directly determine the in-flight gain of the infrared cameras, which will allow us to measure background fluctuations in single exposures. This gives us a much more direct way to compare with satellite data than the statistical combinations we have had to use to date. The higher trajectory of course comes with a price in that the payload is not recovered,” he said.
CIBER is a cooperative instrument designed and built by the California Institute of Technology, University of California Irvine, the Japan Aerospace Exploration Agency (JAXA), and the Korean Astronomy and Space Science Institute (KASI). The same team is also developing an improved follow-on experiment, with more capable optics and detector arrays, that will be completed next year.
Backup launch days for this project are June 5 – 10.
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Update: 6.06.2013
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WALLOPS ISLAND
Despite being scrubbed Tuesday because of problems with instrument cooling, a rocket was successfully launched from NASA's Wallops Flight Facility tonight.
The launch was scrubbed Tuesday because of insufficient time to cool the instruments on the payload down to the required temperatures before launch, a news release said.
The Cosmic Infrared Background ExpeRiment or CIBER has flown three times on a NASA sounding rocket from White Sands Missile Range in New Mexico.
This time, the experiment will fly on a larger and more powerful rocket and is expected to reach a higher altitude. The instruments will have longer observation time before the experiment splashes down about 400 miles off the coast. It won’t be recovered.
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Rocket Launches from Wallops Flight Facility
A NASA Black Brant XII suborbital rocket streaks into the night sky following its launch at 11:05 p.m. EDT on June 5, 2013 from the Wallops Flight Facility in Virginia. The rocket carried the Cosmic Infrared Background ExpeRiment (CIBER) to an altitude of approximately 358 miles above the Atlantic Ocean by the four-stage rocket. The launch, seen here with multiple stages firing off, was reportedly seen from as far away as central New Jersey, southeastern Pennsylvania and northeastern North Carolina. With CIBER, scientists are studying when the first stars and galaxies formed in the universe and how brightly they burned their nuclear fuel.
Image Credit: NASA/Jamie Adkins

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Donnerstag, 6. Juni 2013 - 20:00 Uhr

Luftfahrt - Private UFO-Drohne am Himmel

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Einen Kindheitstraum hat sich Alexander Kraus aus Bergtheim erfüllt. Der 59-jährige Physik-, Mathematik und Religionslehrer an der Jakob-Stoll-Realschule in Würzburg hat ein Ufo gebaut. Der „Oktokopter“ hat 1,20 Meter Durchmesser, ist aus bemaltem Bau-Styropor und wird von acht Propellern elektrisch in die Luft gehoben. Der Jungfernflug hat jedenfalls geklappt
„Mein Oktokopter ist mit Elektronik vom Feinsten ausgestattet, so wie sie auch in unbemannten Drohnen zum Einsatz kommt“, erläutert der stolze Erfinder. Über Funk wird „das Ufo“ ferngesteuert und weil es rot und blau bemalt ist und rundum blinkt und glitzert, ist es beinahe eine unheimliche Erscheinung am Himmel. Zu Vorführungszwecken lässt der Tüftler die Scheibe nur ein paar Meter vom Boden abheben. Aber wenn er wollte, könnte sein Ufo „bis außer Sichtweite“ davonfliegen.
„Schon mein Vater schwärmte von fliegenden Untertassen. Er hat uns Kindern diesen Floh ins Ohr gesetzt“, erläutert Kraus seine Motivation. Als Gymnasiast in Gelnhausen habe er einen Hubschrauber entwickelt und damit als 17-jähriger bei „Jugend forscht“ mitgemacht. Als Physikstudent in München bastelte er sein erstes Oktokoptermodell aus Styropor mit Elektromotoren. Aber damals waren Motoren und Akkus einfach zu schwer zum Abheben.
Erst neue Akku-Entwicklungen und die preiswert gewordenen „Flightboards“ aus der Modellbauelektronik, Fortschritte in der Sensor-Technik und beim Militär brachten ihm seinen Traum mit der „Fliegenden Untertasse“ näher. Für die stilechte „Show“ baute Kraus zudem 400 LEDs ein. Das Blinklicht und die hinteren Flugteile haben grünes Licht, vorn und an den Rotorschächten ist blaues Licht, ein Pfeil hat weiße LEDs. Auf diese Weise kann Kraus vom Boden aus die Fluglage seines Ufos beurteilen.
Rund 700 Euro Baukosten hat der Prototyp verschlungen. „Vergleichbares auf dem Markt kostet leicht 3000 Euro oder mehr“, meint Kraus. Seine Ufo-Styroporscheibe soll noch eine kleine, leistungsfähige Kamera unter einer dünnen Klarsichtkoppel bekommen. Damit will er vom Himmel aus in jede beliebige Richtung schauen können.
Erfinder Kraus könnte sich vorstellen, dass sein Ufo auf Flugschauen ein Hingucker ist. Werbeflächen stünden auf dem Oktokopter auch zur Verfügung. Die Scheibe passt in jeden Kofferraum und wiegt nur 3,4 Kilogramm.

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Donnerstag, 6. Juni 2013 - 13:55 Uhr

Mars-Chroniken - MARS-EXPRESS: Die Hochwasser von Mars

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Kasei Valles

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Dramatic flood events carved this impressive channel system on Mars covering 1.55 million square kilometres, shown here in a stunning new mosaic from ESA’s Mars Express.
The mosaic, which features the spectacular Kasei Valles, comprises 67 images taken with the spacecraft’s high-resolution stereo camera and is released during the week of the 10th anniversary of the spacecraft’s launch to the Red Planet.
Kasei Valles is one of the largest outflow channel systems on Mars – from source to sink, it extends some 3000 km and descends by 3 km in altitude. The scene covered in the mosaic spans 987 km north–south (19–36°N) and 1550 km east–west (280–310°E).
The channel originates beyond the southern edge of this image near Valles Marineris, and empties into the vast plains of Chryse Planitia to the east.
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Kasei Valles topography
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Kasei Valles splits into two main branches that hug a broad island of fractured terrain – Sacra Mensa – rising 2 km above the channels that swerve around it. While weaker materials succumbed to the erosive power of the fast-flowing water, this hardier outcrop has stood the test of time.
Slightly further downstream, the flood waters did their best to erase the 100 km-wide Sharonov crater, crumpling its southern rim. Around Sharonov, many small streamlined islands form teardrop shapes rising from the riverbed, carved as water swept around these natural obstacles.
The region between Sacra Mensa and Sharonov is seen in close-up detail in the perspective view below, looking downstream from the northern flank of Kasai Valles.
Zooming into the valley floor reveals small craters with bright dust ‘tails’ seemingly flowing in the opposite direction to the movement of water. In fact, these craters were formed by impacts that took place after the catastrophic flooding, their delicate tails created by winds blowing in a westwards direction ‘up’ valley.
Their raised rims influence wind flow over the crater such that the dust immediately ‘behind’ the crater remains undisturbed in comparison to the surrounding, exposed, plains.
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Perspective view of Kasei Valles
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Kasei Valles has likely seen floods of many different sizes, brought about by the changing tectonic and volcanic activity in the nearby Tharsis region over 3 billion years ago.
The landscape was pulled apart under the strain of these forces, groundwater bursting from its ripped seams to create not only violent floods, but also the unique fracture patterns seen at Sacra Mensa and Sacra Fossae.
Snow and ice melted by volcanic eruptions also likely contributed to torrential, muddy outpourings, while glacial activity may have further shaped the channel system.
Now silent, one can only imagine from examples on Earth the roar of gushing water that once cascaded through Kasei Valles, undermining cliff faces and engulfing craters, and eventually flooding onto the plains of Chryse Planitia.
Quelle: ESA

Tags: MARS-EXPRESS 

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