Powerful Planet Finder Turns Its Eye to the Sky

Gemini Observatory logo.

Jan. 7, 2014

Image above: This image taken by the Gemini Planet Imager (GPI) shows a planet orbiting the star Beta Pictoris. In addition to the image, the GPI obtains spectral information from every pixel element in the field of view, allowing scientists to study the planet in great detail. Image Credit: Gemini/Christian Marois, NRC Canada.

After nearly a decade of development, construction and testing, the world’s most advanced instrument for directly imaging and analyzing planets around other stars is pointing skyward and collecting light from distant worlds.

The instrument, called the Gemini Planet Imager (GPI), was designed, built, and optimized for imaging giant planets next to bright stars, in addition to studying dusty disks around young stars. It is the most advanced instrument of its kind to be deployed on one of the world’s biggest telescopes – the 26-foot (8-meter) Gemini South telescope in Chile.

Image above: Gemini Planet Imager’s first light image of the light scattered by a disk of dust orbiting the young star HR4796A. This narrow ring is thought to be dust from asteroids or comets left behind by planet formation; some scientists have theorized that the sharp edge of the ring is defined by an unseen planet. The left image (1.9-2.1 microns) shows normal light, including both the dust ring and the residual light from the central star scattered by turbulence in the Earth’s atmosphere. The right image shows only polarized light. Leftover starlight is unpolarized and hence removed from this image. The light from the back edge of the disk is strongly polarized as it scatters towards us. Image credit: Processing by Marshall Perrin, Space Telescope Science Institute.

Imaging a planet next to a star is a tricky task. The planet is much fainter than its star, and also appears very close. These challenges make the act of separating the planet's light from the glare of the star difficult. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., contributed to the project by designing and building an ultra-precise infrared sensor to measure small distortions in starlight that might mask a planet.

“Our tasks were two-fold,” said Kent Wallace, JPL’s subsystem technical lead for the project. “First, keep the star centered on the instrument so that its glare is blocked as much as possible. Second, ensure the instrument itself is stable during the very long exposures required to image faint companions.”

Image above: Comparison of Europa observed with Gemini Planet Imager in K1 band on the right and visible albedo visualization based on a composite map made from Galileo SSI and Voyager 1 and 2 data (from USGS) on the left. While GPI is not designed for ‘extended’ objects like this, its observations could help in following surface alterations on icy satellites of Jupiter or atmospheric phenomena (e.g. clouds, haze) on Saturn’s moon Titan. The GPI near-infrared color image is a combination of 3 wavelength channels. Image credit: Processing by Marshall Perrin, Space Telescope Science Institute and Franck Marchis SETI Institute.

GPI detects infrared, or heat, radiation from young Jupiter-like planets in wide orbits around other stars. Those are equivalent to the giant planets in our own solar system not long after their formation. Every planet GPI sees can be studied in detail, revealing components of their atmospheres.

Although GPI was designed to look at distant planets, it can also observe objects in our solar system. Test images of Jupiter’s moon Europa, for example, can allow scientists to map changes in the satellite’s surface composition. The images were released today at the 223rd meeting of the American Astronomical Society in Washington.

Read the full news release from Gemini Observatory at http://www.gemini.edu/node/12113

Images (mentioned), Text, Credits: NASA / JPL / Whitney Clavin.

Cheers, Orbiter.ch

Recently Reactivated NASA Spacecraft Spots Its First New Asteroid

NASA - NEO WISE Mission logo.

Jan. 7, 2014

Image above: The six red dots in this composite picture indicate the location of the first new near-Earth asteroid seen by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). Image Credit: NASA.

NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) spacecraft has spotted a never-before-seen asteroid -- its first such discovery since coming out of hibernation last year.

NEOWISE originally was called the Wide-field Infrared Survey Explorer (WISE), which had made the most comprehensive survey to date of asteroids and comets. The spacecraft was shut down in 2011 after its primary mission was completed. But in September 2013, it was reactivated, renamed and given a new mission, which is to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects (NEOs). NEOWISE also can assist in characterizing previously detected asteroids that could be considered potential targets for future exploration missions.

NEOWISE's first discovery of its renewed mission came on Dec. 29 -- a near-Earth asteroid designated 2013 YP139. The mission's sophisticated software picked out the moving object against a background of stationary stars. As NEOWISE circled Earth scanning the sky, it observed the asteroid several times over half a day before the object moved beyond its view. Researchers at the University of Arizona used the Spacewatch telescope at the Kitt Peak National Observatory southwest of Tucson to confirm the discovery. Peter Birtwhistle, an amateur astronomer at the Great Shefford Observatory in West Berkshire, England, also contributed follow-up observations. NASA expects 2013 YP139 will be the first of hundreds of asteroid discoveries for NEOWISE.

"We are delighted to get back to finding and characterizing asteroids and comets, especially those that come into Earth’s neighborhood," said Amy Mainzer, the mission's principal investigator from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "With our infrared sensors that detect heat, we can learn about their sizes and reflectiveness."

2013 YP139 is about 27 million miles (43 million kilometers) from Earth. Based on its infrared brightness, scientists estimate it to be roughly 0.4 miles (650 meters) in diameter and extremely dark, like a piece of coal. The asteroid circles the sun in an elliptical orbit tilted to the plane of our solar system and is classified as potentially hazardous. It is possible for its orbit to bring it as close as 300,000 miles from Earth, a little more than the distance to the moon. However, it will not come that close within the next century.

WISE discovered more than 34,000 asteroids and characterized 158,000 throughout the solar system during its prime mission in 2010 and early 2011. Its reactivation in September followed 31 months in hibernation.

WISE Reactivated to Hunt for Asteroids. Image Credit: NASA

NEOWISE will continue to detect asteroids and comets. The observations will be automatically sent to the clearinghouse for solar system bodies, the Minor Planet Center in Cambridge, Mass., for comparison against the known catalog of solar system objects and to determine orbit if the object is not known. A community of professional and amateur astronomers will provide follow-up observations, establishing firm orbits for the previously unseen objects.   Infrared sensors, similar to the cameras on NEOWISE, are a powerful tool for discovering, cataloging and understanding the asteroid population. Some of the objects about which NEOWISE will be collecting data could become candidates for NASA's announced asteroid initiative, which will be the first mission to identify, capture and relocate an asteroid for astronauts to explore. The initiative represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities that will help protect our home planet and achieve the goal of sending humans to an asteroid by 2025.

JPL manages the project for NASA's Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

An image of asteroid 2013 YP139, taken by NEOWISE, is available at: http://go.nasa.gov/1cNF9T7

More information about NEOWISE is available online at: http://www.nasa.gov/wise

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

Best regards, Orbiter.ch

Pandora's magnifying glass

ESA Hubble Space Telescope logo.

7 January 2014

First image from Hubble's Frontier Fields

Hubble Frontier Fields view of Abell 2744

This image of Abell 2744 is the first to come from Hubble's Frontier Fields observing programme, which is using the magnifying power of enormous galaxy clusters to peer deep into the distant Universe. Abell 2744, nicknamed Pandora's Cluster, is thought to have a very violent history, having formed from a cosmic pile-up of multiple galaxy clusters.

Astronomers previously observed Abell 2744 with the NASA/ESA Hubble Space Telescope back in 2011, exploring the cluster's history. They found that at least four galaxy clusters had crashed into one another to form Abell 2744, causing some weird and wonderful effects. This mix of cosmic phenomena, some of which had never been seen before, led to the nickname of Pandora's Cluster (heic1111).

A mix of hazy elliptical galaxies and colourful spirals can be seen clumping together in the centre of this image. The effects of the cluster's gravity can be seen in the blue arcs and distorted shapes that are scattered across the frame, including galaxies that seem to be bleeding into the surrounding space. The arcs are actually the distorted images of galaxies far in the distance.

Abell 2744 is the first of six targets for an observing programme known as Frontier Fields. This three-year, 840-orbit programme [1] will yield our deepest views of the Universe to date, using the power of Hubble to explore more distant regions of space than could otherwise be seen, by observing gravitational lensing effects around six different galaxy clusters.

Gravitational lensing is a phenomenon caused by an object's influence on the space-time around it. Massive objects like galaxy clusters [2] warp and distort this space-time. This causes light from more distant objects hidden behind this makeshift lens to be deflected and bent, leading to a bizarre array of optical effects — for example, it caused a cosmic space invader to appear around cluster Abell 68 (heic1304) by creating mirror images of one galaxy, as well as smearing galaxies out into arcs, and creating multiple images of individual objects.

Hubble Space Telescope

As well as creating these weird shapes, lensing also magnifies the images so that astronomers can see more detail. This means that distant objects that otherwise would be too distant and faint to be seen become visible — something that Frontier Fields aims to exploit over the coming years.

Some results from this programme are already starting to emerge, with Abell 2744 as the first target. In a new paper submitted to The Astrophysical Journal on 29 November 2013 (available on the ArXiv Preprint Server), a group of astronomers detected a large number of distant, gravitationally lensed galaxy candidates — all viewed through Abell 2744, with the galaxy cluster acting as a lens. They also found that five of these candidates are part of distant systems that appear to have been imaged multiple times due to the cluster's gravitational lensing effects. These deep surveys using massive galaxy clusters like Abell 2744 show that looking through cosmic lenses can be an effective and useful way to study the distant Universe. For more information on gravitational lensing see Hubblecast 70: Peering around cosmic corners.

This image is part of the first set of super-deep views of the Universe obtained by the Frontier Fields observing program, and is being released today, 7 January 2014, at the 223rd meeting of the American Astronomical Society in Washington, DC, USA.

Notes:

[1] A typical Hubble observing programme lasts from a few to a few tens of orbits.

[2] All objects that have mass affect the space around them in this way, but huge clumps of mass like galaxy clusters do so more strongly.

Notes for editors:

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

Links:

ESA/Hubble Science Announcement: Start of Hubble Frontier Fields observations: http://www.spacetelescope.org/forscientists/announcements/sci13006/

ArXiv Preprint Server: http://arxiv.org/abs/1311.7670

Hubblecast 70: Peering around cosmic corners: http://www.spacetelescope.org/videos/hubblecast70a/

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

Image, Text, Credits: NASA, ESA, and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI).

Greetings, Orbiter.ch

SpaceX Successfully Launches THAICOM 6 Satellite to Geostationary Transfer Orbit

SpaceX - Falcon 9 / THAICOM 6 Satellite launch patch.

Jan. 7, 2014

Falcon 9 rocket launch THAICOM 6 Satellite

THAICOM 6 mission marks second successful GTO flight for the upgraded Falcon 9 launch vehicle

Cape Canaveral Air Force Station, Florida – Today, Space Exploration Technologies (SpaceX) successfully launched the THAICOM 6 satellite for leading Asian satellite operator THAICOM.  Falcon 9 delivered THAICOM 6 to its targeted 295 x 90,000 km geosynchronous transfer orbit at 22.5 degrees inclination.  The Falcon 9 launch vehicle performed as expected, meeting 100% of mission objectives.

SpaceX Launch of Thaicom-6 on Falcon 9v1.1 Rocket

Falcon 9 lifted off from Space Launch Complex 40 (SLC-40) at 5:06 PM Eastern Time.  Approximately 184 seconds into flight, Falcon 9’s second stage’s single Merlin vacuum engine ignited to begin a five minute, 35 second burn that delivered the THAICOM 6 satellite into its parking orbit. Eighteen minutes after injection into the parking orbit, the second stage engine relit for just over one minute to carry the THAICOM 6 satellite to its final geostationary transfer orbit.  The restart of the Falcon 9 second stage is a requirement for all geostationary transfer missions.

THAICOM 6 satellite

“Today’s successful launch of the THAICOM 6 satellite marks the eighth successful flight in a row for Falcon 9,” said Gwynne Shotwell, President of SpaceX. “SpaceX greatly appreciates THAICOM’s support throughout this campaign and we look forward to a busy launch schedule in 2014.”  

The THAICOM 6 mission marks Falcon 9’s second flight to a geosynchronous transfer orbit and begins a regular cadence of launches planned for SpaceX in 2014. SpaceX has nearly 50 launches on manifest, of which over 60% are for commercial customers.

THAICOM 6 satellite mission description

This launch also marks the third of three qualification flights needed to certify the Falcon 9 to fly missions under the Evolved Expendable Launch Vehicle (EELV) program. Once Falcon 9 is certified, SpaceX will be eligible to compete to launch national security satellites for the U.S. Air Force.

About SpaceX:

SpaceX designs, manufactures, and launches the world's most advanced rockets and spacecraft. The company was founded in 2002 by Elon Musk to revolutionize space transportation, with the ultimate goal of enabling people to live on other planets. Today, SpaceX is advancing the boundaries of space technology through its Falcon launch vehicles and Dragon spacecraft. SpaceX is a private company owned by management and employees, with minority investments from Founders Fund, Draper Fisher Jurvetson, and Valor Equity Partners. The company has more than 3,000 employees in California, Texas, Washington, D.C., and Florida. For more information, visit http://www.spacex.com

Images, Video, Text, Credit: SpaceX.

Greetings, Orbiter.ch

NASA's Kepler Provides Insights on Enigmatic Planets

NASA - Kepler Mission patch.

January 7, 2014

More than three-quarters of the planet candidates discovered by NASA's Kepler spacecraft have sizes ranging from that of Earth to that of Neptune, which is nearly four times as big as Earth. Such planets dominate the galactic census but are not represented in our own solar system. Astronomers don't know how they form or if they are made of rock, water or gas.

The Kepler team today reports on four years of ground-based follow-up observations targeting Kepler's exoplanet systems at the American Astronomical Society meeting in Washington. These observations confirm the numerous Kepler discoveries are indeed planets and yield mass measurements of these enigmatic worlds that vary between Earth and Neptune in size.

Included in the findings are five new rocky planets ranging in size from 10 to 80 percent larger than Earth. Two of the new rocky worlds, dubbed Kepler-99b and Kepler-406b, are both 40 percent larger in size than Earth and have a density similar to lead. The planets orbit their host stars in less than five and three days respectively, making these worlds too hot for life as we know it.

Artist's concept of NASA's Kepler space telescope. Image credit: NASA/JPL-Caltech

A major component of these follow-up observations was Doppler measurements of the planets' host stars. The team measured the reflex wobble of the host star, caused by the gravitational tug on the star exerted by the orbiting planet. That measured wobble reveals the mass of the planet: the higher the mass of the planet, the greater the gravitational tug on the star and hence the greater the wobble.

"This marvelous avalanche of information about the mini-Neptune planets is telling us about their core-envelope structure, not unlike a peach with its pit and fruit," said Geoff Marcy, professor of astronomy at the University of California, Berkeley, who led the summary analysis of the high-precision Doppler study. "We now face daunting questions about how these enigmas formed and why our solar system is devoid of the most populous residents in the galaxy."

Using one of the world's largest ground-based telescopes at the W. M. Keck Observatory in Hawaii, scientists confirmed 41 of the exoplanets discovered by Kepler and determined the masses of 16. With the mass and diameter in hand, scientists could immediately determine the density of the planets, characterizing them as rocky or gaseous, or mixtures of the two.

The density measurements dictate the possible chemical composition of these strange, but ubiquitous planets. The density measurements suggest that the planets smaller than Neptune -- or mini-Neptunes -- have a rocky core but the proportions of hydrogen, helium and hydrogen-rich molecules in the envelope surrounding that core vary dramatically, with some having no envelope at all.

The ground-based observation research validates 38 new planets, six of which are non-transiting planets only seen in the Doppler data. The paper detailing the research is published in the Astrophysical Journal today.

Chart of Kepler planet candidates as of January 2014. Image Credit: NASA Ames

A complementary technique used to determine mass, and in turn density of a planet, is by measuring the transit timing variations (TTV). Much like the gravitational force of a planet on its star, neighboring planets can tug on one another, causing one planet to accelerate and another planet to decelerate along its orbit.

Ji-Wei Xie of the University of Toronto used TTV to validate 15 pairs of Kepler planets ranging from Earth-sized to a little larger than Neptune. Xie measured masses of the 30 planets, thereby adding to the compendium of planetary characteristics for this new class of planets. The result also was published in the Astrophysical Journal in Dec. 2013.

"Kepler's primary objective is to determine the prevalence of planets of varying sizes and orbits. Of particular interest to the search for life is the prevalence of Earth-sized planets in the habitable zone," said Natalie Batalha, Kepler mission scientist at NASA's Ames Research Center in Moffett Field, Calif. "But the question in the back of our minds is: are all planets the size of Earth rocky? Might some be scaled-down versions of icy Neptunes or steamy water worlds? What fraction are recognizable as kin of our rocky, terrestrial globe?"

Artist's view of a Earth-size rocky exoplanet. Image credit: NASA/JPL-Caltech

The dynamical mass measurements produced by Doppler and TTV analyses will help to answer these questions. The results hint that a large fraction of planets smaller than 1.5 times the radius of Earth may be comprised of the silicates, iron, nickel and magnesium that are found in the terrestrial planets here in the solar system.

Armed with this type of information, scientists will be able to turn the fraction of stars harboring Earth-sizes planets into the fraction of stars harboring bona-fide rocky planets. And that's a step closer to finding a habitable environment beyond the solar system.

Ames is responsible for the Kepler mission concept, ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery mission and was funded by the agency's Science Mission Directorate.

For more information about the Kepler space telescope, visit: http://www.nasa.gov/kepler .

The California Institute of Technology in Pasadena manages JPL for NASA.

Images (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Michele Johnson / Ames Research Center / Michele Johnson.

Best regards, Orbiter.ch

NASA's Fermi Makes First Gamma-ray Study of a Gravitational Lens

NASA - Fermi Gamma-ray Space Telescope logo.

Jan. 6, 2014

An international team of astronomers, using NASA's Fermi observatory, has made the first-ever gamma-ray measurements of a gravitational lens, a kind of natural telescope formed when a rare cosmic alignment allows the gravity of a massive object to bend and amplify light from a more distant source.

This accomplishment opens new avenues for research, including a novel way to probe emission regions near supermassive black holes. It may even be possible to find other gravitational lenses with data from the Fermi Gamma-ray Space Telescope.

Gravitational Lens B0218+357

Video above: This movie illustrates the components of a gravitational lens system known as B0218+357. Different sight lines to a background blazar result in two images that show outbursts at slightly different times. NASA's Fermi made the first gamma-ray measurements of this delay in a lens system. Image Credit: NASA's Goddard Space Flight Center.

"We began thinking about the possibility of making this observation a couple of years after Fermi launched, and all of the pieces finally came together in late 2012," said Teddy Cheung, lead scientist for the finding and an astrophysicist at the Naval Research Laboratory in Washington.

In September 2012, Fermi's Large Area Telescope (LAT) detected a series of bright gamma-ray flares from a source known as B0218+357, located 4.35 billion light-years from Earth in the direction of a constellation called Triangulum. These powerful flares, in a known gravitational lens system, provided the key to making the lens measurement.

Astronomers classify B0218+357 as a blazar -- a type of active galaxy noted for its intense emissions and unpredictable behavior. At the blazar's heart is a supersized black hole with a mass millions to billions of times that of the sun. As matter spirals toward the black hole, some of it blasts outward as jets of particles traveling near the speed of light in opposite directions.

The extreme brightness and variability of blazars result from a chance orientation that brings one jet almost directly in line with Earth. Astronomers effectively look down the barrel of the jet, which greatly enhances its apparent emission.

Image above: This Hubble image of gravitational lens B0218+357 reveals two bright sources separated by about a third of an arcsecond, each an image of the background blazar. Spiral arms belonging to the lensing galaxy also can be seen. B0218+357 boasts the smallest separation of lensed images currently known. Image Credit: NASA/ESA and the Hubble Legacy Archive.

Long before light from B0218+357 reaches us, it passes directly through a face-on spiral galaxy -- one very much like our own -- about 4 billion light-years away.

The galaxy's gravity bends the light into different paths, so astronomers see the background blazar as dual images. With just a third of an arcsecond (less than 0.0001 degree) between them, the B0218+357 images hold the record for the smallest separation of any lensed system known.

While radio and optical telescopes can resolve and monitor the individual blazar images, Fermi's LAT cannot. Instead, the Fermi team exploited a "delayed playback" effect.

"One light path is slightly longer than the other, so when we detect flares in one image we can try to catch them days later when they replay in the other image," said team member Jeff Scargle, an astrophysicist at NASA's Ames Research Center in Moffett Field, Calif.

Image above: In the heart of an active galaxy, matter falling toward a supermassive black hole creates jets of particles traveling near the speed of light. For active galaxies classified as blazars, one of these jets beams almost directly toward Earth. Image Credit: NASA/Goddard Space Flight Center Conceptual Image Lab.

In September 2012, when the blazar's flaring activity made it the brightest gamma-ray source outside of our own galaxy, Cheung realized it was a golden opportunity. He was granted a week of LAT target-of-opportunity observing time, from Sept. 24 to Oct. 1, to hunt for delayed flares.

At the American Astronomical Society meeting in National Harbor, Md., Cheung said the team had identified three episodes of flares showing playback delays of 11.46 days, with the strongest evidence found in a sequence of flares captured during the week-long LAT observations.

Intriguingly, the gamma-ray delay is about a day longer than radio observations report for this system. And while the flares and their playback show similar gamma-ray brightness, in radio wavelengths one blazar image is about four times brighter than the other.

Astronomers don't think the gamma rays arise from the same regions as the radio waves, so these emissions likely take slightly different paths, with correspondingly different delays and amplifications, as they travel through the lens.

"Over the course of a day, one of these flares can brighten the blazar by 10 times in gamma rays but only 10 percent in visible light and radio, which tells us that the region emitting gamma rays is very small compared to those emitting at lower energies," said team member Stefan Larsson, an astrophysicist at Stockholm University in Sweden.

As a result, the gravity of small concentrations of matter in the lensing galaxy may deflect and amplify gamma rays more significantly than lower-energy light. Disentangling these so-called microlensing effects poses a challenge to taking further advantage of high-energy lens observations.

Image above: This interactive illustrates how gravitational lensing can be observed by NASA's Fermi Gamma-ray Space Telescope. Image Credit: NASA's Goddard Space Flight Center.
View interactive: http://www.nasa.gov/externalflash/fermi_gravitational_lensing/

The scientists say that comparing radio and gamma-ray observations of additional lens systems could help provide new insights into the workings of powerful black-hole jets and establish new constraints on important cosmological quantities like the Hubble constant, which describes the universe's rate of expansion.

The most exciting result, the team said, would be the LAT's detection of a playback delay in a flaring gamma-ray source not yet identified as a gravitational lens in other wavelengths.

A paper describing the research will appear in a future edition of The Astrophysical Journal Letters.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership. Fermi is managed by NASA's Goddard Space Flight Center in Greenbelt, Md. It was developed in collaboration with the U.S. Department of Energy, with contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

Related Links:

Download multimedia in HD formats: http://svs.gsfc.nasa.gov/vis/a010000/a011400/a011437/

NASA's Fermi website: http://www.nasa.gov/fermi

Paper: "Fermi-LAT Detection of Gravitational Lens Delayed  Gamma-ray Flares from  Blazar B0218+357" (preprint): http://arxiv.org/abs/1401.0548

Interactive: Gravitational Lensing: http://www.nasa.gov/externalflash/fermi_gravitational_lensing/

Images (mentioned), Video, Text, Credits: NASA / J. D. Harrington / Goddard Space Flight Center / Lynn Chandler.

Greetings, Orbiter.ch

ALMA Spots Supernova Dust Factory

ESO - European Southern Observatory logo.

6 January 2014

Composite image of Supernova 1987A

Striking new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope capture, for the first time, the remains of a recent supernova brimming with freshly formed dust. If enough of this dust makes the perilous transition into interstellar space, it could explain how many galaxies acquired their dusty, dusky appearance.

Galaxies can be remarkably dusty places [1] and supernovae are thought to be a primary source of that dust, especially in the early Universe. But direct evidence of a supernova's dust‐making capabilities has been slim up to now, and could not account for the copious amount of dust detected in young, distant galaxies. But now observations with ALMA are changing that.

"We have found a remarkably large dust mass concentrated in the central part of the ejecta from a relatively young and nearby supernova," said Remy Indebetouw, an astronomer at the National Radio Astronomy Observatory (NRAO) and the University of Virginia, both in Charlottesville, USA. "This is the first time we've been able to really image where the dust has formed, which is important in understanding the evolution of galaxies."

An international team of astronomers used ALMA to observe the glowing remains of Supernova 1987A [2], which is in the Large Magellanic Cloud, a dwarf galaxy orbiting the Milky Way about 160 000 light‐years from Earth. SN 1987A is the closest observed supernova explosion since Johannes Kepler's observation of a supernova inside the Milky Way in 1604.

Artist's illustration of Supernova 1987A

Astronomers predicted that as the gas cooled after the explosion, large amounts of dust would form as atoms of oxygen, carbon, and silicon bonded together in the cold central regions of the remnant. However, earlier observations of SN 1987A with infrared telescopes, made during the first 500 days after the explosion, detected only a small amount of hot dust.

With ALMA's unprecedented resolution and sensitivity, the research team was able to image the far more abundant cold dust, which glows brightly in millimetre and submillimetre light. The astronomers estimate that the remnant now contains about 25 percent the mass of the Sun in newly formed dust. They also found that significant amounts of carbon monoxide and silicon monoxide have formed.

"SN 1987A is a special place since it hasn't mixed with the surrounding environment, so what we see there was made there," said Indebetouw. "The new ALMA results, which are the first of their kind, reveal a supernova remnant chock full of material that simply did not exist a few decades ago."

Supernovae, however, can both create and destroy dust grains.

Portrait of a Dramatic Stellar Crib*

As the shockwave from the initial explosion radiated out into space, it produced bright glowing rings of material, as seen in earlier observations with the NASA/ESA Hubble Space Telescope. After hitting this envelope of gas, which was sloughed off by the progenitor red giant star as it neared the end of its life, a portion of this powerful explosion rebounded back towards the centre of the remnant. "At some point, this rebound shockwave will slam into these billowing clumps of freshly minted dust," said Indebetouw. "It's likely that some fraction of the dust will be blasted apart at that point. It's hard to predict exactly how much — maybe only a little, possibly a half or two thirds." If a good fraction survives and makes it into interstellar space, it could account for the copious dust astronomers detect in the early Universe.

"Really early galaxies are incredibly dusty and this dust plays a major role in the evolution of galaxies," said Mikako Matsuura of University College London, UK. "Today we know dust can be created in several ways, but in the early Universe most of it must have come from supernovae. We finally have direct evidence to support that theory."

Notes:

[1] Cosmic dust consist of silicate and graphite grains — minerals also abundant on Earth. The soot from a candle is very similar to cosmic graphite dust, although the size of the grains in the soot are ten or more times bigger than typical grain sizes of cosmic graphite grains.

[2] Light from this supernova arrived at Earth in 1987, as is reflected in the name.

More information:

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

This research was presented in a paper “Dust Production and Particle Acceleration in Supernova 1987A Revealed with ALMA”, by R. Indebetouw et al., to appear in the Astrophysical Journal Letters.

The team is composed of R. Indebetouw (National Radio Astronomy Observatory (NRAO); University of Virginia, Charlottesville, USA), M. Matsuura (University College London, United Kingdom [UCL]), E. Dwek (NASA Goddard Space Flight Center, Greenbelt, USA), G. Zanardo (International Centre for Radio Astronomy Research, University of Western Australia, Crawley, Australia [ICRAR]), M.J. Barlow (UCL), M. Baes (Sterrenkundig Obst Gent, Gent, Belgium), P. Bouchet (CEA-Saclay, Gif-sur-Yvette, France), D.N. Burrows (The Pennsylvania State University, University Park, USA), R. Chevalier (University of Virginia, Charlottesville, USA), G.C. Clayton (Louisiana State University, Baton Rouge,USA), C. Fransson (Stockholm University, Sweden), B. Gaensler (Australian Research Council Centre of Excellence for All-sky Astrophysics [CAASTRO]; Sydney Institute for Astronomy, The University of Sydney, Australia), R. Kirshner (Harvard-Smithsonian Center for Astrophysics, Cambridge, USA), M.Lakicevic (Lennard-Jones Laboratories, Keele University, UK), K.S. Long (Space Telescope Science Institute, Baltimore, USA [STScI]), P. Lundqvist (Stockholm University, Sweden), I. Martí-Vidal (Chalmers University of Technology, Onsala Space Observatory, Onsala, Sweden), J. Marcaide (Universidad de Valencia, Burjassot, Spain), R. McCray (University of Colorado at Boulder, USA), M. Meixner (STScI; The Johns Hopkins University, Baltimore, USA), C.-Y. Ng (The University of Hong Kong, Hong Kong), S. Park (University of Texas at Arlington, Arlington, USA), G. Sonneborn (STScI), L. Staveley-Smith (ICRAR; CAASTRO), C. Vlahakis (Joint ALMA Observatory/European Southern Observatory, Santiago, Chile) and J. van Loon (Lennard-Jones Laboratories, Keele University, UK).

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

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1401/eso1401a.pdf

More about ALMA: http://www.eso.org/public/teles-instr/alma/

Photos of ALMA: http://www.eso.org/public/images/archive/category/alma/

Images, Text, Credits: ALMA (ESO/NAOJ/NRAO)/A. Angelich. Visible light image: the NASA/ESA Hubble Space Telescope. X-Ray image: The NASA Chandra X-Ray Observatory//Alexandra Angelich (NRAO/AUI/NSF)/R. Fosbury (ST-ECF).

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