samedi 10 août 2013

Astronaut Michael Foale Leaves NASA After 26-Year Career












NASA patch.

Aug. 10, 2013

NASA astronaut Michael Foale has retired, ending a 26-year space agency career that included 375 days in space during six space shuttle missions and extended stays aboard two space stations.

Foale spent 145 days aboard the Russian space station Mir in 1997 and 194 days aboard the International Space Station as commander of Expedition 8 from October 2003 to April 2004. He also conducted four spacewalks over his NASA career totaling almost 23 hours.

NASA astronaut Michael Foale

"We salute Mike and his contributions to NASA as an accomplished member of the astronaut corps," said NASA Administrator Charles Bolden. "Starting with his first flight, shuttle mission STS-45, when we flew together in 1992, Mike has worked tirelessly to support NASA's quest to explore the unknown. I know Mike will go on to do more great things as he continues to support the aerospace industry in his new endeavor."

Foale held many positions during his NASA career, including chief of the Astronaut Office Expedition Corps, assistant director (technical) of the agency's Johnson Space Center in Houston, and deputy associate administrator for exploration operations at NASA Headquarters in Washington. He most recently worked in support of Soyuz and International Space Station operations, as well as space station spacewalk activity and spacesuit development.

Foale's future plans include advancing green aviation technology. For Foale's complete NASA biography, visit: http://go.nasa.gov/14gPLKx

For more information about NASA programs, visit: http://www.nasa.gov

Image, Text, Credit: NASA.

Greetings, Orbiter.ch

vendredi 9 août 2013

Mapping Tons of Meteoric Dust in the Sky











Asteroid Watch.

Aug. 9, 2013

On Aug.11 and 12, 2013, the annual Perseid meteor shower will peak, filling the sky with streaks of light, commonly known as shooting stars. Such visually stunning showers are actually but the tip of the iceberg when it comes to meteoroids slamming into Earth's atmosphere: Some 10 to 40 tons of material of invisible meteoric dust enters the atmosphere from interplanetary space every day.

The big showers like the Perseids, and later the Leonids in November, are caused when Earth and its atmosphere travels through a region of the sky filled with left over debris lost by a particular comet. In the case of the Perseids, the small fragments were ripped of the tail of comet Swift-Tuttle, which orbits the sun once every 130 years. The fragments light up due to the immense friction created when they plough into the gas surrounding Earth. Each such fragment is approximately the size of a dime, but the more constant, sporadic meteoroids have been around much longer, breaking down over time into tiny fragments only about as wide as a piece of human hair.

"This is interplanetary dust," said Diego Janches, who studies micrometeoroids at NASA's Goddard Space Flight Center in Greenbelt, Md. "The fragments are either remnants from the solar system's formation, or they are produced by collisions between asteroids or comets from long ago."


Image above: Larger meteoroids cause bright flashes of light when they hit Earth's atmosphere, such as this fireball caught during the Perseid meteor shower Aug. 12, 2006. The bulk of meteoric activity is much less showy: Some 10 to 40 tons of meteor dust enter our atmosphere every day. Image Credit: Courtesy of Pierre Martin.

Janches researches such tiny meteoroids using radar systems set up around the globe, in places such as Sweden, Puerto Rico and Alaska, or the radar system he deployed and operates in Tierra Del Fuego, Argentina. These fragments plough into Earth's atmosphere at speeds of between 7 to 44 miles per second. They also bring with them minerals and metals from their parent bodies, such as sodium, silicon, calcium and magnesium.

"The small meteoroids feed the atmosphere with all these extra materials," Janches said. "They come in, release metallic atoms that get deposited in the mesosphere and then get pushed around from pole to pole by the general global circulation. So by using the metals as tracers, you can answer some important questions about the general composition and movement of the atmosphere."

The radar systems set up around the world can track such motion. The meteors collide with atoms in the atmosphere and leave behind a path of electrons and charged particles. This electrically charged region acts as a perfect mirror for radar waves, so the radar bounces back carrying both position information and Doppler shift information. This can be used to measure speed and direction of the background atmospheric winds at the altitudes where the meteoric tails are produced, between 40 and 60 miles high in the sky. Because there are so many such trails, they can be used to measure the velocity and direction of the winds continuously, helping to map out very complex wind patterns on a minute-by-minute basis.

Similar techniques, but using lasers, can be used to map how something like sodium sweeps through the entire atmosphere, thus tracing the global circulation system. This system also sweeps the meteoric dust to the poles where, during the summertime, they can serve as nuclei for ice crystals in the sky forming what's called night-shining or noctilucent clouds.

Image (mentioned), Text, Credits: NASA / Goddard Space Flight Center / Karen C. Fox.

Greetings, Orbiter.ch

Japanese Cargo Craft Captured, Berthed to Station














JAXA - H-II Transfer Vehicle (HTV-4) mission patch / ISS - International Space Station patch.

Aug. 9, 2013


The fourth Japan Aerospace Exploration Agency H-II Transfer Vehicle, or HTV-4 was installed on its berthing port on the Earth-facing side of the International Space Station’s Harmony node at 11:38 a.m. EDT Friday, delivering 3.6 tons of science experiments, equipment and supplies to the orbiting complex.


Image above: The International Space Station's Canadarm2 grapples the unpiloted Japanese "Kounotori" H-II Transfer Vehicle-4 (HTV-4) as it approaches the station. Image Credit: NASA.

Flight Engineer Karen Nyberg, with the assistance of Flight Engineer Chris Cassidy, initially grappled the HTV-4 with the Canadian Space Agency-provided arm at 7:22 a.m. as the Japanese space freighter flew within about 30 feet of the complex. Flight Engineer Luca Parmitano of the European Space Agency joined the two NASA astronauts in the cupola to monitor the systems of the Japanese space freighter during its approach.


Image above: Robotics Workstation in the International Space Station’s Cupola, NASA astronaut Karen Nyberg, Expedition 36 flight engineer, participates in onboard training activity in preparation for the grapple and berthing of the Japanese "Kounotori" H2 Transfer Vehicle-4 (HTV-4). Image Credit: NASA.

At the time of capture, the station was orbiting 260 miles just to the south of South Africa.


Image above: The International Space Station's robotic arm, Canadarm2, moves the H-II Transfer Vehicle-4 into position for berthing on the Earth-facing port of the Harmony node. Image Credit: NASA TV.

With HTV-4 securely in the grasp of Canadarm2, the robotics team at the Johnson Space Center’s Mission Control Center remotely commanded the arm to guide HTV-4 to a ready-to-latch position on the Earth-facing port of the Harmony node.  Nyberg and Cassidy then used a laptop computer to conduct the initial bolting and first stage capture of Harmony’s Active Common Berthing Mechanism (ACBM) with HTV-4’s Passive Common Berthing Mechanism (PCBM).  Once that was done, the ground team completed the bolting process through second stage capture.

video
Japanese Cargo Ship Attached to ISS

Also known as Kounotori – Japanese for “white stork” because it is emblematic of an important delivery – the HTV is a 33-foot-long, 13-foot-diameter unmanned cargo transfer spacecraft capable of delivering both internal and external supplies and hardware to the station. HTV-4 launched from the Tanegashima Space Center in southern Japan on Aug.3 at 3:48 p.m. (Aug. 4 at 4:48 a.m., Japan time).

Read more about the launch of HTV-4: http://www.nasa.gov/content/japanese-space-freighter-heading-to-station/

Learn more about the HTV: http://www.nasa.gov/mission_pages/station/structure/elements/htv.html

After equalizing pressures between the cargo craft and the station, the crew is scheduled to open the hatches Saturday and begin the process of removing the supplies from the Kounotori’s pressurized logistics carrier.

Among the items within Kounotori’s pressurized section are test samples for research experiments inside the Kibo laboratory, a new freezer capable of preserving materials at temperatures below -90 F, four small CubeSat satellites to be deployed from Kibo’s airlock as well as food, water and other supplies for the station’s crew. The pressurized section also is delivering new hardware for the Robotic Refueling Mission to demonstrate robotic satellite-servicing tools, technologies and techniques.

Read about Robotic Refueling Mission hardware aboard HTV-4: http://www.nasa.gov/content/goddard/japanese-vehicle-delivers-new-hardware-for-nasa-s-robotic-refueling-mission/

The HTV-4’s unpressurized section is delivering two orbital replacement units (ORUs)  – a spare Main Bus Switching Unit (MBSU) and a spare Utility Transfer Assembly (UTA) –  to keep the space station’s electrical system operating smoothly.  The UTA maintains electrical continuity through the Solar Alpha Rotary Joint, passing electrical power generated by the complex’s huge solar arrays to station elements and payloads, while the MBSU provides switching capabilities for the various power channels and sources. ORUs are modular station components designed to be replaced periodically.


Image above: Flight Engineer Chris Cassidy monitors the installation of the H-II Transfer Vehicle-4 to the International Space Station's Harmony node. Image Credit: NASA TV.

Also inside HTV’s unpressurized cargo hold is the Space Test Program – Houston 4 (STP-H4) payload, which is a suite of seven experiments for investigating space communications, Earth monitoring and materials science.

The exposed pallet to which all the unpressurized cargo is mounted will be removed from Kounotori by Canadarm2, handed off to the Japanese Experiment Module robotic arm and attached to a platform on the Kibo module’s Exposed Facility over the weekend.

In early September, the cargo vehicle will be filled with trash, detached from the station and sent to burn up in Earth's atmosphere.

International Space Station website: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Video, Text, Credits: NASA / NASA TV.

Best regards, Orbiter.ch

Station Crew Captures Japanese Cargo Craft














JAXA - H-II Transfer Vehicle (HTV-4) mission patch / ISS - International Space Station patch.

Aug. 9, 2013

Using the International Space Station’s Canadian-built robotic arm, Expedition 36 Flight Engineer Karen Nyberg successfully captured the fourth Japan Aerospace Exploration Agency H-II Transfer Vehicle, or HTV-4, at 7:22 a.m. EDT Friday.

Working at the controls of the robotics workstation inside the station’s cupola while Flight Engineer Chris Cassidy provided assistance and communicated with the teams on the ground, Nyberg maneuvered Canadarm2 to grapple the HTV-4 cargo ship as it flew within about 30 feet of the complex. Flight Engineer Luca Parmitano of the European Space Agency joined the two NASA astronauts in the cupola to monitor the systems of the Japanese space freighter during the approach.


Image above: The International Space Station's robotic arm, Canadarm2, approaches the H-II Transfer Vehicle-4 for grapple. Image Credit: NASA TV.

At the time of capture, the station was south of South Africa and orbiting at an altitude of 260 miles.

With HTV-4 securely in the grasp of Canadarm2, the robotics team at the Johnson Space Center’s Mission Control Center will remotely command the arm to guide HTV-4 to a ready-to-latch position on the Earth-facing port of the Harmony node.  Nyberg and Cassidy will then use a laptop computer to conduct the initial bolting and first stage capture of Harmony’s Active Common Berthing Mechanism (ACBM) with HTV-4’s Passive Common Berthing Mechanism (PCBM).  Once that is done, the ground team will complete the bolting process through second stage capture.  NASA TV coverage of the berthing will begin at 9 a.m.

Watch NASA TV: http://www.nasa.gov/ntv

Also known as Kounotori, or “white stork,” because it is emblematic of an important delivery, HTV-4  is loaded with about 3.6 tons of equipment, supplies and experiments within its pressurized and unpressurized cargo sections. HTV-4 launched from the Tanegashima Space Center in southern Japan on Aug.3 at 3:48 p.m. (Aug. 4 at 4:48 a.m., Japan time).

After equalizing pressures between the cargo craft and the station, the crew is scheduled to open the hatches Saturday and begin the process of removing the supplies from the Kounotori’s pressurized logistics carrier.

video
Japanese Cargo Ship Arrives at ISS

Among the items within Kounotori’s pressurized section are test samples for research experiments inside the Kibo laboratory, a new freezer capable of preserving materials at temperatures below -90 F, four small CubeSat satellites to be deployed from Kibo’s airlock as well as food, water and other supplies for the station’s crew.

The HTV-4’s unpressurized section is delivering two orbital replacement units (ORUs)  – a spare Main Bus Switching Unit (MBSU) and a spare Utility Transfer Assembly (UTA) –  to keep the space station’s electrical system operating smoothly.  The UTA maintains electrical continuity through the Solar Alpha Rotary Joint, passing electrical power generated by the complex’s huge solar arrays to station elements and payloads, while the MBSU provides switching capabilities for the various power channels and sources. ORUs are modular station components designed to be replaced periodically.

Kibo module’s Exposed Facility description. Image credit:JAXA

Also inside HTV’s unpressurized cargo hold is the Space Test Program – Houston 4 (STP-H4) payload, which is a suite of seven experiments for investigating space communications, Earth monitoring and materials science.

Kibo module’s Exposed Facility. Image credit: NASA

The exposed pallet to which all the unpressurized cargo is mounted will be removed from Kounotori by Canadarm2, handed off to the Japanese Experiment Module robotic arm and attached to a platform on the Kibo module’s Exposed Facility over the weekend.

In early September, the cargo vehicle will be filled with trash, detached from the station and sent to burn up in Earth's atmosphere.

JAXA Mission website:

H-IIB Launch Vehicle: http://www.jaxa.jp/projects/rockets/h2b/index_e.html

H-II Transfer Vehicle "KOUNOTORI" (HTV): http://www.jaxa.jp/projects/rockets/htv/index_e.html

International Space Station website: http://www.nasa.gov/mission_pages/station/main/index.html

Images, Video, Text, Credits: NASA / NASA TV.

Greetings, Orbiter.ch

jeudi 8 août 2013

Hubble finds source of Magellanic Stream












ESA - Hubble Space Telescope logo.

8 August 2013

Astronomers explore origin of gas ribbon wrapped around our galaxy

Tracing the origin of the Magellanic Stream

Astronomers using the NASA/ESA Hubble Space Telescope have solved the 40-year-old mystery of the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around the Milky Way. New Hubble observations reveal that most of this stream was stripped from the Small Magellanic Cloud some two billion years ago, with a smaller portion originating more recently from its larger neighbour.

The Magellanic Clouds, two dwarf galaxies orbiting our galaxy, are at the head of a huge gaseous filament known as the Magellanic Stream. Since the Stream's discovery in the early 1970s, astronomers have wondered whether this gas comes from one or both of the satellite galaxies. Now, new Hubble observations show that most of the gas was stripped from the Small Magellanic Cloud about two billion years ago — but surprisingly, a second region of the stream was formed more recently from the Large Magellanic Cloud.

All-sky view of the Magellanic Stream (radio/visible-light)

A team of astronomers determined the source of the gas filament by using Hubble's Cosmic Origins Spectrograph (COS), along with observations from ESO's Very Large Telescope, to measure the abundances [1] of heavy elements, such as oxygen and sulphur, at six locations along the Magellanic Stream. COS detected these elements from the way they absorb the ultraviolet light released by faraway quasars as it passes through the foreground Stream. Quasars are the brilliant cores of active galaxies.

The team found low abundances of oxygen and sulphur along most of the stream, matching the levels in the Small Magellanic Cloud about two billion years ago, when the gaseous ribbon was thought to have been formed.

Overview of the Large Magellanic Cloud (ground-based image)

In a surprising twist, the team discovered a much higher level of sulphur in a region closer to the Magellanic Clouds. "We're finding a consistent amount of heavy elements in the stream until we get very close to the Magellanic Clouds, and then the heavy element levels go up," says Andrew Fox, a staff member supported by ESA at the Space Telescope Science Institute, USA, and lead author of one of two new papers reporting these results. "This inner region is very similar in composition to the Large Magellanic Cloud, suggesting it was ripped out of that galaxy more recently."

This discovery was unexpected; computer models of the Stream predicted that the gas came entirely out of the Small Magellanic Cloud, which has a weaker gravitational pull than its more massive cousin.

Small Magellanic Cloud (ground-based image)

"As Earth's atmosphere absorbs ultraviolet light, it's hard to measure the amounts of these elements accurately, as you need to look in the ultraviolet part of the spectrum to see them," says Philipp Richter of the University of Potsdam, Germany, and lead author on the second of the two papers. "So you have to go to space. Only Hubble is capable of taking measurements like these."

All of the Milky Way's nearby satellite galaxies have lost most of their gas content — except the Magellanic Clouds. As they are more massive than these other satellites they can cling on to this gas, using it to form new stars. However, these Clouds are approaching the Milky Way and its halo of hot gas. As they drift closer to us, the pressure of this hot halo pushes their gas out into space. This process, together with the gravitational tug-of-war between the two Magellanic Clouds, is thought to have formed the Magellanic Stream [2].

"Exploring the origin of such a large stream of gas so close to the Milky Way is important," adds Fox. "We now know which of our famous neighbours, the Magellanic Clouds, created this gas ribbon, which may eventually fall onto our own galaxy and spark new star formation. It's an important step forward in figuring out how galaxies obtain gas and form new stars."

Hubble Space Telescope in orbit

Notes:

[1] The "abundance" of an element is a measure of how common it is in its environment relative to other elements.

[2] The Magellanic Clouds can be used as a good testing ground for theories on how galaxies strip gas from one another and form new stars. This process seems episodic rather than smooth, without a continuous, slow stream of gas being stripped away from a small galaxy by a larger one. As both of the Magellanic Clouds are approaching our own galaxy, the Milky Way, they can be used to explore the dynamics of this process.

Notes for editors:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

These results are presented in a set of two papers, both published in the 1 August issue of The Astrophysical Journal.

The first of these papers is entitled "The COS/UVES absorption survey of the Magellanic Stream: I. One-tenth solar abundances along the body of the stream".

The international team of astronomers in this study consists of A. J. Fox (STScI, USA; ESA), P. Richter (University of Potsdam; Leibniz Institute for Astrophysics, Potsdam, Germany), B. P. Wakker (University of Wisconsin-Madison, USA), N. Lehner (University of Notre Dame, USA), J. C. Howk (University of Notre Dame, USA), N. B. Bekhti (University of Bonn, Germany), J. Bland-Hawthorn (University of Sydney, Australia), S. Lucas (University College London, UK).

The second of these papers is entitled "The COS/UVES absorption survey of the Magellanic Stream: II. Evidence for a complex enrichment history of the stream from the Fairall 9 sightline".

The international team of astronomers in this study consists of P. Richter (University of Potsdam; Leibniz Institute for Astrophysics, Potsdam, Germany), A. J. Fox (STScI, USA; ESA), B. P. Wakker (University of Wisconsin-Madison, USA), N. Lehner (University of Notre Dame, USA), J. C. Howk (University of Notre Dame, USA), J. Bland-Hawthorn (University of Sydney, Australia), N. B. Bekhti (University of Bonn, Germany), C. Fechner (University of Potsdam, Germany).

Links:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Research Paper I: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1314a.pdf

Research Paper II: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1314b.pdf

ESA Hubble website: http://www.spacetelescope.org/

NASA Hubble website: http://hubblesite.org/

Images, Text, Credits: ESA / NASA / Credit for the radio/visible light image: David L. Nidever, et al., NRAO / AUI / NSF and Mellinger, LAB Survey, Parkes Observatory, Westerbork Observatory, and Arecibo Observatory / Credit for the radio image: LAB Survey / ESO / Digitized Sky Survey 2. Acknowledgment: Davide De Martin.

Best regards, Orbiter.ch

mercredi 7 août 2013

If We Landed on Europa, What Would We Want to Know?













NASA - Voyager 1 & 2 Mission patch / NASA - Galileo Mission patch.

Aug. 7, 2013


Image above: This artist's concept shows a simulated view from the surface of Jupiter's moon Europa. Image Credit: NASA/JPL-Caltech.

Most of what scientists know of Jupiter's moon Europa they have gleaned from a dozen or so close flybys from NASA's Voyager 2 spacecraft in 1979 and NASA's Galileo spacecraft in the mid-to-late 1990s. Even in these fleeting, paparazzi-like encounters, scientists have seen a fractured, ice-covered world with tantalizing signs of a liquid water ocean under its surface. Such an environment could potentially be a hospitable home for microbial life. But what if we got to land on Europa's surface and conduct something along the lines of a more in-depth interview? What would scientists ask? A new study in the journal Astrobiology authored by a NASA-appointed science definition team lays out their consensus on the most important questions to address.

"If one day humans send a robotic lander to the surface of Europa, we need to know what to look for and what tools it should carry," said Robert Pappalardo, the study's lead author, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "There is still a lot of preparation that is needed before we could land on Europa, but studies like these will help us focus on the technologies required to get us there, and on the data needed to help us scout out possible landing locations. Europa is the most likely place in our solar system beyond Earth to have life today, and a landed mission would be the best way to search for signs of life."


Image above: This view of Jupiter's moon Europa features several regional-resolution mosaics overlaid on a lower resolution global view for context. Image Credit: NASA/JPL-Caltech/University of Arizona.

The paper was authored by scientists from a number of other NASA centers and universities, including the Johns Hopkins University Applied Physics Laboratory, Laurel, Md.; University of Colorado, Boulder; University of Texas, Austin; and the NASA Goddard Space Flight Center, Greenbelt, Md. The team found the most important questions clustered around composition: what makes up the reddish "freckles" and reddish cracks that stain the icy surface? What kind of chemistry is occurring there? Are there organic molecules, which are among the building blocks of life?

Additional priorities involved improving our images of Europa - getting a look around at features on a human scale to provide context for the compositional measurements. Also among the top priorities were questions related to geological activity and the presence of liquid water: how active is the surface? How much rumbling is there from the periodic gravitational squeezes from its planetary host, the giant planet Jupiter? What do these detections tell us about the characteristics of liquid water below the icy surface?

"Landing on the surface of Europa would be a key step in the astrobiological investigation of that world," said Chris McKay, a senior editor of the journal Astrobiology, who is based at NASA Ames Research Center, Moffett Field, Calif. "This paper outlines the science that could be done on such a lander. The hope would be that surface materials, possibly near the linear crack features, include biomarkers carried up from the ocean."

This work was conducted with Europa study funds from NASA's Science Mission Directorate, Washington, D.C. JPL is a division of the California Institute of Technology, Pasadena.

For more information about NASA's Voyager 1 & 2, visit: http://voyager.jpl.nasa.gov/ and http://voyager.jpl.nasa.gov/

For more information about NASA's Galileo, visit: http://solarsystem.nasa.gov/galileo/ and http://science1.nasa.gov/missions/galileo/

Images (mentioned), Text, Credits: NASA / JPL / Jia-Rui C. Cook.

Greetings, Orbiter.ch

The Odd Couple












ESO - European Southern Observatory logo.

7 August 2013

Two very different gas clouds in the galaxy next door

Two very different glowing gas clouds in the Large Magellanic Cloud

ESO’s Very Large Telescope has captured an intriguing star-forming region in the Large Magellanic Cloud — one of the Milky Way’s satellite galaxies. This sharp image reveals two distinctive glowing clouds of gas: red-hued NGC 2014, and its blue neighbour NGC 2020. While they are very different, they were both sculpted by powerful stellar winds from extremely hot newborn stars that also radiate into the gas, causing it to glow brightly.

This image was taken by the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile — the best place in the southern hemisphere for astronomical observing. But even without the help of telescopes like the VLT, a glance towards the southern constellation of Dorado (The Swordfish or Dolphinfish [1]) on a clear, dark night reveals a blurry patch which, at first sight, appears to be just like a cloud in the Earth's atmosphere.

An odd couple of glowing gas clouds in the constellation of Dorado

At least, this may have been explorer Ferdinand Magellan's first impression during his famous voyage to the southern hemisphere in 1519. Although Magellan himself was killed in the Philippines before his return, his surviving crew announced the presence of this cloud and its smaller sibling when they returned to Europe, and these two small galaxies were later named in Magellan's honour. However, they were undoubtedly seen by both earlier European explorers and observers in the southern hemisphere, although they were never reported.

The Large Magellanic Cloud (LMC) is actively producing new stars. Some of its star-forming regions can even be seen with the naked eye, for example, the famous Tarantula Nebula. However, there are other smaller — but no less intriguing — regions that telescopes can reveal in intricate detail. This new VLT image explores an oddly mismatched pair: NGC 2014 and NGC 2020.

Wide-field view of NGC 2014 and NGC 2020 in the Large Magellanic Cloud

The pink-tinged cloud on the right, NGC 2014, is a glowing cloud of mostly hydrogen gas. It contains a cluster of hot young stars. The energetic radiation from these new stars strips electrons from the atoms within the surrounding hydrogen gas, ionising it and producing a characteristic red glow.

In addition to this strong radiation, massive young stars also produce powerful stellar winds that eventually cause the gas around them to disperse and stream away. To the left of the main cluster, a single brilliant and very hot star [2] seems to have started this process, creating a cavity that appears encircled by a bubble-like structure called NGC 2020. The distinctive blueish colour of this rather mysterious object is again created by radiation from the hot star — this time by ionising oxygen instead of hydrogen.

video
Zooming in on glowing gas clouds NGC 2014 and NGC 2020

The strikingly different colours of NGC 2014 and NGC 2020 are the result of both the different chemical makeup of the surrounding gas and the temperatures of the stars that are causing the clouds to glow. The distances between the stars and the respective gas clouds also play a role.

The LMC is only about 163 000 light-years from our galaxy, the Milky Way, and so is very close on a cosmic scale. This proximity makes it a very important target for astronomers, as it can be studied in far more detail than more distant systems. It was one of the motivations for building telescopes in the southern hemisphere, which led to the establishment of ESO over 50 years ago. Although enormous on a human scale, the LMC contains less than one tenth of the mass of the Milky Way, and spans just 14 000 light-years — by contrast, the Milky Way covers some 100 000 light-years. Astronomers refer to the LMC as an irregular dwarf galaxy; its irregularity, combined with its prominent central bar of stars, suggests that interactions with the Milky Way and another nearby galaxy, the Small Magellanic Cloud, could have caused its chaotic shape.

video
Pan across new VLT image of NGC 2014 and NGC 2020

This image was acquired using the visual and near-ultraviolet FOcal Reducer and low dispersion Spectrograph (FORS2) instrument attached to ESO's VLT, as part of the ESO Cosmic Gems programme [3].

Notes:

[1] Although this constellation is often identified with the swordfish there are reasons to think that the less commonly known dolphinfish may be a better match. More details are given here.

[2] This star is an example of a rare class called Wolf-Rayet stars. These short-lived objects are very hot — their surfaces can be more than ten times as hot as the surface of the Sun — and very bright and dominate the regions around them.

[3] This picture comes from the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

More information:

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESO Cosmic Gems programme: http://www.eso.org/public/outreach/gems.html

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Images taken with FORS: http://www.eso.org/public/images/archive/search/?adv=&instrument=3&instrument=4

Images taken with the VLT: http://www.eso.org/public/images/archive/search/?adv=&facility=31

Images, Text, Credits: ESO / IAU and Sky & Telescope / Digitized Sky Survey 2. Acknowledgement: Davide De Martin / Videos: ESO/Nick Risinger (skysurvey.org)/Digitized Sky Survey 2. Music: John Dyson.

Best regards, Orbiter.ch

lundi 5 août 2013

Astronomers Image Lowest-mass Exoplanet Around a Sun-like Star












SUBARU - National Astronomical Observatory of Japan logo.


Aug. 5, 2013

Using infrared data from the Subaru Telescope in Hawaii, an international team of astronomers has imaged a giant planet around the bright star GJ 504. Several times the mass of Jupiter and similar in size, the new world, dubbed GJ 504b, is the lowest-mass planet ever detected around a star like the sun using direct imaging techniques.


Image above: Glowing a dark magenta, the newly discovered exoplanet GJ 504b weighs in with about four times Jupiter's mass, making it the lowest-mass planet ever directly imaged around a star like the sun. Image Credit: NASA's Goddard Space Flight Center/S. Wiessinger.

"If we could travel to this giant planet, we would see a world still glowing from the heat of its formation with a color reminiscent of a dark cherry blossom, a dull magenta," said Michael McElwain, a member of the discovery team at NASA's Goddard Space Flight Center in Greenbelt, Md. "Our near-infrared camera reveals that its color is much more blue than other imaged planets, which may indicate that its atmosphere has fewer clouds."

GJ 504b orbits its star at nearly nine times the distance Jupiter orbits the sun, which poses a challenge to theoretical ideas of how giant planets form.


Image above: This composite combines Subaru images of GJ 504 using two near-infrared wavelengths (orange, 1.6 micrometers, taken in May 2011; blue, 1.2 micrometers, April 2012). Once processed to remove scattered starlight, the images reveal the orbiting planet, GJ 504b. Image Credit: NASA’s Goddard Space Flight Center / NOAJ.

According to the most widely accepted picture, called the core-accretion model, Jupiter-like planets get their start in the gas-rich debris disk that surrounds a young star. A core produced by collisions among asteroids and comets provides a seed, and when this core reaches sufficient mass, its gravitational pull rapidly attracts gas from the disk to form the planet.

While this model works fine for planets out to where Neptune orbits, about 30 times Earth's average distance from the sun (30 astronomical units, or AU), it's more problematic for worlds located farther from their stars. GJ 504b lies at a projected distance of 43.5 AU from its star; the actual distance depends on how the system tips to our line of sight, which is not precisely known.

"This is among the hardest planets to explain in a traditional planet-formation framework," explained team member Markus Janson, a Hubble postdoctoral fellow at Princeton University in New Jersey. "Its discovery implies that we need to seriously consider alternative formation theories, or perhaps to reassess some of the basic assumptions in the core-accretion theory."

The research is part of the Strategic Explorations of Exoplanets and Disks with Subaru (SEEDS), a project to directly image extrasolar planets and protoplanetary disks around several hundred nearby stars using the Subaru Telescope on Mauna Kea, Hawaii. The five-year project began in 2009 and is led by Motohide Tamura at the National Astronomical Observatory of Japan (NAOJ).


Image above: This chart locates the fifth-magnitude star GJ 504, also known as 59 Virginis, which is visible to the unaided eye from suburban skies. Image Credit: NASA’s Goddard Space Flight Center.

While direct imaging is arguably the most important technique for observing planets around other stars, it is also the most challenging.

"Imaging provides information about the planet’s luminosity, temperature, atmosphere and orbit, but because planets are so faint and so close to their host stars, it's like trying to take a picture of a firefly near a searchlight," explained Masayuki Kuzuhara at the Tokyo Institute of Technology, who led the discovery team.

The SEEDS project images at near-infrared wavelengths with the help of the telescope's novel adaptive optics system, which compensates for the smearing effects of Earth's atmosphere, and two instruments: the High Contrast Instrument for the Subaru Next Generation Adaptive Optics and the InfraRed Camera and Spectrograph. The combination allows the team to push the boundary of direct imaging toward fainter planets.

A paper describing the results has been accepted for publication in The Astrophysical Journal and will appear in a future issue.

Subaru Telescope in Hawaii. Image credit: NASA / SUBARU

The researchers find that GJ 504b is about four times more massive than Jupiter and has an effective temperature of about 460 degrees Fahrenheit (237 Celsius).

It orbits the G0-type star GJ 504, which is slightly hotter than the sun and is faintly visible to the unaided eye in the constellation Virgo. The star lies 57 light-years away and the team estimates the systems is about 160 million years, based on methods that link the star's color and rotation period to it age.

Young star systems are the most attractive targets for direct exoplanet imaging because their planets have not existed long enough to lose much of the heat from their formation, which enhances their infrared brightness.

"Our sun is about halfway through its energy-producing life, but GJ504 is only one-thirtieth its age," added McElwain. "Studying these systems is a little like seeing our own planetary system in its youth."

Related Links:

Paper (preprint): Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504: http://arxiv.org/abs/1307.2886

Related multimedia from NASA Goddard's Scientific Visualization Studio: http://svs.gsfc.nasa.gov/goto?11327

Subaru Telescope press release: http://subarutelescope.org/Pressrelease/2013/08/04/index.html

List of imaged exoplanets in The Extrasolar Planets Encyclopaedia: http://exoplanet.eu/catalog/?f=%22imaging%22+IN+detection

"Astronomers Directly Image Massive Star's 'Super-Jupiter'" (11.19.12): http://www.nasa.gov/topics/universe/features/super-jupiter.html

"Spiral Arms Point to Possible Planets in a Star's Dusty Disk" (10.19.11): http://www.nasa.gov/topics/universe/features/possible-planets.html

Images (mentioned), Text, Credits: NASA / Goddard Space Flight Center / Francis Reddy.

Greetings, Orbiter.ch

International Charter provides Pléiades imagery over the Lac-Mégantic disaster

















CSA-ASC - Canadian Space Agency logo / International Charter Space & Major Disasters logo.

August 5, 2013

Canada has obtained a very high resolution image of the Lac-Mégantic train wreck, which was captured on July 13 by Pléiades, a satellite of the CNES, the French space agency. This picture was taken after Public Safety Canada activated the International Charter on Space and Major Disasters, in which the Canadian Space Agency (CSA) is actively involved. The data shared in the context of the Charter help damage assessment and support recovery efforts.


International Charter provides Pléiades imagery over the Lac-Mégantic disaster / Image Pléiades du désastre à Lac-Mégantic fournie par la Charte internationale. (Click on the image for enlarge / cliquez sur l'image pour agrandir).

This image is available on the CSA Website: http://www.asc-csa.gc.ca/eng/default.asp#train-disaster

About the CSA and Disaster Management:

Canadian satellites are key resources in a variety of disaster management scenarios. The data they contribute regularly in the context of the Charter has been used effectively in disaster responses such as earthquakes, tsunamis, floods, landslides, forest fires, and other natural or technological disasters. The ability to deliver data in near-real time is essential for relief operations to map and monitor damage and for assessing the impact on the future.

Pléiades satellite

En français pour mes amis Québecois:

Image Pléiades du désastre à Lac-Mégantic fournie par la Charte internationale

Le Canada a obtenu une image à très haute résolution du désastre ferroviaire à Lac-Mégantic, acquise le 13 juillet par le satellite Pléiades du Centre National d’Études Spatiales (CNES), l’agence spatiale française. Cette photo a été prise suivant l’activation par Sécurité publique Canada de la Charte internationale Espace et catastrophes majeures à laquelle l’Agence spatiale canadienne (ASC) participe activement. Les données partagées dans le cadre de cette Charte permettent de faciliter l’évaluation des dommages et d’aider la reconstruction.

Carte animée / Animated map


Cette image est disponible sur le site Web de l’ASC: http://www.asc-csa.gc.ca/fra/default.asp#desastre

À propos de l’ASC et de la gestion des catastrophes :

Les satellites canadiens constituent des ressources clés lorsque vient le temps de gérer divers types de catastrophes. Les données qu’ils fournissent régulièrement dans le cadre de la Charte sont utilisées pour faciliter l'organisation des secours lors de catastrophes telles des tremblements de terre, des tsunamis, des inondations, des glissements de terrain, des feux de forêt et d'autres catastrophes naturelles ou technologiques. Les données fournies en temps quasi réel sont essentielles à l'organisation des secours, aux activités de cartographie et de surveillance des dommages causés par la catastrophe, et à l'évaluation de leur incidence pour l'avenir.

Pour plus d'informations sur l'Agence Spatiale Canadienne, visitez le site de l'ASC / For more information about Canadian Space Agency, visit the CSA website: http://www.asc-csa.gc.ca/index.html

Images, Text, Credits: CSA-ASC / CNES.

Best regards, cordiales salutations, Orbiter.ch

Alphasat deploys its Giant Reflector in orbit








ESA - Alphasat logo.

5 August 2013

Alphasat, Europe’s largest-ever telecom satellite, reached a temporary position in the geostationary ring last weekend, where it deployed its 11 m-diameter main antenna over the course of a day – marking ten days in orbit and completing one of the final steps towards starting services.

It will stay in this slot for several weeks while Inmarsat together with ESA continue testing the telecom payload, the backup units on the Alphabus platform and ESA’s four hosted payloads.

Several major milestones have been met over the past few days, including rising to geostationary altitude after separation from its Ariane 5 launcher, and deploying its twin four-panel solar wings, spanning 40 m.

The panels rotate automatically, following the Sun, while Alphasat’s sophisticated attitude control system tracks its position above Earth.

Alphasat artist's impression

All of these milestones were assured by a team from Astrium, the Alphasat prime contractor, managed by Inmarsat. In a cooperative effort unprecedented in Europe, the team was supported by ESA and France’s CNES space agency, as well as Thales Alenia Space for Alphabus platform operations.

Alphasat uses the first flight model of the new platform. The Alphabus line, developed by Astrium and Thales Alenia Space, under a joint contract to ESA and CNES, is Europe’s response to market demand for increased broadcasting services.

It accommodates missions with up to 22 kW of payload power and mass up to two tonnes. As a high-power multipurpose platform, it gives European industry an unprecedented and unique position in the global telecom market.

Jena-Optonik’s Astro APS startracker was the first hosted payload to be switched on, measuring the satellite’s attitude.

Alphasat joins Inmarsat’s award-winning I-4 satellite fleet, which has been powering global broadband connectivity for government and commercial customers in the L-band since 2009.

The new satellite with its new-generation advanced payload will provide additional mobile satellite communications capacity over Europe, the Middle East and Africa.

Related links:

The Alphabus platform: http://www.esa.int/Our_Activities/Telecommunications_Integrated_Applications/Alphasat/Platform

Alphasat in pictures: http://spaceinimages.esa.int/content/search?SearchText=Alphasat&img=1&SearchButton=Go

Alphasat in video: http://spaceinvideos.esa.int/content/search?SearchText=Alphasat&SearchButton=Go

Image, Text, Credit: ESA.

Greetings, Orbiter.ch

Sunset in Mordor












ESA -Hubble Space Telescope patch.

5 August 2013

 A star is born

Don’t be fooled by the title; the mysterious, almost mystical bright light emerging from these thick, ominous clouds is actually a telltale sign of forming stars.

Here, a very young star is being born in the guts of the dark cloud LDN 43 – a massive blob of gas, dust and ices, gathered 520 light-years from Earth in the constellation of Ophiuchus, The Serpent Bearer.

Stars are born from cosmic dust and gas, which float freely in space until gravity forces it to bind together. The newborn star, RNO 91, is hidden in this image, revealed only by light reflected onto the plumes of the dark cloud. It is what astronomers call a pre-main sequence star, meaning that it has not yet started burning hydrogen in its core.

The energy that allows RNO 91 to shine comes from gravitational contraction – the star is being compressed by its own weight. Once a critical mass is reached, hydrogen, its main component, will begin to fuse together, releasing huge amounts of energy in the process. This will mark the beginning of adulthood for the star.

But even before this happens the adolescent star is bright enough to shine and generate powerful stellar winds, emitting intense X-ray and radio emission.

RNO 91 is a variable star around half the mass of the Sun. Astronomers have already seen a dusty, icy disc surrounding it, stretching out to over 1700 times the distance from Earth to the Sun. It is believed that this disc may host planet embryos, and that it will eventually evolve into a fully-fledged planetary system.

Hubble Space Telescope

This image is based on data gathered by the NASA/ESA Hubble Space Telescope. A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Related links:

Hubble’s Hidden: Treasures: http://www.spacetelescope.org/projects/hiddentreasures/

Hubble overview: http://www.esa.int/Our_Activities/Space_Science/Hubble_overview

Hubble in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=31

For more information about NASA / ESA Hubble Space Telescope: http://www.nasa.gov/hubble and http://www.spacetelescope.org/

Images, Text, Credits: ESA / Hubble & NASA; Acknowledgement: J. Schmidt.

Greetings, Orbiter.ch