vendredi 27 novembre 2015

Release the beams! Linac 4 hits the 50 MeV mark

CERN - European Organization for Nuclear Research logo.

November 27, 2015

Image above: The Linac 4 tunnel where DTL tubes guide the 50MeV beam, taken on the Photowalk. (Image: Andrew Hara/CERN).

This week the Linac 4 accelerator has reached a milestone energy of 50 MeV – meaning it is now able to replace the ageing Linac 2 and eventually become the head of the accelerator chain .

Linac 4 was built to boost negative hydrogen ions – consisting of a hydrogen atom with an additional electron – to high energies to provide protons to the Large Hadron and to replace the  Linac 2. This 37-year-old accelerator is the first in a series of four, which are boosting particles to higher and higher energies before they are injected into the Large Hadron Collider (LHC). These accelerators are also providing beams to many other experiments at CERN.

Eventually Linac 4 will accelerate ions to 160 MeV to prepare them to enter the Proton Synchrotron Booster – the second acclerator in the LHC injection chain. These ions are stripped of their two electrons during injection from Linac 4 into the Proton Synchrotron Booster to leave only protons. This allows more particles to accumulate in the synchrotron, simplifies injection, reduces beam loss at injection and gives a more brilliant beam. As a key part of the LHC injector upgrade programme, Linac 4 will allow the PS Booster to double its beam brightness, which will contribute to increasing the LHC’s luminosity, a crucial factor proportional to the number of particles colliding within a defined amount of time.

Image above: A photo montage from the 2015 photowalk, with Maurizio Vretenar, the Linac 4 project leader, alongside both the designs for and the constructed accelerator  2015. (Image: Maelle Baud/CERN).

Reaching 50MeV is a milestone as it’s the energy Linac 2 runs at, and means Linac4 is now capable of taking over the task of providing particles to CERN’s accelerator chain – a process that will begin during the long shutdown from 2018.

The Linac 4 is composed of a hydrogen ion source and four types of accelerating structures which are progressively commissioned one after another. Earlier this year the second part of this accelerating chain, the Drift Tube Linac tanks were fully installed and commissioned, meaning the beam could be boosted to a new, higher, energy from its previous 3 MeV.

“This innovative and patented design is a huge achievement that was eight years in the making,” says Maurizio Vretenar, the Linac 4 project leader. “We saw these tanks through from the drawing board to the test bench, and now to the accelerator chain itself; we couldn’t be happier with their performance so far.”

Ensuring faultless connections between the seperate accelerator components was a key part of the commissioning process. The tubes and their components had to be aligned with ±0.1 mm precision to each other and to the rest of the Linac 4 line.

“The first step was to accelerate the beam through the first tank of the DTL, to find the correct settings of the low energy part,” says Alessandra Lombardi, who is in charge of the commissioning phase of Linac 4. We then accelerated the beam progressively through the second and the third tank to the energy of 50 MeV.”

Now the beam has reached 50 MeV, the Linac 4 team is moving on to the next item on the schedule: the Cell-Coupled DTLs (CCDTL), which will bring Linac 4 up to 100 MeV.


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

Linac 4 accelerator:

 Linac 2 accelerator:

Proton Synchrotron Booster:

For more information about European Organization for Nuclear Research (CERN), visit:

Images (mentioned), Text, Credits: CERN/Harriet Kim Jarlett.


LHC collides ions at new record energy

CERN - European Organization for Nuclear Research logo.

November 27, 2015

Lead ions collide in the CMS detector. (Image: CMS)

After the successful restart of the Large Hadron Collider (LHC) and its first months of data taking with proton collisions at a new energy frontier, the LHC is moving to a new phase, with the first lead-ion collisions of season 2 at an energy about twice as high as that of any previous collider experiment. Following a period of intense activity to re-configure the LHC and its chain of accelerators for heavy-ion beams, CERN’s accelerator specialists put the beams into collision for the first time in the early morning of 17 November 2015 and ‘stable beams’ were declared at 10.59 am on 26 November 2015, marking the start of a one-month run with positively charged lead ions: lead atoms stripped of electrons. The four large LHC experiments will all take data over this campaign, including LHCb, which will record this kind of collision for the first time. Colliding lead ions allows the LHC experiments to study a state of matter that existed shortly after the big bang, reaching a temperature of several trillion degrees.

Lead ions collide in the ALICE detector. (Image: ALICE)

“It is a tradition to collide ions over one month every year as part of our diverse research programme at the LHC,” said CERN Director-General Rolf Heuer. “This year however is special as we reach a new energy and will explore matter at an even earlier stage of our universe.”

Early in the life of our universe, for a few millionths of a second, matter was a very hot and very dense medium – a kind of primordial ‘soup’ of particles, mainly composed of fundamental particles known as quarks and gluons. In today’s cold Universe, the gluons “glue” quarks together into the protons and neutrons that form bulk matter, including us, as well as other kinds of particles.

“There are many very dense and very hot questions to be addressed with the ion run for which our experiment was specifically designed and further improved during the shutdown,” said ALICE collaboration spokesperson Paolo Giubellino. “For instance, we are eager to learn how the increase in energy will affect charmonium production, and to probe heavy flavour and jet quenching with higher statistics. The whole collaboration is enthusiastically preparing for a new journey of discovery.”

Lead ions collide in the LHCb detector. (Image: LHCb)

Increasing the energy of collisions will increase the volume and the temperature of the quark and gluon plasma, allowing for significant advances in understanding the strongly-interacting medium formed in lead-ion collisions at the LHC. As an example, in season 1 the LHC experiments confirmed the perfect liquid nature of the quark-gluon plasma and the existence of “jet quenching” in ion collisions, a phenomenon in which generated particles lose energy through the quark-gluon plasma. The high abundance of such phenomena will provide the experiments with tools to characterize the behaviour of this quark-gluon plasma. Measurements to higher jet energies will thus allow new and more detailed characterization of this very interesting state of matter.

“The heavy-ion run will provide a great complement to the proton-proton data we've taken this year," said ATLAS collaboration spokesperson Dave Charlton. "We are looking forward to extending ATLAS' studies of how energetic objects such as jets and W and Z bosons behave in the quark gluon plasma.”

Lead ions collide in the ATLAS dectector. (Image: ATLAS/CERN)

The LHC detectors were substantially improved during the LHC’s first long shutdown. With higher statistics expected, physicists will be able to look deeper at the tantalising signals observed in season 1.

"Heavy flavour particles will be produced at high rate in Season 2, opening up unprecedented opportunities to study hadronic matter in extreme conditions,” said CMS collaboration spokesperson Tiziano Camporesi. « CMS is ideally suited to trigger on these rare probes and to measure them with high precision. »

For the very first time, the LHCb collaboration will join the club of experiments taking data with ion-ion collisions.

"This is an exciting step into the unknown for LHCb, which has very precise particle identification capabilities. Our detector will enable us to perform measurements t

hat are highly complementary to those of our friends elsewhere around the ring,” said LHCb collaboration spokesperson Guy Wilkinson.

Read more: "A new energy frontier for heavy ions" – Opinion piece by accelerator physicist John Jowett:


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

Large Hadron Collider (LHC):

LHCb experiments:

ALICE experiments:

ATLAS experiments:

CMS experiment:

Quark and gluon plasma:

For more information about European Organization for Nuclear Research (CERN), visit:

Images (mentioned), Text, Credits: CERN/Cian O'Luanaigh.

Best regards,

The Ins and Outs of NASA’s First Launch of SLS and Orion

NASA - Space Launch System (SLS) logo.

Nov. 27, 2015

NASA is hard at work building the Orion spacecraft, Space Launch System (SLS) rocket and the ground systems needed to send astronauts into deep space. The agency is developing the core capabilities needed to enable the journey to Mars.

Orion’s first flight atop the SLS will not have humans aboard, but it paves the way for future missions with astronauts. Ultimately, it will help NASA prepare for missions to the Red Planet. During this flight, currently designated Exploration Mission-1 (EM-1), the spacecraft will travel thousands of miles beyond the moon over the course of about a three-week mission.

It will launch on the most powerful rocket in the world and fly farther than any spacecraft built for humans has ever flown. Orion will stay in space longer than any ship for astronauts has done without docking to a space station and return home faster and hotter than ever before.

Image above: NASA¹s Space Launch System rocket will launch with Orion atop it from Launch Complex 39B at NASA¹s modernized spaceport at Kennedy Space Center in Florida. Image Credit: NASA.

“This is a mission that truly will do what hasn’t been done and learn what isn’t known,” said Mike Sarafin, EM-1 mission manager at NASA Headquarters in Washington. “It will blaze a trail that people will follow on the next Orion flight, pushing the edges of the envelope to prepare for that mission.”

SLS and Orion will blast off from Launch Complex 39B at NASA’s modernized spaceport at Kennedy Space Center in Florida. The spacecraft will deploy its solar arrays and the SLS upper stage, called the Interim Cryogenic Propulsion Stage (ICPS). This will give Orion the big push needed to leave Earth’s orbit and travel toward the moon. From there, Orion will separate from the ICPS. The ICPS will then deploy a number of small satellites, known as CubeSats, to perform several experiments and technology demonstrations.

As Orion continues on its path from Earth orbit to the moon, it will be propelled by a service module provided by the European Space Agency, which will supply the spacecraft’s main propulsion system and power (as well as house air and water for astronauts on future missions). Orion will pass through the Van Allen radiation belts, fly past the Global Positioning System (GPS) satellite constellation and above communication satellites in Earth orbit. To talk with mission control in Houston, Orion will switch from NASA’s Tracking and Data Relay System satellites and, for the first time for a human spaceflight vehicle in decades, communicate through the Deep Space Network.

The outbound trip to the moon will take several days, during which time engineers will evaluate the spacecraft’s systems and, as needed, correct its trajectory. Orion will fly about 62 miles (100 km) above the surface of the moon, and then use the moon’s gravitational force to propel Orion into a new deep retrograde, or opposite, orbit about 40,000 miles (70,000 km) from the moon.

Image above: During Exploration Mission-1, Orion will venture thousands of miles beyond the moon during an approximately three week mission. Image Credit: NASA.

The spacecraft will stay in that orbit for approximately six days to collect data and allow mission controllers to assess the performance of the spacecraft. During this period, Orion will travel in a direction around the moon retrograde from the direction the moon travels around Earth.

For its return trip to Earth, Orion will do another close flyby that takes the spacecraft within about 60 miles of the moon’s surface, the spacecraft will use another precisely timed engine firing of the European-provided service module in conjunction with the moon’s gravity to accelerate back toward Earth. This maneuver will set the spacecraft on its trajectory back toward Earth to enter our planet’s atmosphere traveling at 25,000 mph (11 kilometers per second), producing temperatures of approximately 5,000 degrees Fahrenheit (2,760 degrees Celsius) – faster and hotter than Orion experienced during its 2014 flight test. The spacecraft will splashdown in the Pacific Ocean off the San Diego coast.

This first exploration mission will allow NASA to use the lunar vicinity as a proving ground to test technologies farther from Earth, and demonstrate it can get to a stable orbit in the area of space near the moon in order to support sending humans to deep space, including for the Asteroid Redirect Mission. NASA and its partners will use this proving ground to practice deep-space operations with decreasing reliance on the Earth and gaining the experience and systems necessary to make the journey to Mars a reality.

Related links:

Interim Cryogenic Propulsion Stage (ICPS):

Space Launch System (SLS):

Orion Spacecraft:

Ground Systems:

Deep Space Network (DSN):

Journey to Mars:

Van Allen radiation belts:

Images (mentioned), Text, Credits: NASA/Daniel Huot.

Best regards,

A Precocious Black Hole

NASA - Chandra X-ray Observatory patch / ESA - XMM-Newton Mission patch.

Nov. 27, 2015

In July 2015, researchers announced the discovery of a black hole, shown in the above illustration, that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on the development of galaxies. The black hole was originally discovered using NASA's Hubble Space Telescope, and was then detected in the Sloan Digital Sky Survey and by ESA's XMM-Newton and NASA's Chandra X-ray Observatory.

Benny Trakhtenbrot, from ETH Zurich's Institute for Astronomy, and an international team of astrophysicists, performed a follow-up observation of this black hole using the 10 meter Keck telescope in Hawaii and were surprised by the results. The data, collected with a new instrument, revealed a giant black hole in an otherwise normal, distant galaxy, called CID-947.

Read Chandra X-Ray Observatory CID-947 full article:

For more information about Chandra X-Ray Observatory, visit:

For more information about XMM-Newton, visit:

Illustration Credits: M. Helfenbein, Yale University/OPAC/Text, Credits: NASA/Chandra X-Ray Observatory/Sarah Loff.


jeudi 26 novembre 2015

Station Crew Getting Ready for Heavy Traffic Before Christmas

ISS - Expedition 45 Mission patch.

November 26, 2015

Crews and cargo shipments will be coming and going at the International Space Station during a busy December in space. Two resupply ships will arrive, one cargo craft will leave and an Expedition 45 trio will head home before an Expedition 46 trio replaces it.

Commander Scott Kelly teamed up with Flight Engineer Kjell Lindgren for more robotics training before the Dec. 3 launch and Dec. 6 arrival of the Orbital ATK Cygnus cargo craft. When Cygnus arrives it will be captured with the Canadarm2 robotic arm and berthed to the Unity module.

Image above: The current space station configuration has two Soyuz crew spacecraft and two Progress resupply ships docked at the orbital laboratory. Image Credit: NASA.

Meanwhile, Lindgren along with Japanese astronaut Kimiya Yui and Soyuz Commander Oleg Kononenko are preparing for their Dec. 11 landing. On the ground in Russia, their Expedition 46 replacements Soyuz Commander Yuri Malenchenko and Flight Engineers Timothy Kopra and Timothy Peake are counting down to their Dec. 15 launch. A docked Progress 61 resupply ship will fire its engines Wednesday raising the station’s orbit to accommodate the mid-December crew swap.

The Cygnus cargo craft is in Florida at the Kennedy Space Center being processed before its early December launch atop an Atlas V rocket. Russia’s Progress 60 (60P) cargo craft will undock from the Pirs docking compartment Dec. 19. A new Progress 62 resupply ship will replace the 60P when it arrives at Pirs Dec. 23.

Related links:

Crews and cargo shipments:

One-Year Crew:

Expedition 45:

For more information about the International Space Station, visit:

Image (mentioned), Text, Credits: NASA/Mark Garcia.


mercredi 25 novembre 2015

Cargo ship Progress M-29M adjust the ISS orbit

ROSCOSMOS - Russian Vehicles patch.


In accordance with the flight to the International Space Station (ISS) November 25, 2015 has been successfully carried out correction of the ISS orbit.

The purpose of correction - the configuration of the working station's orbit for 4 docking scheme with the future arrival of the manned spacecraft Soyuz TMA-19M with the ISS 15 December 2015.

International Space Station (ISS). Image Credit: NASA

Launch of TPK Soyuz TMA-19M to the ISS scheduled for December 15, 2015 at 14 hours 3 minutes Moscow time from the Baikonur Cosmodrome. The docking of the WPK Soyuz TMA-19M with the station module MIM-1 "Dawn" is scheduled for December 15, 20 hours 23 minutes Moscow Time.

ROSCOSMOS Press Release:

Image (mentioned), Text, Credits: ROSCOSMOS/Translation: Aerospace.


SDO Sees a Dark Filament Circle

NASA - Solar Dynamics Observatory (SDO) patch.

Nov. 25, 2015

SDO Sees a Dark Filament Circle. Video Credits: NASA/SDO

A dark, almost circular filament broke away from the sun in a gauzy, feathery swirl, on Nov. 15, 2015, in this video from NASA’s Solar Dynamics Observatory. This filament eruption was followed by a second filament breaking away on Nov. 16.

SDO Sees a Dark Filament Circle. Image Credits: NASA/SDO

Filaments are dark strands of plasma tethered above the sun’s surface by magnetic forces that, over time, often become disrupted and break away from the sun. Filaments appear darker than the surrounding material because of their comparatively cool temperature. This video was taken in extreme ultraviolet wavelengths of 304 angstroms and colorized in red.

For more information about Solar Dynamics Observatory (SDO), visit:

Image (mentioned), Video (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Steele Hill/Sarah Frazier/Rob Garner.

Best regards,

Hubble Captures a Galactic Waltz

NASA - Hubble Space Telescope patch.

Nov. 25, 2015

This curious galaxy — only known by the seemingly random jumble of letters and numbers 2MASX J16270254+4328340 — has been captured by the NASA/ESA Hubble Space Telescope dancing the crazed dance of a galactic merger. The galaxy has merged with another galaxy leaving a fine mist, made of millions of stars, spewing from it in long trails.

Despite the apparent chaos, this snapshot of the gravitational tango was captured towards the event’s conclusion. This transforming galaxy is heading into old age with its star-forming days coming to an end. The true drama occurred earlier in the process, when the various clouds of gas within the two galaxies were so disturbed by the event that they collapsed, triggering an eruption of star formation. This flurry of activity exhausted the vast majority of the galactic gas, leaving the galaxy sterile and unable to produce new stars.

As the violence continues to subside, the newly formed galaxy’s population of stars will redden with age and eventually begin to cool and dim one by one. With no future generations of stars to take their place, the galaxy thus begins a steady path of fading and quieting.

Hubble Space Telescope. Image Credit: NASA

For images and more information about Hubble, visit: and and

Image, Text, Credits: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt/Text Credits: European Space Agency/Ashley Morrow.


Aging Star’s Weight Loss Secret Revealed

ESO - European Southern Observatory logo.

25 November 2015

Giant star caught in the act of slimming down

VLT image of the surroundings of VY Canis Majoris seen with SPHERE

A team of astronomers using ESO’s Very Large Telescope (VLT) has captured the most detailed images ever of the hypergiant star VY Canis Majoris. These observations show how the unexpectedly large size of the particles of dust surrounding the star enable it to lose an enormous amount of mass as it begins to die. This process, understood now for the first time, is necessary to prepare such gigantic stars to meet explosive demises as supernovae.

VY Canis Majoris is a stellar goliath, a red hypergiant, one of the largest known stars in the Milky Way. It is 30–40 times the mass of the Sun and 300 000 times more luminous. In its current state, the star would encompass the orbit of Jupiter, having expanded tremendously as it enters the final stages of its life.

The red hypergiant star VY Canis Majoris

The new observations of the star used the SPHERE instrument on the VLT. The adaptive optics system of this instrument corrects images to a higher degree than earlier adaptive optics systems. This allows features very close to bright sources of light to be seen in great detail [1]. SPHERE clearly revealed how the brilliant light of VY Canis Majoris was lighting up clouds of material surrounding it.

And by using the ZIMPOL mode of SPHERE, the team could not only peer deeper into the heart of this cloud of gas and dust around the star, but they could also see how the starlight was scattered and polarised by the surrounding material. These measurements were key to discovering the elusive properties of the dust.

Wide-field view of the sky around VY Canis Majoris

Careful analysis of the polarisation results revealed these grains of dust to be comparatively large particles, 0.5 micrometres across, which may seem small, but grains of this size are about 50 times larger than the dust normally found in interstellar space.

Throughout their expansion, massive stars shed large amounts of material — every year, VY Canis Majoris sees 30 times the mass of the Earth expelled from its surface in the form of dust and gas. This cloud of material is pushed outwards before the star explodes, at which point some of the dust is destroyed, and the rest cast out into interstellar space. This material is then used, along with the heavier elements created during the supernova explosion, by the next generation of stars, which may make use of the material for planets.

Until now, it had remained mysterious how the material in these giant stars’ upper atmospheres is pushed away into space before the host explodes. The most likely driver has always seemed to be radiation pressure, the force that starlight exerts. As this pressure is very weak, the process relies on large grains of dust, to ensure a broad enough surface area to have an appreciable effect [2].

Zooming in on the red hypergiant star VY Canis Majoris

“Massive stars live short lives,” says lead author of the paper, Peter Scicluna, of the Academia Sinica Institute for Astronomy and Astrophysics, Taiwan. “When they near their final days, they lose a lot of mass. In the past, we could only theorise about how this happened. But now, with the new SPHERE data, we have found large grains of dust around this hypergiant. These are big enough to be pushed away by the star’s intense radiation pressure, which explains the star’s rapid mass loss.”

The large grains of dust observed so close to the star mean that the cloud can effectively scatter the star’s visible light and be pushed by the radiation pressure from the star. The size of the dust grains also means much of it is likely to survive the radiation produced by VY Canis Majoris’ inevitable dramatic demise as a supernova [3]. This dust then contributes to the surrounding interstellar medium, feeding future generations of stars and encouraging them to form planets.


[1] SPHERE/ZIMPOL uses extreme adaptive optics to create diffraction-limited images, which come a lot closer than previous adaptive optics instruments to achieving the theoretical limit of the telescope if there were no atmosphere. Extreme adaptive optics also allows much fainter objects to be seen very close to a bright star.

The images in the new study are also taken in visible light — shorter wavelengths than the near-infrared regime, where most earlier adaptive optics imaging was performed. These two factors result in significantly sharper images than earlier VLT images. Even higher spatial resolution has been achieved with the VLTI, but the interferometer does not create images directly.

[2] The dust particles must be large enough to ensure the starlight can push it, but not so large that it simply sinks. Too small and the starlight would effectively pass through the dust; too large and the dust would be too heavy to push. The dust the team observed about VY Canis Majoris was precisely the right size to be most effectively propelled outwards by the starlight.

[3] The explosion will be soon by astronomical standards, but there is no cause for alarm, as this dramatic event is not likely for hundreds of thousands of years. It will be spectacular as seen from Earth — perhaps as bright as the Moon — but not a hazard to life here.

More information:

This research was presented in a paper entitled “Large dust grains in the wind of VY Canis Majoris”, by P. Scicluna et al., to appear in the journal Astronomy & Astrophysics.

The team is composed of P. Scicluna (Academia Sinica Institute for Astronomy and Astrophysics, Taiwan), R. Siebenmorgen (ESO, Garching, Germany), J. Blommaert (Vrije Universiteit, Brussels, Belgium), M. Kasper (ESO, Garching, Germany), N.V. Voshchinnikov (St. Petersburg University, St. Petersburg, Russia), R. Wesson (ESO, Santiago, Chile) and S. Wolf (Kiel University, Kiel, Germany).

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 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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 a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.


Research paper:

Link to ESOcast about polarimetry:

Photos of the VLT:

SPHERE instrument:

Images, Text, Credits: ESO/IAU and Sky & Telescope/Digitized Sky Survey 2. Acknowledgement: Davide De Martin/Video: ESO/Digitized Sky Survey 2/N. Risinger ( Johan B. Monell.

Best regards,

Loss of Carbon in Martian Atmosphere Explained

NASA - Mars Science Laboratory (MSL) logo.

November 25, 2015

Mars is blanketed by a thin, mostly carbon dioxide atmosphere -- one that is far too thin to keep water from freezing or quickly evaporating. However, geological evidence has led scientists to conclude that ancient Mars was once a warmer, wetter place than it is today. To produce a more temperate climate, several researchers have suggested that the planet was once shrouded in a much thicker carbon dioxide atmosphere. For decades that left the question, "Where did all the carbon go?"

The solar wind stripped away much of Mars' ancient atmosphere and is still removing tons of it every day. But scientists have been puzzled by why they haven't found more carbon -- in the form of carbonate -- captured into Martian rocks. They have also sought to explain the ratio of heavier and lighter carbons in the modern Martian atmosphere.

Image above: This graphic depicts paths by which carbon has been exchanged among Martian interior, surface rocks, polar caps, waters and atmosphere, and also depicts a mechanism by which it is lost from the atmosphere with a strong effect on isotope ratio. Image Credits: Lance Hayashida/Caltech.

Now a team of scientists from the California Institute of Technology and NASA's Jet Propulsion Laboratory, both in Pasadena, offer an explanation of the "missing" carbon, in a paper published today by the journal Nature Communications.

They suggest that 3.8 billion years ago, Mars might have had a moderately dense atmosphere. Such an atmosphere -- with a surface pressure equal to or less than that found on Earth -- could have evolved into the current thin one, not only minus the "missing" carbon problem, but also in a way consistent with the observed ratio of carbon-13 to carbon-12, which differ only by how many neutrons are in each nucleus.

"Our paper shows that transitioning from a moderately dense atmosphere to the current thin one is entirely possible," says Caltech postdoctoral fellow Renyu Hu, the lead author. "It is exciting that what we know about the Martian atmosphere can now be pieced together into a consistent picture of its evolution -- and this does not require a massive undetected carbon reservoir."

When considering how the early Martian atmosphere might have transitioned to its current state, there are two possible mechanisms for the removal of the excess carbon dioxide. Either the carbon dioxide was incorporated into minerals in rocks called carbonates or it was lost to space.

An August 2015 study used data from several Mars-orbiting spacecraft to inventory carbonates, showing there are nowhere near enough in the upper half mile (one kilometer) or the crust to contain the missing carbon from a thick early atmosphere during a time when networks of ancient river channels were active, about 3.8 billion years ago.

The escaped-to-space scenario has also been problematic. Because various processes can change the relative amounts of carbon-13 to carbon-12 isotopes in the atmosphere, "we can use these measurements of the ratio at different points in time as a fingerprint to infer exactly what happened to the Martian atmosphere in the past," says Hu. The first constraint is set by measurements of the ratio in meteorites that contain gases released volcanically from deep inside Mars, providing insight into the starting isotopic ratio of the original Martian atmosphere. The modern ratio comes from measurements by the SAM (Sample Analysis at Mars) instrument on NASA's Curiosity rover.

Mars Science Laboratory (MSL) or Curiosity rover. Image Credits: NASA/JPL-Caltech

One way carbon dioxide escapes to space from Mars' atmosphere is called sputtering, which involves interactions between the solar wind and the upper atmosphere. NASA's MAVEN (Mars Atmosphere and Volatile Evolution) mission has yielded recent results indicating that about a quarter pound (about 100 grams) of particles every second are stripped from today's Martian atmosphere via this process, likely the main driver of atmospheric loss. Sputtering slightly favors loss of carbon-12, compared to carbon-13, but this effect is small. The Curiosity measurement shows that today's Martian atmosphere is far more enriched in carbon-13 -- in proportion to carbon-12 -- than it should be as a result of sputtering alone, so a different process must also be at work.

Hu and his co-authors identify a mechanism that could have significantly contributed to the carbon-13 enrichment. The process begins with ultraviolet (UV) light from the sun striking a molecule of carbon dioxide in the upper atmosphere, splitting it into carbon monoxide and oxygen. Then, UV light hits the carbon monoxide and splits it into carbon and oxygen. Some carbon atoms produced this way have enough energy to escape from the atmosphere, and the new study shows that carbon-12 is far more likely to escape than carbon-13.

Modeling the long-term effects of this "ultraviolet photodissociation" mechanism, the researchers found that a small amount of escape by this process leaves a large fingerprint in the carbon isotopic ratio. That, in turn, allowed them to calculate that the atmosphere 3.8 billion years ago might have had a surface pressure a bit less thick than Earth's atmosphere today.

"This solves a long-standing paradox," said Bethany Ehlmann of Caltech and JPL, a co-author of both today's publication and the August one about carbonates. "The supposed very thick atmosphere seemed to imply that you needed this big surface carbon reservoir, but the efficiency of the UV photodissociation process means that there actually is no paradox. You can use normal loss processes as we understand them, with detected amounts of carbonate, and find an evolutionary scenario for Mars that makes sense."

Related articles:

NASA Mission Reveals Speed of Solar Wind Stripping Martian Atmosphere:

What Happened to Early Mars' Atmosphere? New Study Eliminates One Theory:

JPL manages Curiosity for NASA's Science Mission Directorate, Washington, as part of NASA's progress toward a human mission to Mars. Caltech manages JPL for NASA. For more information about Curiosity, visit:

You can follow the mission on Facebook and Twitter at:

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/Guy Webster/California Institute of Technology/Deborah Williams-Hedges.


Strange Star Likely Swarmed by Comets

NASA - Spitzer Space Telescope logo / NASA - Kepler Mission patch.

November 25, 2015

Image above: This illustration shows a star behind a shattered comet. Image credit: NASA/JPL-Caltech.

A star called KIC 8462852 has been in the news recently for unexplained and bizarre behavior. NASA's Kepler mission had monitored the star for four years, observing two unusual incidents, in 2011 and 2013, when the star's light dimmed in dramatic, never-before-seen ways. Something had passed in front of the star and blocked its light, but what?

Scientists first reported the findings in September, suggesting a family of comets as the most likely explanation. Other cited causes included fragments of planets and asteroids.

Artist's view of Spitzer Space Telescope. Image Credit: NASA

A new study using data from NASA's Spitzer Space Telescope addresses the mystery, finding more evidence for the scenario involving a swarm of comets. The study, led by Massimo Marengo of Iowa State University, Ames, is accepted for publication in the Astrophysical Journal Letters.

One way to learn more about the star is to study it in infrared light. Kepler had observed it in visible light. If a planetary impact, or a collision amongst asteroids, were behind the mystery of KIC 8462852, then there should be an excess of infrared light around the star. Dusty, ground-up bits of rock would be at the right temperature to glow at infrared wavelengths.

At first, researchers tried to look for infrared light using NASA's Wide-Field Infrared Survey Explorer, or WISE, and found none. But those observations were taken in 2010, before the strange events seen by Kepler -- and before any collisions would have kicked up dust.

Artist's view of Kepler Space Telescope. Image Credit: NASA

To search for infrared light that might have been generated after the oddball events, researchers turned to Spitzer, which, like WISE, also detects infrared light. Spitzer just happened to observe KIC 8462852 more recently in 2015.

"Spitzer has observed all of the hundreds of thousands of stars where Kepler hunted for planets, in the hope of finding infrared emission from circumstellar dust," said Michael Werner, the Spitzer project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and the lead investigator of that particular Spitzer/Kepler observing program.

But, like WISE, Spitzer did not find any significant excess of infrared light from warm dust. That makes theories of rocky smashups very unlikely, and favors the idea that cold comets are responsible. It's possible that a family of comets is traveling on a very long, eccentric orbit around the star. At the head of the pack would be a very large comet, which would have blocked the star's light in 2011, as noted by Kepler. Later, in 2013, the rest of the comet family, a band of varied fragments lagging behind, would have passed in front of the star and again blocked its light.

By the time Spitzer observed the star in 2015, those comets would be farther away, having continued on their long journey around the star. They would not leave any infrared signatures that could be detected.

According to Marengo, more observations are needed to help settle the case of KIC 8462852.

"This is a very strange star," he said. "It reminds me of when we first discovered pulsars. They were emitting odd signals nobody had ever seen before, and the first one discovered was named LGM-1 after 'Little Green Men.'"

In the end, the LGM-1 signals turned out to be a natural phenomenon.

"We may not know yet what's going on around this star," Marengo observed. "But that's what makes it so interesting."

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. JPL managed Kepler mission development. Ball Aerospace & Technologies Corp. operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech.

Caltech manages JPL for NASA.

For more information about Kepler and Spitzer, respectively, visit:

Images (mentioned), Text, Credits: NASA/JPL/Whitney Clavin/Ames Research Center/Michele Johnson.


mardi 24 novembre 2015

Blue Origin Makes Historic Rocket Landing

Blue Origin logo.

Nov 24, 2015

Image above: As the sun rises over the launch site, we’ll complete final pre-launch checks and clear you for flight. Image Credit: Blue Origin.

Blue Origin today announced that its New Shepard space vehicle successfully flew to space, reaching its planned test altitude of 329,839 feet (100.5 kilometers) before executing a historic landing back at the launch site in West Texas. To receive updates on Blue Origin’s continuing progress and early access to ticketing information, sign up at

Image above: The combined capsule and booster will launch vertically from the launch pad. Image Credit: Blue Origin.

“Now safely tucked away at our launch site in West Texas is the rarest of beasts—a used rocket,” said Jeff Bezos, founder of Blue Origin. “Blue Origin’s reusable New Shepard space vehicle flew a flawless mission—soaring to 329,839 feet and then returning through 119-mph high-altitude crosswinds to make a gentle, controlled landing just four and a half feet from the center of the pad. Full reuse is a game changer, and we can’t wait to fuel up and fly again.”

Blue Origin Historic Rocket Landing

Named in honor of the first American in space, Alan Shepard, the New Shepard vertical takeoff and vertical landing vehicle will carry six astronauts to altitudes beyond 100 kilometers, the internationally-recognized boundary of space. Blue Origin astronauts will experience the thrill of launch atop a rocket, the freedom of weightlessness, and views through the largest windows to ever fly in space. An animation of the Blue Origin astronaut experience can be found at Astronaut flights will begin following completion of a methodical flight test program.

Blue Origin capsule landing. Image Credit: Blue Origin

Details on the Reusable New Shepard Space Vehicle

The New Shepard space vehicle is fully reusable and operated from Blue Origin’s West Texas launch site. The vehicle is comprised of two elements—a crew capsule in which the astronauts ride and a rocket booster powered by a single American-made BE-3 liquid hydrogen, liquid oxygen engine. At liftoff, the BE-3 delivers 110,000 pounds of thrust. During ascent, astronauts experience 3x the force of gravity as the spacecraft accelerates through the atmosphere.

Blue Origin Makes Historic Rocket Landing. Image Credit: Blue Origin

Following powered flight, the crew capsule separates from the booster and coasts into space, providing several minutes of weightlessness. As the crew capsule descends, it reenters the atmosphere with astronauts experiencing about 5x the force of gravity before deploying three main parachutes for landing. Meanwhile, the booster descends under guided flight to the landing pad. Just prior to landing, the booster re-ignites its BE-3 engine which slows the vehicle to 4.4 mph for a gentle, powered vertical landing, enabling vehicle reuse.

About Blue Origin

Blue Origin, LLC (Blue Origin) is a private company developing vehicles and technologies to enable commercial human space transportation. Blue Origin has a long-term vision of greatly increasing the number of people that fly into space so that we humans can better continue exploring the solar system. For more information and a list of job openings, please visit us at

Images (mentioned), Video, Text, Credit: Blue Origin.

Best regards,

NASA Study Suggests Carbon Content of Temperate Forests Overestimated

NASA -  Goddard Space Flight Center logo / ISS - International Space Station patch.

Nov. 24, 2015

Digital measurements of millions of trees indicate that previous studies likely overestimate the amount of carbon stored by temperate U.S. forests, according to a new NASA study.

The findings could help scientists better understand the impact that trees have on the amount of carbon in the atmosphere. Although it is a well-established fact that trees absorb carbon and store it long-term, researchers are unsure how much is stored in global forests.

“Estimates of the carbon content of living trees typically rely on a method that is based on cutting down trees,” said Laura Duncanson, a postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It takes a lot of effort to cut down trees, particularly the biggest ones, so this just isn’t practical to do in large numbers.”

Image above: The landscape shown here is not a photograph but a 3-D visualization obtained using lidar and aerial imagery. Lidar is a remote sensing technique that can be used to digitally measure the heights and crown dimensions of trees, not just for a small sample but for every tree across a landscape. Image Credits: NASA/University of Maryland.

Because of this limitation, field studies aim to strategically sample trees. When looking at U.S. forests, for example, on average about 30 trees of each species would be cut down and measured. Researchers would then use basic mathematical models to scale up those measurements to many thousands, or even millions, of trees, resulting in an estimate of the biomass – the amount of carbon stored – for an entire forest.

In the paper, published on Nov. 24 in Scientific Reports, Duncanson and her co-investigators, Ralph Dubayah and Oliver Rourke, both from the University of Maryland, College Park, found that this widely used method tends to overestimate the height of large trees, leading to biomass figures that are much too high for temperate forests. This overestimation occurs because of a sampling bias: many more young, smaller trees get selected for analysis than older, larger trees. Because the mathematical models that predict tree biomass are mostly based on the smaller trees, the resulting models do not make accurate predictions for the largest trees.

Instead of sampling trees by cutting them down, the new study used lidar, a laser-based technique that can analyze whole swaths of forest from above. The data were provided primarily by Goddard’s Lidar, Hyperspectral and Thermal instrument, known as G-LiHT. This portable lidar can be flown on an aircraft to provide fine-scale observations with a resolution of less than 3.3 feet (1 meter) over large areas.

“One of the innovations of this work is our use of lidar remote sensing to measure potentially millions of trees,” said Dubayah, a professor of geographical sciences. “This is a dramatically different approach when you consider how few trees are normally used to develop these relationships.”

Image above: The Global Ecosystem Dynamics Investigation lidar will reveal the 3-D architecture of forests, as depicted in this artist's concept. Image Credits: NASA/GSFC.

From the lidar data, the researchers extracted digital measurements of the height and crown radius – the average horizontal spread of the limbs – for every tree selected. The team studied six U.S. forests, digitally measuring 10,000 to more than a million trees at each site. These measurements were used to develop new mathematical models to estimate the biomass of the forests.

Next, the researchers reran the models using only a sampling of the measurements – starting with tens of trees and going up to a few thousand. Including more trees led to better estimates, primarily because more large trees were accounted for. The team determined that when the small sample sizes typical of the conventional approach were used, the figures overestimated the inferred biomass of temperate forests by 70 percent, on average.

The bias that results from sampling small numbers of trees has been well studied in tropical forests. Even so, the researchers were surprised to discover the magnitude of the issue for temperate forests.

Image above: location of the Global Ecosystem Dynamics Investigation Lidar (GEDI) on ISS. Image Credit: NASA.

“Our findings underscore the importance of sampling more trees,” said Duncanson. “When you include more trees, and especially more big trees, you get a much better idea of how much carbon is being stored.”

New lidar instruments are being developed to help study the biomass of forests, including NASA’s Global Ecosystem Dynamics Investigation, or GEDI, an instrument led by Dubayah and being built at Goddard. GEDI will be the first instrument to systematically characterize forest canopies from space.

“GEDI will help fill in this missing piece of the carbon puzzle by measuring the vertical structure of the forest, which is information we cannot get with sufficient accuracy any other way,” said Dubayah.

Related links:

International Space Station (ISS):

Missions - GEDI - NASA Science - Science@NASA:

Global Ecosystem Dynamics Investigation Lidar (GEDI):

NASA's Goddard Space Flight Center:

NASA's Goddard Space Flight Center/Elizabeth Zubritsky/Karl Hille/University of Maryland/Laura Ours.

NEOWISE Identifies Greenhouse Gases in Comets

NASA - NEOWISE Mission logo.

November 24, 2015

Image above: An expanded view of comet C/2006 W3 (Christensen) is shown here. The WISE spacecraft observed this comet on April 20th, 2010 as it traveled through the constellation Sagittarius. Image Credits: NASA/JPL-Caltech.

After its launch in 2009, NASA's NEOWISE spacecraft observed 163 comets during the WISE/NEOWISE prime mission. This sample from the space telescope represents the largest infrared survey of comets to date. Data from the survey are giving new insights into the dust, comet nucleus sizes, and production rates for difficult-to-observe gases like carbon dioxide and carbon monoxide. Results of the NEOWISE census of comets were recently published in the Astrophysical Journal.

Carbon monoxide (CO) and carbon dioxide (CO2) are common molecules found in the environment of the early solar system, and in comets. In most circumstances, water-ice sublimation likely drives the activity in comets when they come nearest to the sun, but at larger distances and colder temperatures, other common molecules like CO and CO2 may be the main drivers. Spaceborne carbon dioxide and carbon monoxide are difficult to directly detect from the ground because their abundance in Earth's own atmosphere obscures the signal. The NEOWISE spacecraft soars high above Earth's atmosphere, making these measurements of a comet's gas emissions possible.

"This is the first time we've seen such large statistical evidence of carbon monoxide taking over as a comet's gas of choice when they are farther out from the sun," said James Bauer, deputy principal investigator of the NEOWISE mission from NASA's Jet Propulsion Laboratory in Pasadena, California, and author of a paper on the subject. "By emitting what is likely mostly carbon monoxide beyond four astronomical units (4 times the Earth-Sun distance; about 370 million miles, 600 million kilometers) it shows us that comets may have stored most of the gases when they formed, and secured them over billions of years. Most of the comets that we observed as active beyond 4 AU are long-period comets, comets with orbital periods greater than 200 years that spend most of their time beyond Neptune's orbit."

NASA's NEOWISE spacecraft.  Image Credits: NASA/JPL-Caltech

While the amount of carbon monoxide and dioxide increases relative to ejected dust as a comet gets closer to the sun, the percentage of these two gases, when compared to other volatile gases, decreases.

"As they get closer to the sun, these comets seem to produce a prodigious amount of carbon dioxide," said Bauer. "Your average comet sampled by NEOWISE would expel enough carbon dioxide to provide the bubble power for thousands of cans of soda per second."

The pre-print version of this paper is available at:

The NEOWISE mission hunts for near-Earth objects using the Wide-field Infrared Survey Explorer (WISE) spacecraft. Funded by NASA's Planetary Science division, the NEOWISE project uses images taken by the spacecraft to look for asteroids and comets, providing a rich source of measurements of solar system objects at infrared wavelengths. These measurements include emission lines that are difficult or impossible to detect directly from the ground.

More information about the NEOWISE mission is at:

Images (mentioned), Text, Credits: NASA/JPL/DC Agle.


H-IIA Rocket Successfully Launches Telstar 12 VANTAGE Satellite

JAXA - Japan Aerospace Exploration Agency logo / JAXA - H-IIA UPGRADE logo.

November 24, 2015

H-IIA Rocket Successfully Launches Telstar 12 VANTAGE Satellite

The H-IIA launch vehicle F29 lifted off from the Yoshinobu launch pad at the Tanegashima Space Center today at 15:50 local time (6:50 GMT and 01:50 EST). The launch vehicle flew as planned and, at about 4 hours and 27 minutes after liftoff, the separation of the Telstar 12 VANTAGE satellite was confirmed. H-IIA F29 incorporates the outcome of the H-IIA Upgrade. The upgrade relates to improvements in the launch vehicle's upper stage and MHI has been implementing these improvements with strong support and oversight from the Japan Aerospace Exploration Agency (JAXA).

H-IIA Rocket Launches Telstar 12 VANTAGE Satellite

The H-IIA UPGRADE brought unique capabilities to the H-IIA launch vehicle. The upgrade enables the H-IIA to perform a long coast flight, and allows the second stage engine to ignite for the third time at the apogee. With these new capabilities, the H-IIA was able to inject the Telstar 12 VANTAGE closer to geostationary orbit than conventional geostationary transfer orbit.


Telstar 12 VANTAGE replaces and expands on Telesat's Telstar 12 satellite. Telstar 12 has long been valued by the satellite user community for its ability to seamlessly connect the Americas to Europe and the Middle East from 15 West, one of the few orbital locations that enables such coverage. With Telstar 12 VANTAGE, broadband customers in mobility, government, energy and enterprise markets will now have even greater service options between EMEA and the Americas along with powerful new beams over Brazil, Sub-Saharan Africa, the South Atlantic, the Mediterranean and North Sea.

Telstar 12 VANTAGE Satellite

MHI and JAXA would like to express our profound appreciation for the cooperation and support of all related personnel and organizations that helped contribute to the successful launch of the H-IIA F29.

At the time of the launch, the weather was fine, a wind speed was 8.6 meters/second from the north-east and the temperature was 22.0 degrees Celsius.


MHI Launch Services -H-IIA/H-IIB Launch Vehicle- :

H-IIA Launch Vehicle:

For more information about Japan Aerospace Exploration Agency (JAXA), visit:

Images, Video, Text, Credits: Japan Aerospace Exploration Agency (JAXA)/National Research and Development Agency/Mitsubishi Heavy Industries, Ltd./Airbus Defence and Space/Akameeba.

Best regards,