Sentinel-3A Earth Colour Data Released

ESA - Sentinel-3 Mission logo.

20 October 2016

Today, the Copernicus Sentinel-3A satellite has taken another step towards being fully ‘operational’ as the first data from its Ocean and Land Colour Instrument are made available to monitor the health of our planet.

Following its launch in February, the satellite and instruments have been thoroughly tested and fine-tuned – leading to this important milestone.

Carrying a suite of instruments, Sentinel-3A is arguably the most complex of all the Copernicus Sentinels.

 Greenland changing ice

It has been designed to measure Earth’s oceans, land, ice and atmosphere to monitor large-scale global dynamics and to provide critical near-realtime information for numerous ocean, land and weather applications.

The Sentinel-3 validation team, a group of expert users, has been receiving sample products since May. Their feedback is essential to both ESA and Eumetsat to ensure the data are of the highest quality, as is needed for the myriad of operational applications that the mission will serve.

Sentinel-3

At the ‘end of commissioning’ review in July, it was noted that a couple of points had to be addressed before the first data were officially released to the public.

Susanne Mecklenburg, ESA’s Sentinel-3 mission manager, said, “It is imperative that these first-level data are the best quality possible so we are being extremely careful. It is now very gratifying to see data from the satellite’s Ocean and Land Colour Instrument being released to users worldwide.

“Data from the other two instruments – the Sea and Land Surface Temperature Radiometer and Radar Altimeter – will be made available in November and December, respectively.”

Wide and detailed views

Offering new eyes on Earth, the Ocean and Land Colour Instrument will monitor the global oceans, and inland waters, including phytoplankton, water quality, harmful algal blooms, sediment transport in coastal areas, El Niño and La Niña events, and climate change.

It will also support observations of vegetation and crop conditions, as well as provide estimates of atmospheric aerosol and clouds – all of which bring significant benefits to society through more informed decision-making.

While the operations of the Sentinel-3A satellite are carried out by Eumetsat, the mission is managed jointly by ESA and Eumetsat.

ESA is responsible for the land data products and Eumetsat for the marine products – all of which are made available for application through Copernicus services.

Mediterranean view

Hilary Wilson, Eumetsat’s Sentinel-3 project manager, said, “The release of Sentinel-3A’s first operational data is the culmination of a lot of hard work by ESA, Eumetsat and the expert user teams.

“It represents an important milestone for the Copernicus Marine Environment Monitoring Service and also for the wider marine monitoring community.

“Routine operations of the satellite have been proceeding smoothly since Eumetsat took over this responsibility in July and we are now focusing on bringing the remaining marine products to this community.”

Related links:

Copernicus Marine Environment Monitoring Service: http://copernicus.eu/main/marine-monitoring

Copernicus Land Monitoring Service: http://copernicus.eu/main/land-monitoring

Eumetsat–Sentinel-3: http://www.eumetsat.int/website/home/News/DAT_3247520.html

Sentinel data access & technical information: https://sentinels.copernicus.eu/web/sentinel/home

Animation: contains modified Copernicus Sentinel data (2016), processed by ESA/Images: contains modified Copernicus Sentinel data (2016) processed by Eumetsat/ATG medialab/Text, Credit: European Space Agency (ESA).

Best regards, Orbiter.ch

Schiaparelli descent data: decoding underway

ESA - ExoMars Mission logo.

20 October 2016

Essential data from the ExoMars Schiaparelli lander sent to its mothership Trace Gas Orbiter during the module’s descent to the Red Planet’s surface yesterday has been downlinked to Earth and is currently being analysed by experts.

Early indications from both the radio signals captured by the Giant Metrewave Radio Telescope (GMRT), an experimental telescope array located near Pune, India, and from orbit by ESA’s Mars Express, suggested the module had successfully completed most steps of its 6-minute descent through the martian atmosphere. This included the deceleration through the atmosphere, and the parachute and heat shield deployment, for example.

But the signals recorded by both Pune and Mars Express stopped shortly before the module was expected to touchdown on the surface. Discrepancies between the two data sets are being analysed by experts at ESA’s space operations centre in Darmstadt, Germany.

Schiaparelli with parachute deployed

The detailed telemetry recorded by the Trace Gas Orbiter was needed to better understand the situation. At the same time as Schiaparelli’s descent, the orbiter was performing a crucial ‘Mars Orbit Insertion’ manoeuvre – which it completed successfully. These important data were recorded from Schiaparelli and beamed back to Earth in the early hours of Thursday morning.

The data have been partially analysed and confirm that the entry and descent stages occurred as expected, with events diverging from what was expected after the ejection of the back heat shield and parachute. This ejection itself appears to have occurred earlier than expected, but analysis is not yet complete.

The thrusters were confirmed to have been briefly activated although it seems likely that they switched off sooner than expected, at an altitude that is still to be determined.

“Following yesterday’s events we have an impressive orbiter around Mars ready for science and for relay support for the ExoMars rover mission in 2020,” said Jan Wörner, ESA’s Director General.

ExoMars From separation to landing

“Schiaparelli’s primary role was to test European landing technologies. Recording the data during the descent was part of that, and it is important we can learn what happened, in order to prepare for the future.”

“In terms of the Schiaparelli test module, we have data coming back that allow us to fully understand the steps that did occur, and why the soft landing did not occur,” said David Parker, ESA’s Director of Human Spaceflight and Robotic Exploration.

“From the engineering standpoint, it’s what we want from a test, and we have extremely valuable data to work with. We will have an enquiry board to dig deeper into the data and we cannot speculate further at this time.”

Related links:

Robotic exploration of Mars: http://exploration.esa.int/

Roscosmos: http://en.federalspace.ru/

ExoMars at IKI: http://exomars.cosmos.ru/

Thales Alenia Space: https://www.thalesgroup.com/en/worldwide/space/space

NASA In 2016 ExoMars orbiter (Electra radio): http://mars.nasa.gov/programmissions/missions/future/exomarsorbiter2016/

Where on Mars?: http://whereonmars.co/

More about...

ExoMars Factsheet: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_Factsheet

ExoMars frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/ExoMars/ExoMars_frequently_asked_questions

ExoMars brochure: http://www.esa.int/About_Us/ESA_Publications/ESA_Publications_Brochures/ESA_BR-327_EXOMARS_2016

Image, Video, Text, Credits: ESA/ATG medialab.

Best regards, Orbiter.ch

NASA’s MAVEN Mission Observes Ups and Downs of Water Escape from Mars

NASA - MAVEN Mission logo.

Oct. 19, 2016

After investigating the upper atmosphere of the Red Planet for a full Martian year, NASA’s MAVEN mission has determined that the escaping water does not always go gently into space.

Sophisticated measurements made by a suite of instruments on the Mars Atmosphere and Volatile Evolution, or MAVEN, spacecraft revealed the ups and downs of hydrogen escape – and therefore water loss. The escape rate peaked when Mars was at its closest point to the sun and dropped off when the planet was farthest from the sun. The rate of loss varied dramatically overall, with 10 times more hydrogen escaping at the maximum.

“MAVEN is giving us unprecedented detail about hydrogen escape from the upper atmosphere of Mars, and this is crucial for helping us figure out the total amount of water lost over billions of years,” said Ali Rahmati, a MAVEN team member at the University of California at Berkeley who analyzed data from two of the spacecraft’s instruments.

Hydrogen in Mars’ upper atmosphere comes from water vapor in the lower atmosphere. An atmospheric water molecule can be broken apart by sunlight, releasing the two hydrogen atoms from the oxygen atom that they had been bound to. Several processes at work in Mars’ upper atmosphere may then act on the hydrogen, leading to its escape.

Image above: This image shows atomic hydrogen scattering sunlight in the upper atmosphere of Mars, as seen by the Imaging Ultraviolet Spectrograph on NASA’s Mars Atmosphere and Volatile Evolution mission. About 400,000 observations, taken over the course of four days shortly after the spacecraft entered orbit around Mars, were used to create the image. Hydrogen is produced by the breakdown of water, which was once abundant on Mars' surface. Because hydrogen has low atomic mass and is weakly bound by gravity, it extends far from the planet (the darkened circle) and can readily escape. Image Credits: NASA/Goddard/University of Colorado.

This loss had long been assumed to be more-or-less constant, like a slow leak in a tire. But previous observations made using NASA’s Hubble Space Telescope and ESA’s Mars Express orbiter found unexpected fluctuations. Only a handful of these measurements have been made so far, and most were essentially snapshots, taken months or years apart. MAVEN has been tracking the hydrogen escape without interruption over the course of a Martian year, which lasts nearly two Earth years.

“Now that we know such large changes occur, we think of hydrogen escape from Mars less as a slow and steady leak and more as an episodic flow – rising and falling with season and perhaps punctuated by strong bursts,” said Michael Chaffin, a scientist at the University of Colorado at Boulder who is on the Imaging Ultraviolet Spectrograph (IUVS) team. Chaffin is presenting some IUVS results on Oct. 19 at the joint meeting of the Division for Planetary Sciences and the European Planetary Science Congress in Pasadena, California.

In the most detailed observations of hydrogen loss to date, four of MAVEN’s instruments detected the factor-of-10 change in the rate of escape. Changes in the density of hydrogen in the upper atmosphere were inferred from the flux of hydrogen ions – electrically charged hydrogen atoms – measured by the Solar Wind Ion Analyzer and by the Suprathermal and Thermal Ion Composition instrument. IUVS observed a drop in the amount of sunlight scattered by hydrogen in the upper atmosphere. MAVEN’s magnetometer found a decrease in the occurrence of electromagnetic waves excited by hydrogen ions, indicating a decrease in the amount of hydrogen present.

By investigating hydrogen escape in multiple ways, the MAVEN team will be able to work out which factors drive the escape. Scientists already know that Mars’ elliptical orbit causes the intensity of the sunlight reaching Mars to vary by 40 percent during a Martian year. There also is a seasonal effect that controls how much water vapor is present in the lower atmosphere, as well as variations in how much water makes it into the upper atmosphere. The 11-year cycle of the sun’s activity is another likely factor.

Mars Atmosphere and Volatile Evolution mission or MAVEN spacecraft. Image Credit: NASA

“In addition, when Mars is closest to the sun, the atmosphere becomes turbulent, resulting in global dust storms and other activity. This could allow the water in the lower atmosphere to rise to very high altitudes, providing an intermittent source of hydrogen that can then escape,” said John Clarke, a Boston University scientist on the IUVS team. Clarke will present IUVS measurements of hydrogen and deuterium – a form of hydrogen that contains a neutron and is heavier – on Oct. 19 at the planetary conference.

By making observations for a second Mars year and during different parts of the solar cycle, the scientists will be better able to distinguish among these effects. MAVEN is continuing these observations in its extended mission, which has been approved until at least September 2018.

“MAVEN’s findings reveal what is happening in Mars’ atmosphere now, but over time this type of loss contributed to the global change from a wetter environment to the dry planet we see today,” said Rahmati.

MAVEN’s principal investigator is based at the University of Colorado’s Laboratory for Atmospheric and Space Physics, Boulder. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN project and provided two science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. The University of California at Berkeley’s Space Sciences Laboratory also provided four science instruments for the mission. NASA’s Jet Propulsion Laboratory in Pasadena, California, provides navigation and Deep Space Network support, as well as the Electra telecommunications relay hardware and operations.

For more information about MAVEN (Mars Atmosphere and Volatile Evolution), visit: https://www.nasa.gov/mission_pages/maven/main/index.html

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center, written by Elizabeth Zubritsky/Karl Hille.

Greetings, Orbiter.ch

Juno Spacecraft in Safe Mode for Latest Jupiter Flyby

NASA - JUNO Mission logo.

Oct. 19, 2016

Scientists Intrigued by Data from First Flyby - Mission Status Report

Image above: This artist's rendering shows NASA's Juno spacecraft making one of its close passes over Jupiter. Image Credit: NASA.

NASA’s Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT (Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance monitor induced a reboot of the spacecraft’s onboard computer. The spacecraft acted as expected during the transition into safe mode, restarted successfully and is healthy.  High-rate data has been restored, and the spacecraft is conducting flight software diagnostics. All instruments are off, and the planned science data collection for today’s close flyby of Jupiter (perijove 2), did not occur.

“At the time safe mode was entered, the spacecraft was more than 13 hours from its closest approach to Jupiter,” said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a ways from the planet’s more intense radiation belts and magnetic fields. The spacecraft is healthy and we are working our standard recovery procedure.”

The spacecraft is designed to enter safe mode if its onboard computer perceives conditions are not as expected. In this case, the safe mode turned off instruments and a few non-critical spacecraft components, and it confirmed the spacecraft was pointed toward the sun to ensure the solar arrays received power.

Mission managers are continuing to study an unrelated issue with the performance of a pair of valves that are part of the spacecraft’s propulsion system. Last week the decision was made to postpone a burn of the spacecraft’s main engine that would have reduced Juno’s orbital period from 53.4 to 14 days.

Image above: This composite image depicts Jupiter’s cloud formations as seen through the eyes of Juno’s Microwave Radiometer (MWR) instrument as compared to the top layer, a Cassini Imaging Science Subsystem image of the planet. The MWR can see a couple of hundred miles (kilometers) into Jupiter’s atmosphere with its largest antenna. The belts and bands visible on the surface are also visible in modified form in each layer below. Image Credits: NASA/JPL-Caltech/SwRI/GSFC.

The next close flyby is scheduled on Dec. 11, with all science instruments on.

The Juno science team continues to analyze returns from the first close flyby on Aug. 27. Revelations from that flyby include that Jupiter’s magnetic fields and aurora are bigger and more powerful than originally thought. Juno’s Microwave Radiometer instrument (MWR) also provided data that give mission scientists their first glimpse below the planet’s swirling cloud deck. The radiometer instrument can peer about 215 to 250 miles (350 to 400 kilometers) below Jupiter’s clouds.

“With the MWR data, it is as if we took an onion and began to peel the layers off to see the structure and processes going on below,” said Bolton. “We are seeing that those beautiful belts and bands of orange and white we see at Jupiter’s cloud tops extend in some version as far down as our instruments can see, but seem to change with each layer.”

The JunoCam public outreach camera also was operating during the Aug. 27 flyby. The raw images from that flyby (and all future flybys) were made available on the JunoCam website  (http://www.missionjuno.swri.edu/junocam) for the public to not only peruse but to process into final image products. JunoCam is the first outreach camera to venture beyond the asteroid belt.

Image above: A smiley face can be seen in this image of Jupiter created by a citizen scientist (Randy Ahn) using data from Juno’s JunoCam instrument. In JunoCam’s view, Jupiter is only half-lit, so Ahn copied and flipped the half-smile to make a full smile out of Jupiter’s swirling atmosphere. JunoCam’s raw images are available at http://www.missionjuno.swri.edu/junocam for the public to peruse and process into image products. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Randy Ahn.

“JunoCam has a small operations team and no image processing team, so we took a leap of faith that the public would step up and help us generate images of Jupiter from the raw data,” said Candy Hansen, JunoCam imaging scientist from the Planetary Science Institute in Tucson, Arizona. “All sorts of people are coming to the JunoCam site and providing their own aesthetic. We have volunteers from all over the world, and they are doing beautiful work. So far all our expectations for JunoCam have not only been met but are being exceeded, and we’re just getting started.”

The final image products include straightforward images of the solar system’s largest world, but also some with a certain artistic license, including a variation on Vincent Van Gogh’s Starry Night painting and even a “smiley face” made from an image of Jupiter’s south pole. These amateur-generated JunoCam images are not only being used to help interest the media and public in this mission to the most massive planet in the solar system, but are engaging Juno’s science team as well.

Image above: This image of the sunlit part of Jupiter and its swirling atmosphere was created by a citizen scientist (Alex Mai) using data from Juno’s JunoCam instrument. JunoCam’s raw images are available at http://www.missionjuno.swri.edu/junocam for the public to peruse and process into image products. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Alex Mai.

“The amateurs are giving us a different perspective on how to process images,” said Hansen. “They are experimenting with different color enhancements, different highlights or annotations than we would normally expect.  They are identifying storms tracked from Earth to connect our images to the historical record. This is citizen science at its best.”

The Juno spacecraft launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived at Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

Juno's name comes from Roman mythology. The mythical god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife -- the goddess Juno -- was able to peer through the clouds and reveal Jupiter's true nature.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena, California, manages JPL for NASA.

More information on the Juno mission is available at: http://www.nasa.gov/juno

The public can follow the mission on Facebook and Twitter at: http://www.facebook.com/NASAJuno and http://www.twitter.com/NASAJuno

Images and information on how members of the public can participate in JunoCam’s mission, can be found at:  http://www.missionjuno.swri.edu/junocam

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/DC Agle.

Greetings, Orbiter.ch

Mysterious Cosmic Objects Erupting in X-rays Discovered

NASA - Chandra X-ray Observatory patch.

Oct. 19, 2016

Astronomers have found a pair of extraordinary cosmic objects that dramatically burst in X-rays. This discovery, obtained with NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton observatory, may represent a new class of explosive events found in space.

The mysterious X-ray sources flare up and become about a hundred times brighter in less than a minute, before returning to original X-ray levels after about an hour. At their peak, these objects qualify as ultraluminous X-ray sources (ULXs) that give off hundreds to thousands of times more X-rays than typical binary systems where a star is orbiting a black hole or neutron star.

Animation above: Animation of flaring X-ray source in Galaxy NGC 5128. Animation Credits: NASA/CXC/UA/J.Irwin et al.

“We’ve never seen anything like this,” said Jimmy Irwin of the University of Alabama, who led the study that appears in the latest issue of the journal Nature. “Astronomers have seen many different objects that flare up, but these may be examples of an entirely new phenomenon.”

While magnetars – young neutron stars with powerful magnetic fields – have been known to produce bright and rapid flares in X-rays, these newly discovered objects are different in key ways.

First, magnetars only take a few seconds to tens of seconds to decline in X-rays after a flare. Secondly, these new flaring objects are found in populations of old stars in elliptical galaxies, which are spherical or egg-shaped galaxies that are composed mostly of older stars.

This makes it unlikely that these new flaring objects are young, astronomically speaking, like magnetars are thought to be. Also, these objects are brighter in X-rays during their “calm” periods.

“These flares are extraordinary,” said Peter Maksym, a co-author from the Harvard-Smithsonian Center for Astrophysics. “For a brief period, one of the sources became one of the brightest ULX to ever be seen in an elliptical galaxy.”

Image above: This image shows the location in galaxy NGC 5128 of a remarkable source that dramatically flares in X-rays unlike any ever seen. Image Credits: NASA/CXC/UA/J.Irwin et al.

When they are not flaring, these sources appear to be normal binary systems where a black hole or neutron star is pulling material from a companion star similar to the Sun. This indicates that the flares do not significantly disrupt the binary system.

While the nature of these flares is unknown, the team has begun to search for answers. One idea is that the flares represent episodes when matter being pulled away from a companion star falls rapidly onto a black hole or neutron star. This could happen when the companion makes its closest approach to the compact object in an eccentric orbit. Another explanation could involve matter falling onto an intermediate-mass black hole, with a mass of about 800 times that of the Sun for one source and 80 times that of the Sun for the other.

“Now that we've discovered these flaring objects, observational astronomers and theorists alike are going to be working hard to figure out what’s happening,” said co-author Gregory Sivakoff of the University of Alberta.

Chandra X-ray Observatory spacecraft. Image Credits: NASA/CXC

One of the sources, located near and presumably associated with the galaxy NGC 4636 at a distance of 47 million light years, was observed with Chandra to flare once. Five flares were detected from the other source, which is located near the galaxy NGC 5128 at a distance of 14 million light years. Four of these flares were seen with Chandra and one with XMM-Newton.

The team looked at the X-ray variation of several thousand X-ray sources in Chandra observations of 70 nearby galaxies. Although several examples of flaring X-ray sources were found, none exhibited the behavior of the giant rapid flares reported here.

NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2016/ngc5128/

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Lee Mohon/Marshall Space Flight Center/Molly Porter/Chandra X-ray Center/Megan Watzke.

Greetings, Orbiter.ch

CERN - n_TOF plays hide-and-seek with cosmological lithium

CERN - European Organization for Nuclear Research logo.

19 October 2016

Image above: Nova Centauri 2013, the brightest star in the centre of the picture, is the first nova star (explosion of a star) in which evidence of lithium has been found in the ejected material. (Image: ESO).

An experiment at the n_TOF facility at CERN filled in a missing piece of the  cosmological lithium problem puzzle. The n_TOF collaboration published a study providing a precise new measurement of one of the processes involved in the cosmic production of lithium.

The observed quantity of this element is indeed much smaller than that predicted by theory. The theory of the production of nuclei during the early phases of the universe – known as Big Bang Nucleosynthesis – states that, right after the Big Bang, all the lightest and most abundant elements of the universe (hydrogen, helium and lithium) were formed. But, while observations and theory are perfectly aligned as regards hydrogen and helium, the amount of lithium that we actually observe is about three times smaller than that deduced by our theoretical predictions. This discrepancy is known as the cosmological lithium problem.

One explanation could be linked to the transformation of an unstable isotope of beryllium – beryllium-7 – into lithium. The production and destruction of beryllium-7 essentially regulate, in turn, the abundance of cosmological lithium: the more beryllium-7, the more lithium there is, but if beryllium somehow gets destroyed, the amount of lithium consequently decreases. Therefore, a possible explanation for the higher theoretical value could be an underestimation of the destruction of primordial beryllium-7, in particular in reactions with neutrons.

The theoretical estimates of the probability of beryllium-7 destruction through one particular reaction, in which the final products are two helium nuclei, are based on a single measurement made in 1963, at the Ispra reactor in Italy.

Image above: In the recently constructed second experimental area of the n_TOF facility, the detector is connected to the read-out system prior to data taking. The neutron beam comes from beneath the picture to hit the beryllium target inside the black cube (Image: n_TOF Collaboration).

The n_TOF collaboration has provided a new, more precise, measurement.  In particular, the aforementioned beryllium-7 distruction reaction resulting in two helium nuclei has been measured for the first time in a wide range of neutron energies with a high accuracy level. This was possible thanks to the extremely high luminosity of the neutron beam in the recently constructed experimental area (EAR2) at the n_TOF facility.  “The new EAR2 offers the unique opportunity to perform such challenging measurements,” says Enrico Chiaveri, spokesperson for the n_TOF collaboration.

The results indicate that, at energies relevant for Big Bang Nucleosynthesis, the probability for that particular reaction leading to the destruction of beryllium-7 is ten times smaller than that used in theoretical calculations. This means that the destruction rate is even smaller than previously supposed, and thus this channel cannot be the solution of the cosmological lithium problem. So the mystery still remains, and maybe the solution for it should be sought among alternative scenarios or within physics beyond the Standard Model.

Read the collaboration’s scientific paper, published in the Physical Review Newsletter (PRL) journal, here: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.152701

Note:

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 link:

n_TOF facility at CERN: https://home.cern/about/experiments/ntof

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Images (mentioned), Text, Credits: CERN/Stefania Pandolfi.

Best regards, Orbiter.ch

Highest Resolution Image of Eta Carinae

ESO - European Southern Observatory logo.

19 October 2016

VLT Interferometer captures raging winds in famous massive stellar system

Detailed look on Eta Carinae

An international team of astronomers have used the Very Large Telescope Interferometer to image the Eta Carinae star system in the greatest detail ever achieved. They found new and unexpected structures within the binary system, including in the area between the two stars where extremely high velocity stellar winds are colliding. These new insights into this enigmatic star system could lead to a better understanding of the evolution of very massive stars.

Highest resolution image of Eta Carinae

Led by Gerd Weigelt from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, a team of astronomers have used the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory to take a unique image of the Eta Carinae star system in the Carina Nebula.

Digitized Sky Survey Image of Eta Carinae Nebula

This colossal binary system consists of two massive stars orbiting each other and is very active, producing stellar winds which travel at velocities of up to ten million kilometres per hour [1]. The zone between the two stars where the winds from each collide is very turbulent, but until now it could not be studied.

The Carina Nebula in the constellation of Carina

The power of the Eta Carinae binary pair creates dramatic phenomena. A “Great Eruption” in the system was observed by astronomers in the 1830s. We now know that this was caused by the larger star of the pair expelling huge amounts of gas and dust in a short amount of time, which led to the distinctive lobes, known as the Homunculus Nebula, that we see in the system today. The combined effect of the two stellar winds as they smash into each other at extreme speeds is to create temperatures of millions of degrees and intense deluges of X-ray radiation.

Panoramic view of the WR 22 and Eta Carinae regions of the Carina Nebula*

The central area where the winds collide is so comparatively tiny — a thousand times smaller than the Homunculus Nebula — that telescopes in space and on the ground so far have not been able to image them in detail. The team has now utilised the powerful resolving ability of the VLTI instrument AMBER to peer into this violent realm for the first time. A clever combination — an interferometer — of three of the four Auxiliary Telescopes at the VLT lead to a tenfold increase in resolving power in comparison to a single VLT Unit Telescope. This delivered the sharpest ever image of the system and yielded unexpected results about its internal structures.

One Picture, Many Stories

The new VLTI image clearly depict the structure which exists between the two Eta Carinae-stars. An unexpected fan-shaped structure was observed where the raging wind from the smaller, hotter star crashes into the denser wind from the larger of the pair.

The Carina Nebula imaged by the VLT Survey Telescope

“Our dreams came true, because we can now get extremely sharp images in the infrared. The VLTI provides us with a unique opportunity to improve our physical understanding of Eta Carinae and many other key objects”, says Gerd Weigelt.

Eta Carinae

In addition to the imaging, the spectral observations of the collision zone made it possible to measure the velocities of the intense stellar winds [2]. Using these velocities, the team of astronomers were able to produce more accurate computer models of the internal structure of this fascinating stellar system, which will help increase our understanding of how these kind of extremely high mass stars lose mass as they evolve.

Zoom on Eta Carinae

Team member Dieter Schertl (MPIfR) looks forward: “The new VLTI instruments GRAVITY and MATISSE will allow us to get interferometric images with even higher precision and over a wider wavelength range. This wide wavelength range is needed to derive the physical properties of many astronomical objects.”

Animation of Eta Carinae and its surrounding

Notes:

[1] The two stars are so massive and bright that the radiation they produce rips off their surfaces and spews them into space. This expulsion of stellar material is referred to as stellar “wind”, and it can travel at millions of kilometres per hour.

[2] Measurements were done through the Doppler effect. Astronomers use the Doppler effect (or shifts) to calculate precisely how fast stars and other astronomical objects move toward or away from Earth. The movement of an object towards or away from us causes a slight shift in its spectral lines. The velocity of the motion can be calculated from this shift.

More information:

This research was presented in a paper to appear in Astronomy and Astrophysics.

The team is composed of G. Weigelt (Max Planck Institute for Radio Astronomy, Germany), K.-H. Hofmann (Max Planck Institute for Radio Astronomy, Germany), D. Schertl (Max Planck Institute for Radio Astronomy, Germany), N. Clementel (South African Astronomical Observatory, South Africa) , M.F. Corcoran (Goddard Space Flight Center, USA; Universities Space Research Association, USA), A. Damineli (Universidade de São Paulo, Brazil ), W.-J. de Wit (European Southern Observatory, Chile), R. Grellmann (Universität zu Köln, Germany), J. Groh (The University of Dublin, Ireland ), S. Guieu (European Southern Observatory, Chile), T. Gull (Goddard Space Flight Center, USA), M. Heininger (Max Planck Institute for Radio Astronomy, Germany) , D.J. Hillier (University of Pittsburgh, USA), C.A. Hummel (European Southern Observatory, Germany), S. Kraus (University of Exeter, UK), T. Madura (Goddard Space Flight Center, USA), A. Mehner (European Southern Observatory, Chile), A. Mérand ( European Southern Observatory, Chile), F. Millour (Université de Nice Sophia Antipolis, France), A.F.J. Moffat (Université de Montréal, Canada), K. Ohnaka (Universidad Católica del Norte, Chile), F. Patru (Osservatorio Astrofisico di Arcetri, Italy), R.G. Petrov (Université de Nice Sophia Antipolis, France), S. Rengaswamy (Indian Institute of Astrophysics, India) , N.D. Richardson (The University of Toledo, USA), T. Rivinius (European Southern Observatory, Chile), M. Schöller (European Southern Observatory, Germany), M. Teodoro (Goddard Space Flight Center, USA) , and M. Wittkowski (European Southern Observatory, 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”.

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1637/eso1637a.pdf

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

3D model of the Homunculus Nebula: http://www.eso.org/public/products/models3d/3dmodel_004/

Simulations of Eta Carinae: https://svs.gsfc.nasa.gov/11725

Very Large Telescope Interferometer (VLTI): http://eso.org/vlt

VLTI instrument AMBER: https://www.eso.org/public/teles-instr/vlt/vlt-instr/amber/

VLT Unit Telescope: https://www.eso.org/public/teles-instr/vlt/vlt-names/

Max Planck Institute for Radio Astronomy (MPIfR): http://www.mpifr-bonn.mpg.de/2169/en

Images, Text, Credits: ESO/Norbert Junkes/Mathias Jäger/Max-Planck-Institut für Radioastronomie/Gerd Weigelt/Dieter Schertl/Digitized Sky Survey 2. Acknowledgment: Davide De Martin/IAU and Sky & Telescope/Acknowledgement: VPHAS+ Consortium/Cambridge Astronomical Survey Unit/Videos: ESO, Digitized Sky Survey 2, A. Fuji, Nick Risinger (skysurvey.org), ESA/Hubble, T. Preibisch. Acknowledgement: VPHAS+ Consortium/Cambridge Astronomical Survey Unit. Music: Johan B. Monell (www.johanmonell.com)/NASA Goddard CI Lab.

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