samedi 19 mai 2018

Orbital ATK Antares Rocket Set for Early Monday Morning Launch to Space Station Space Station Research












NASA / Orbital ATK - Cygnus OA-9 Mission patch.

May 19, 2018


Image above: Antares rocket arrival at Pad 0A of Virginia Space’s Mid-Atlantic Regional Spaceport at Wallops. Image Credits: NASA/Aubrey Gemignani.

The Range Control Center at NASA’s Wallops Flight Facility has forecast 70-percent favorable weather for the May 21 launch of Orbital ATK’s Antares rocket from the Mid-Atlantic Regional Spaceport at NASA’s Wallops Flight Facility on Virginia’s Eastern Shore.

Antares rocket being raised at launchpad. Image Credit: NASA/Aubrey Gemignani.

The main weather concern for Monday’s launch attempt is sky screen (essentially local visibility conditions). Latest launch forecast puts weather at 70 percent favorable.


Animation above: Time-lapse of Antares rocket being raised at launchpad. Animation Credit: NASA’s Wallops Flight Facility/Patrick Black.

A weak cold front looks to drop into the region late Sunday afternoon, May 20, providing a chance for scattered showers and thunderstorms through that evening. Shower chances diminish by early Monday, but a weak upper-level impulse drops over the Eastern Shore during the overnight hours Sunday into Monday, providing increased cloud cover and a slight chance for an isolated shower leading up to the projected launch.


Image above: The Orbital ATK Antares rocket, with the Cygnus spacecraft on board, raised at launchpad. Image Credit: NASA’s Wallops Flight Facility/Patrick Black.

The Antares rocket, with Orbital ATK’s Cygnus spacecraft aboard is scheduled to launch no earlier than May 21 at 4:39 a.m. EDT on the company’s CRS-9 resupply mission to the International Space Station.


Image above: The Orbital ATK Antares rocket, with the Cygnus spacecraft on board, is raised at launch Pad-0A, Friday, May 18, 2018, at NASA’s Wallops Flight Facility in Virginia. Photo Credit: NASA/Aubrey Gemignani.

The mission, CRS-9, is Orbital ATK’s ninth contracted cargo delivery flight to the International Space Station for NASA. Among the 7,400 pounds of cargo aboard Cygnus are science experiments, crew supplies and vehicle hardware.

Related links:

NASA TV coverage: https://www.nasa.gov/ntv

Learn more about Orbital ATK’s mission at: http://www.nasa.gov/orbitalatk

Commercial Resupply: https://www.nasa.gov/mission_pages/station/structure/launch/index.html

Images (mentioned), Text, Credits: NASA/Rob Garner.

Best regards, Orbiter.ch

Hubble Catches a Spiral Galaxy in Disguise












NASA - Hubble Space Telescope patch.

May 19, 2018


Resembling a wizard’s staff set aglow, NGC 1032 cleaves the quiet darkness of space in two in this image from the NASA/ESA Hubble Space Telescope.

NGC 1032 is located about a hundred million light-years away in the constellation Cetus (the Sea Monster). Although beautiful, this image perhaps does not do justice to the galaxy’s true aesthetic appeal: NGC 1032 is actually a spectacular spiral galaxy, but from Earth, the galaxy’s vast disk of gas, dust and stars is seen nearly edge-on.

A handful of other galaxies can be seen lurking in the background, scattered around the narrow strip of NGC 1032. Many are oriented face-on or at tilted angles, showing off their glamorous spiral arms and bright cores. Such orientations provide a wealth of detail about the arms and their nuclei, but fully understanding a galaxy’s three-dimensional structure also requires an edge-on view. This gives astronomers an overall idea of how stars are distributed throughout the galaxy and allows them to measure the “height” of the disk and the bright star-studded core.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Image, Animation, Text, Credits: ESA/Hubble & NASA/Text: European Space Agency/NASA/Karl Hille.

Greetings, Orbiter.ch

Jupiter: A New Perspective












NASA - JUNO Mission logo.

May 19, 2018


This extraordinary view of Jupiter was captured by NASA’s Juno spacecraft on the outbound leg of its 12th close flyby of the gas giant planet.

This new perspective of Jupiter from the south makes the Great Red Spot appear as though it is in northern territory. This view is unique to Juno and demonstrates how different our view is when we step off the Earth and experience the true nature of our three-dimensional universe.

Juno took the images used to produce this color-enhanced image on April 1 between 3:04 a.m. PDT (6:04 a.m. EDT) and 3:36 a.m. PDT (6:36 a.m. EDT). At the time the images were taken, the spacecraft was between 10,768 miles (17,329 kilometers) to 42,849 miles (68,959 kilometers) from the tops of the clouds of the planet at a southern latitude spanning 34.01 to 71.43 degrees.

Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft’s JunoCam imager. The view is a composite of several separate JunoCam images that were re-projected, blended, and healed.

Juno orbiting Jupiter

JunoCam's raw images are available for the public to peruse and process into image products at: http://www.missionjuno.swri.edu/junocam  

More information about Juno is at: https://www.nasa.gov/juno and http://missionjuno.swri.edu

Image, Animation, Text, Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Gerald Eichstäd/Seán Doran.

Greetings, Orbiter.ch

vendredi 18 mai 2018

Cygnus Rolls Out to Pad Targeting Monday Launch











ISS - Expedition 55 Mission patch.

May 18, 2018

The Orbital ATK Cygnus cargo craft that will resupply the Expedition 55 crew on the International Space Station rolled out to its launch pad Thursday night. Cygnus is now targeted to blast off atop the Antares rocket Monday at 4:39 a.m. EDT from Wallops Flight Facility in Virginia. NASA TV will begin its live broadcast of the launch Monday at 4 a.m.

Orbital ATK and NASA managers moved Cygnus’ launch to no earlier than Monday to support further pre-launch inspections and more favorable weather conditions. Monday shows an 80% probability of acceptable weather for launch.

Cygnus is packed with 7,400 pounds of new science experiments, crew supplies and space station hardware. It is scheduled to arrive Thursday at the space station for its robotic capture at 5:20 a.m. NASA TV will cover the approach and rendezvous activities starting at 3:30 a.m.


Image above: The Antares rocket from Orbital ATK makes its way to the launch pad at Wallops Flight Facility in Virginia. The Antares will launch the Cygnus spacecraft on a cargo resupply mission to the International Space Station. Image Credit: Orbital ATK.

Three NASA astronauts, Scott Tingle, Ricky Arnold and Drew Feustel, have trained for weeks to get ready for Cygnus’ arrival on Thursday. Tingle will be operating the Canadarm2 from inside the Cupola and command the robotic arm to grapple Cygnus. Arnold will back him up on the robotics controls and Feustel will monitor Cygnus and it systems during its approach. Robotics engineers on the ground will then remotely install the commercial space freighter on the Earth-facing port of the Unity module later Thursday morning.

One of the new experiments being delivered aboard Cygnus to the orbital laboratory will study atoms frozen to a temperature 10 billion times colder than deep space. The Cold Atom Lab will observe the quantum phenomena possibly leading to advanced spacecraft navigation techniques and quantum sensors that can detect gravitational and magnetic fields.

Related articles:

Small Packages to Test Big Space Technology Advances
https://orbiterchspacenews.blogspot.ch/2018/05/small-packages-to-test-big-space.html

Science Launching to Space Station Looks Forward and Back
https://orbiterchspacenews.blogspot.ch/2018/05/science-launching-to-space-station.html

Related links:

Orbital ATK: https://www.nasa.gov/orbital

NASA TV: https://www.nasa.gov/press-release/nasa-tv-coverage-set-for-next-resupply-mission-to-space-station

Expedition 55: https://www.nasa.gov/mission_pages/station/expeditions/expedition55/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

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

Best regards, Orbiter.ch

NASA’s New Planet Hunter Snaps Initial Test Image, Swings by Moon Toward Final Orbit












NASA - TESS Mission logo.

May 18, 2018


Image above: An illustration of TESS as it passed the Moon during its lunar flyby. This provided a gravitational boost that placed TESS on course for its final working orbit. Image Credits: NASA's Goddard Space Flight Center.

NASA’s next planet hunter, the Transiting Exoplanet Survey Satellite (TESS), is one step closer to searching for new worlds after successfully completing a lunar flyby on May 17. The spacecraft passed about 5,000 miles from the Moon, which provided a gravity assist that helped TESS sail toward its final working orbit.

As part of camera commissioning, the science team snapped a two-second test exposure using one of the four TESS cameras. The image, centered on the southern constellation Centaurus, reveals more than 200,000 stars. The edge of the Coalsack Nebula is in the right upper corner and the bright star Beta Centauri is visible at the lower left edge. TESS is expected to cover more than 400 times as much sky as shown in this image with its four cameras during its initial two-year search for exoplanets. A  science-quality image, also referred to as a “first light” image, is expected to be released in June.


Image above: This test image from one of the four cameras aboard the Transiting Exoplanet Survey Satellite (TESS) captures a swath of the southern sky along the plane of our galaxy. TESS is expected to cover more than 400 times the amount of sky shown in this image when using all four of its cameras during science operations. Image Credits: NASA/MIT/TESS.

TESS will undergo one final thruster burn on May 30 to enter its science orbit around Earth. This highly elliptical orbit will maximize the amount of sky the spacecraft can image, allowing it to continuously monitor large swaths of the sky. TESS is expected to begin science operations in mid-June after reaching this orbit and completing camera calibrations.

The Unique Orbit of NASA's Planet Hunter

Video above: An animation of the steps TESS must complete before reaching its final orbit. The observatory just completed its lunar flyby and is on track to reach its final science orbit in mid-June. Video Credits: NASA's Goddard Space Flight Center.

Launched from Cape Canaveral Air Force Station in Florida on April 18, TESS is the next step in NASA’s search for planets outside our solar system, known as exoplanets. The mission will observe nearly the entire sky to monitor nearby, bright stars in search of transits — periodic dips in a star’s brightness caused by a planet passing in front of the star. TESS is expected to find thousands of exoplanets. NASA’s upcoming James Webb Space Telescope, scheduled for launch in 2020, will provide important follow-up observations of some of the most promising TESS-discovered exoplanets, allowing scientists to study their atmospheres.

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Dr. George Ricker of MIT’s Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Orbital ATK, based in Dulles, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; and the Space Telescope Science Institute in Baltimore. The TESS science instruments were jointly developed by MIT’s Kavli Institute for Astrophysics and Space Research and MIT’s Lincoln Laboratory. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

TESS (Transiting Exoplanet Survey Satellite): http://www.nasa.gov/tess

Images (mentioned), Video (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Claire Saravia.

Greetings, Orbiter.ch

Small Packages to Test Big Space Technology Advances












NASA / Orbital ATK - Cygnus OA-9 Mission patch.

May 18, 2018

This weekend, when the next cargo resupply mission to the International Space Station lifts off from NASA Wallops Flight Facility in Virginia, it will be carrying among its supplies and experiments three cereal box-sized satellites that will be used to test and demonstrate the next generation of Earth-observing technology.

NASA has been increasing its use of CubeSats -- small satellites based on several configurations of approximately 4 x 4 x 4-inch cubes -- to put new technologies in orbit where they can be tested in the harsh environment of space before being used as part of larger satellite missions or constellations of spacecraft.

The three CubeSat missions launching on Orbital ATK’s ninth commercial resupply mission represent a broad range of cutting-edge technologies housed in very small packages.

RainCube -- a Radar in a CubeSat -- is just that: a miniaturized precipitation-studying radar instrument that weighs just over 26 pounds. RainCube is smaller, has fewer components, and uses less power than traditional radar instruments. NASA’s Earth Science Technology Office (ESTO) In-Space Validation of Earth Science Technologies (InVEST) program selected the project to demonstrate that such a diminutive radar can be operated successfully on a CubeSat platform.


Image above: The complete TEMPEST-D spacecraft shown with the solar panels deployed. Image Credits: Credit: Blue Canyon Technologies.

This mission marks the first time an active radar instrument has been flown on a CubeSat.

If successful, RainCube could open the door for lower-cost, quick-turnaround constellation missions, in which multiple CubeSats work together to provide more frequent observations than a single satellite. 

“A constellation of RainCube radars would be able to observe the internal structure of weather systems as they evolve according to processes that need to be better characterized in weather and climate forecasting models,” said RainCube Principal Investigator Eva Peral of NASA’s Jet Propulsion Laboratory in Pasadena, California.

RainCube will use wavelengths in the high-frequency Ka-band of the electromagnetic spectrum. Ka wavelengths work with smaller antennas (RainCube’s deployable antenna measures at just half a yard, or meter, across) and allow an exponential increase in data transfer over long distances -- making RainCube a demonstration in improved communications as well. JPL developed the RainCube instrument, while Tyvak Inc. developed the spacecraft.

CubeSats can also be used to test new subsystems and techniques for improving data collection from space. Radio frequency interference (RFI) is a growing problem for space-based microwave radiometers, instruments important for studying soil moisture, meteorology, climate and other Earth properties.  As the number of RFI-causing devices -- including cell phones, radios, and televisions -- increases, it will be even more difficult for NASA’s satellite microwave radiometers to collect high-quality data.


Image above: The CubeRRT satellite and Blue Canyon Technologies team members with Principal Investigator Joel Johnson (far left) of The Ohio State University. Image Credits: Credit: Blue Canyon Technologies.

To address this issue, NASA’s InVEST program funded a team led by Joel Johnson of The Ohio State University to develop CubeRRT, the CubeSat Radiometer Radio Frequency Interference Technology Validation mission. “Our technology,” said Johnson, “will make it so that our Earth-observing radiometers can still continue to operate in the presence of this interference.”

RFI already affects data collected by Earth-observing satellites. To mitigate this problem, measurements are transmitted to the ground where they are then processed to remove any RFI-corrupted data. It is a complicated process and requires more data to be transmitted to Earth. With future satellites encountering even more RFI, more data could be corrupted and missions might not be able to meet their science goals.

Johnson collaborated with technologists at JPL and Goddard Space Flight Center, Greenbelt, Maryland, to develop the CubeRRT satellite to demonstrate the ability to detect RFI and filter out RFI-corrupted data in real time aboard the spacecraft. The spacecraft was developed by Blue Canyon Technologies, Boulder, Colorado.

One of the radiometer-collected weather measurements important to researchers involves cloud processes, specifically storm development and the identification of the time when rain begins to fall. Currently, weather satellites pass over storms just once every three hours, not frequently enough to identify many of the changes in dynamic storm systems. But the development of a new, extremely-compact radiometer system could change that.


Image above: The RainCube 6U CubeSat with fully-deployed antenna. Image Credits: Credit: NASA/JPL-Caltech.

NASA’s Earth System Science Pathfinder program selected Steven Reising of Colorado State University and partners at JPL to develop, build, and demonstrate a five-frequency radiometer based on newly available low-noise amplifier technologies developed with support from ESTO. The TEMPEST-D (Temporal Experiment for Storms and Tropical Systems Demonstration) mission will validate the miniaturized radiometer technology and demonstrate the spacecraft’s ability to perform drag maneuvers to control TEMPEST-D’s low-Earth altitude and its position in orbit. The instrument fits into a Blue Canyon Technologies 6U CubeSat -- the same size CubeSat as RainCube and CubeRRT.

“With a train-like constellation of TEMPEST-like CubeSats, we’d be able to take time samples every five to 10 minutes to see how a storm develops,” said Reising. This would improve upon the three-hour satellite revisit time, especially when collecting data on tropical storms like hurricanes that can quickly intensify and change.

RainCube, CubeRRT and TEMPEST-D are currently integrated aboard Orbital ATK’s Cygnus spacecraft and are awaiting launch on an Antares rocket.  After the CubeSats have arrived at the station, they will be deployed into low-Earth orbit and will begin their missions to test these new technologies useful for predicting weather, ensuring data quality, and helping researchers better understand storms.

Related articles:

Science Launching to Space Station Looks Forward and Back
http://orbiterchspacenews.blogspot.ch/2018/05/science-launching-to-space-station.html

Related links:

Earth Science Technology Office (ESTO): https://esto.nasa.gov/

RainCube: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7547

CubeRRT: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7360

TEMPEST-D: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7546

CubeSats: http://www.nasa.gov/cubesats/

Small Satellite Missions: http://www.nasa.gov/mission_pages/smallsats

Commercial Resupply: http://www.nasa.gov/mission_pages/station/structure/launch/index.html

Images (mentioned), Text, Credits: NASA/Steve Cole/Jon Nelson/Earth Science Technology Office/Andrea Martin/JPL/Esprit Smith/Alan Buis.

Greetings, Orbiter.ch

jeudi 17 mai 2018

New Views of Sun: 2 Missions Will Go Closer to Our Star Than Ever Before












NASA PARKER Solar Probe patch.

May 17, 2018

As we develop more and more powerful tools to peer beyond our solar system, we learn more about the seemingly endless sea of faraway stars and their curious casts of orbiting planets. But there’s only one star we can travel to directly and observe up close — and that’s our own: the Sun.

Two upcoming missions will soon take us closer to the Sun than we’ve ever been before, providing our best chance yet at uncovering the complexities of solar activity in our own solar system and shedding light on the very nature of space and stars throughout the universe. 

Together, NASA’s Parker Solar Probe and ESA’s (the European Space Agency) Solar Orbiter may resolve decades-old questions about the inner workings of our nearest star. Their comprehensive, up-close study of the Sun has important implications for how we live and explore: Energy from the Sun powers life on Earth, but it also triggers space weather events that can pose hazard to technology we increasingly depend upon. Such space weather can disrupt radio communications, affect satellites and human spaceflight, and — at its worst — interfere with power grids. A better understanding of the fundamental processes at the Sun driving these events could improve predictions of when they’ll occur and how their effects may be felt on Earth.

“Our goal is to understand how the Sun works and how it affects the space environment to the point of predictability,” said Chris St. Cyr, Solar Orbiter project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This is really a curiosity-driven science.”

Parker Solar Probe is slated to launch in the summer of 2018, and Solar Orbiter is scheduled to follow in 2020. These missions were developed independently, but their coordinated science objectives are no coincidence: Parker Solar Probe and Solar Orbiter are natural teammates.

Parker Solar Probe

Video above: Parker Solar Probe will swoop to within 4 million miles of the Sun's surface, facing heat and radiation like no spacecraft before it. Launching in 2018, Parker Solar Probe will provide new data on solar activity and may make critical contributions to our ability to forecast major space-weather events that affect life on Earth. Video Credits: NASA/Johns Hopkins APL.

Studying the solar corona

Both missions will take a closer look at the Sun's dynamic outer atmosphere, called the corona.  From Earth, the corona is visible only during total solar eclipses, when the Moon blocks the Sun's most intense light and reveals the outer atmosphere’s wispy, pearly-white structure. But the corona isn’t as delicate as it looks during a total solar eclipse — much of the corona’s behavior is unpredictable and not well understood.

The corona’s charged gases are driven by a set of laws of physics that are rarely involved with our normal experience on Earth. Teasing out the details of what causes the charged particles and magnetic fields to dance and twist as they do can help us understand two outstanding mysteries: what makes the corona so much hotter than the solar surface, and what drives the constant outpouring of solar material, the solar wind, to such high speeds.

We can see that corona from afar, and even measure what the solar wind looks like as it passes by Earth — but that’s like measuring a calm river miles downstream from a waterfall and trying to understand the current’s source. Only recently have we had the technology capable of withstanding the heat and radiation near the Sun, so for the first time, we’re going close to the source.


Image above: Illustration of the Parker Solar Probe spacecraft approaching the Sun. Image Credits: Johns Hopkins University Applied Physics Laboratory.

“Parker Solar Probe and Solar Orbiter employ different sorts of technology, but — as missions — they’ll be complementary,” said Eric Christian, a research scientist on the Parker Solar Probe mission at NASA Goddard. “They’ll be taking pictures of the Sun’s corona at the same time, and they’ll be seeing some of the same structures — what's happening at the poles of the Sun and what those same structures look like at the equator.”

Parker Solar Probe will traverse entirely new territory as it gets closer to the Sun than any spacecraft has come before — as close as 3.8 million miles from the solar surface. If Earth were scaled down to sit at one end of a football field, and the Sun at the other, the mission would make it to the 4-yard line. The current record holder, Helios B, a solar mission of the late 1970s, made it only to the 29-yard line.

From that vantage point, Parker Solar Probe’s four suites of scientific instruments are designed to image the solar wind and study magnetic fields, plasma and energetic particles — clarifying the true anatomy of the Sun’s outer atmosphere. This information will shed light on the so-called coronal heating problem. This refers to the counterintuitive reality that, while temperatures in the corona can spike upwards of a few million degrees Fahrenheit, the underlying solar surface, the photosphere, hovers around just 10,000 degrees. To fully appreciate the oddity of this temperature difference, imagine walking away from a campfire and feeling the air around you get much, much hotter.

Solar Orbiter will come within 26 million miles of the Sun — that would put it within the 27-yard line on that metaphorical football field. It will be in a highly tilted orbit that can provide our first-ever direct images of the Sun’s poles — parts of the Sun that we don’t yet understand well, and which may hold the key to understanding what drives our star’s constant activity and eruptions.


Image above: The NASA/ESA Solar Orbiter will capture the very first images of the Sun’s polar regions, where magnetic tension builds up and releases in a lively dance. Launching in 2020, Solar Orbiter’s study of the Sun will shed light on its magnetic structure and the many forces that shape solar activity. Image Credits: Spacecraft: ESA/ATG medialab; Sun: NASA/SDO/P. Testa (CfA).

Both Parker Solar Probe and Solar Orbiter will study the Sun’s most pervasive influence on the solar system: the solar wind. The Sun constantly exhales a stream of magnetized gas that fills the inner solar system, called solar wind. This solar wind interacts with magnetic fields, atmospheres, or even surfaces of worlds throughout the solar system. On Earth, this interaction can spark auroras and sometimes disrupt communications systems and power grids.

Data from previous missions have led scientists to believe the corona contributes to the processes that accelerate particles, driving the solar wind’s incredible speeds — which triple as it leaves the Sun and passes through the corona. Right now, the solar wind travels some 92 million miles by the time it reaches the spacecraft that measure it — plenty of time for this stream of charged gases to intermix with other particles traveling through space and lose some of its defining features. Parker Solar Probe will catch the solar wind just as it forms and leaves the corona, sending back to Earth some of the most pristine measurements of solar wind ever recorded. Solar Orbiter’s perspective, which will provide a good look at the Sun’s poles, will complement Parker Solar Probe’s study of the solar wind, because it allows scientists to see how the structure and behavior of the solar wind varies at different latitudes.

Solar Orbiter will also make use of its unique orbit to better understand the Sun’s magnetic fields; some of the Sun’s most interesting magnetic activity is concentrated at the poles. But because Earth orbits on a plane more or less in line with the solar equator, we don’t typically get a good view of the poles from afar. It’s a bit like trying to see the summit of Mount Everest from the base of the mountain.

Heliospheric Future: Solar Probe Plus & Solar Orbiter

Video above: Parker Solar Probe (formerly Solar Probe Plus) will move in a highly elliptical orbit, using seven gravity assists from Venus to move it closer to the Sun with each pass. Solar Orbiter will use Earth and Venus gravity assists to move into a relatively circular orbit and climb up and out of the ecliptic plane to capture the first images of the Sun’s poles. Video Credits: NASA’s Goddard Space Flight Center’s Scientific Visualization Studio; Tom Bridgman, lead animator; Scott Wiessinger, producer.

That view of the poles will also go a long way toward understanding the overall nature of the Sun’s magnetic field, which is lively and extensive, stretching far beyond the orbit of Neptune. The Sun’s magnetic field is so far-reaching largely because of the solar wind: As the solar wind streams outward, it carries the Sun’s magnetic field with it, creating a vast bubble, called the heliosphere. Within the heliosphere, the solar wind determines the very nature of planetary atmospheres. The heliosphere’s boundaries are shaped by how the Sun interacts with interstellar space. Since Voyager 1’s passage through the heliopause in 2012, we know these boundaries dramatically protect the inner solar system from incoming galactic radiation.

It’s not yet clear how exactly the Sun’s magnetic field is generated or structured deep inside the Sun — though we do know intense magnetic fields around the poles drives variability on the Sun, causing solar flares and coronal mass ejections. Solar Orbiter will hover over roughly the same region of the solar atmosphere for several days at a time while scientists watch tension build up and release around the poles. Those observations may lead to better awareness of the physical processes that ultimately generate the Sun’s magnetic field.

Together, Parker Solar Probe and Solar Orbiter will refine our knowledge of the Sun and heliosphere. Along the way, it’s likely these missions will pose even more questions than they answer — a problem scientists are very much looking forward to.

"There are questions that have been bugging us for a long time," said Adam Szabo, mission scientist for Parker Solar Probe at NASA Goddard. "We are trying to decipher what happens near the Sun, and the obvious solution is to just go there. We cannot wait — not just me, but the whole community."

Related links:

Parker Solar Probe Mission Overview: https://www.nasa.gov/content/goddard/parker-solar-probe-humanity-s-first-visit-to-a-star

Solar Storms FAQ: https://www.nasa.gov/mission_pages/sunearth/spaceweather/index.html

Parker Solar Probe: https://www.nasa.gov/solarprobe

Solar Orbiter: http://sci.esa.int/solar-orbiter/

Images (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Micheala Sosby.

Greetings, Orbiter.ch

Astronomers Release Most Complete Ultraviolet-Light Survey of Nearby Galaxies












NASA - Hubble Space Telescope patch.

May 17, 2018

Capitalizing on the unparalleled sharpness and spectral range of NASA's Hubble Space Telescope, an international team of astronomers is releasing the most comprehensive, high-resolution ultraviolet-light survey of nearby star-forming galaxies.

The researchers combined new Hubble observations with archival Hubble images for 50 star-forming spiral and dwarf galaxies in the local universe, offering a large and extensive resource for understanding the complexities of star formation and galaxy evolution. The project, called the Legacy ExtraGalactic UV Survey (LEGUS), has amassed star catalogs for each of the LEGUS galaxies and cluster catalogs for 30 of the galaxies, as well as images of the galaxies themselves. The data provide detailed information on young, massive stars and star clusters, and how their environment affects their development.


Images above: These six images represent the variety of star-forming regions in nearby galaxies. The galaxies are part of the Hubble Space Telescope's Legacy ExtraGalactic UV Survey (LEGUS), the sharpest, most comprehensive ultraviolet-light survey of star-forming galaxies in the nearby universe. The six images consist of two dwarf galaxies (UGC 5340 and UGCA 281) and four large spiral galaxies (NGC 3368, NGC 3627, NGC 6744, and NGC 4258). The images are a blend of ultraviolet light and visible light from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys. Images Credits: NASA/ESA/LEGUS team.

"There has never before been a star cluster and a stellar catalog that included observations in ultraviolet light," explained survey leader Daniela Calzetti of the University of Massachusetts, Amherst. "Ultraviolet light is a major tracer of the youngest and hottest star populations, which astronomers need to derive the ages of stars and get a complete stellar history. The synergy of the two catalogs combined offers an unprecedented potential for understanding star formation."

How stars form is still a vexing question in astronomy. "Much of the light we get from the universe comes from stars, and yet we still don't understand many aspects of how stars form," said team member Elena Sabbi of the Space Telescope Science Institute in Baltimore, Maryland. "This is even key to our existence — we know life wouldn't be here if we didn’t have a star around."

The research team carefully selected the LEGUS targets from among 500 galaxies, compiled in ground-based surveys, located between 11 million and 58 million light-years from Earth. Team members chose the galaxies based on their mass, star-formation rate, and abundances of elements that are heavier than hydrogen and helium. The catalog of ultraviolet objects collected by NASA's Galaxy Evolution Explorer (GALEX) spacecraft also helped lay the path for the Hubble study.

The team used Hubble's Wide Field Camera 3 and the Advanced Camera for Surveys over a one-year period to snap visible- and ultraviolet-light images of the galaxies and their most massive young stars and star clusters. The researchers also added archival visible-light images to provide a complete picture.

The star cluster catalogs contain about 8,000 young clusters whose ages range from 1 million to roughly 500 million years old. These stellar groupings are as much as 10 times more massive than the largest clusters seen in our Milky Way galaxy.

The star catalogs comprise about 39 million stars that are at least five times more massive than our Sun. Stars in the visible-light images are between 1 million and several billion years old; the youngest stars, those between 1 million and 100 million years old, shine prominently in ultraviolet light.

The Hubble data provide all of the information to analyze these galaxies, the researchers explained. "We also are offering computer models to help astronomers interpret the data in the star and cluster catalogs," Sabbi said. "Researchers, for example, can investigate how star formation occurred in one specific galaxy or a set of galaxies. They can correlate the properties of the galaxies with their star formation. They can derive the star-formation history of the galaxies. The ultraviolet-light images may also help astronomers identify the progenitor stars of supernovas found in the data."

One of the key questions the survey may help astronomers answer is the connection between star formation and the major structures, such as spiral arms, that make up a galaxy.

"When we look at a spiral galaxy, we usually don't just see a random distribution of stars," Calzetti said. “It's a very orderly structure, whether it's spiral arms or rings, and that's particularly true with the youngest stellar populations. On the other hand, there are multiple competing theories to connect the individual stars in individual star clusters to these ordered structures.

"By seeing galaxies in very fine detail — the star clusters — while also showing the connection to the larger structures, we are trying to identify the physical parameters underlying this ordering of stellar populations within galaxies. Getting the final link between gas and star formation is key for understanding galaxy evolution."

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

Team member Linda Smith of the European Space Agency (ESA) and the Space Telescope Science Institute added: "We're looking at the effects of the environment, particularly with star clusters, and how their survival is linked to the environment around them."

The LEGUS survey will also help astronomers interpret views of galaxies in the distant universe, where the ultraviolet glow from young stars is stretched to infrared wavelengths due to the expansion of space. "The data in the star and cluster catalogs of these nearby galaxies will help pave the way for what we see with NASA's upcoming infrared observatory, the James Webb Space Telescope, developed in partnership with ESA and the Canadian Space Agency (CSA)," Sabbi said.

Webb observations would be complementary to the LEGUS views. The space observatory will penetrate dusty stellar cocoons to reveal the infrared glow of infant stars, which cannot be seen in visible- and ultraviolet-light images. "Webb will be able to see how star formation propagates over a galaxy," Sabbi continued. "If you have information on the gas properties, you can really connect the points and see where, when, and how star formation happens."

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

For more information about Hubble, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Legacy ExtraGalactic UV Survey (LEGUS): https://legus.stsci.edu/legus_survey.html

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Karl Hille/Goddard Space Flight Center/Claire Saravia/Space Telescope Science Institute/Donna Weaver/Ray Villard.

Best regards, Orbiter.ch

OneSpace, Chinese private company launched it's first rocket












OneSpace logo.

May 17, 2018

OneSpace first Chinese private OS-X rocket launch

OneSpace launched a rocket 40 kilometers (25 miles) into the air on May 17, the first such demonstration by a private company as China urges its aerospace industry to match space technology developed in the US.

The nine-meter-tall rocket, powered by a solid propellant motor rather than a liquid-fueled rocket engine, is called the OS-X, and is designed to carry 100 kg (50lbs) of payload into space. OneSpace founder and CEO Shu Chang says he hopes to launch as many as 10 small satellites a year once the vehicle can reach orbit, while developing larger rockets for bigger spacecraft.

OneSpace larger rocket project

Governments and businesses alike are ploughing money into small satellites; thanks to advances in chip and battery technology, they have the capacity to do what much larger spacecraft can at a fraction of the cost. An equally fierce competition has emerged to launch these satellites, with companies like Vector, Virgin Galactic, and Rocket Lab working to build the small rockets needed to launch them cheaply. Rocket Lab put its first satellites in orbit this year.

A OneSpace spokesperson told Quartz the firm had designed, built, and launched its rocket with less than 500 million yuan ($78 million) in private funding, but didn’t reveal the specific number or the source of the investment. That makes this a cheap and relatively fast development program. OneSpace did not say how much its rocket would cost, but competitors with similarly sized rockets predict prices of $5 to $6 million per flight.

OneSpace first rocket launch

The use of solid propellant, which requires a less complex design and manufacturing process, could reduce upfront costs and speed launches. But it could also prove uncompetitive if reusable rockets designed by SpaceX, Blue Origin, and others are successful at driving down the price of putting a satellite in orbit, or flexible liquid-fueled engines prove more attractive to potential customers.

How private is private?

While China’s space program offers commercial launches to orbit, international companies looking to purchase flights face restrictions about working with the space program there because it is seen as closely linked to the military. In 2017, China performed one commercial satellite mission; SpaceX launched 12, and Europe’s Arianespace launched nine.

Chinese aerospace engineers have been impressed by the reductions in cost and growing capability of private companies like SpaceX. OneSpace is one of a handful of Chinese firms aiming to learn from that success; others include Landspace and Linkspace. (Dear rocket makers around the world: more creative names, please.)

Artist's view of OneSpace OS-X rocket

But questions remain about their links to the government. Landspace told Quartz in 2016 that its technology included a flight-proven rocket motor, indicating a design previously flown by the Chinese space program. OneSpace was paid for this flight by the state-owned Aviation Industry Corporation of China, and named its test rocket “Chongqing Liangjiang Star” after a state-backed Chongqing Liangjiang Aviation Industry Investment Group, which co-invested in their manufacturing facility.

This isn’t unusual in the space world: Arianespace, Boeing, and Lockheed Martin, the largest Western space contractors, rely on government revenue. The Japanese and French governments have announced new funds to back space startups. Even SpaceX, an outlier in terms of its private-sector focus, needed development funding from NASA and the US military to launch its first rockets, though they were entirely designed in-house.

The real question is whether OneSpace’s technology will be competitive enough to stand on its own in the world market. “Many compare us to SpaceX but to be honest, the gap is more than a little,” Shu told CNN.

For more information about OneSpace, visit: http://www.onespacechina.com/

Images, Animation, Text, Credits: Quartz/Tim Fernholz/OneSpace/Wan Nan/Chongqing Ribao.

Greetings, Orbiter.ch

Satellites Reveal Major Shifts in Global Freshwater











NASA & DLR - GRACE Mission patch.

May 17, 2018

In a first-of-its-kind study, scientists have combined an array of NASA satellite observations of Earth with data on human activities to map locations where freshwater is changing around the globe and to determine why.

The study, published Wednesday in the journal Nature, finds that Earth’s wet land areas are getting wetter and dry areas are getting drier due to a variety of factors, including human water management, climate change and natural cycles.


Animation above: This map depicts a time series of data collected by NASA's Gravity Recovery and Climate Experiment (GRACE) mission from 2002 to 2016, showing where freshwater storage was higher (blue) or lower (red) than the average for the 14-year study period. Animation Credit: NASA.

A team led by Matt Rodell of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, used 14 years of observations from the U.S./German-led Gravity Recovery and Climate Experiment (GRACE) spacecraft mission to track global trends in freshwater in 34 regions around the world. To understand why these trends emerged, they needed to pull in satellite precipitation data from the Global Precipitation Climatology Project, NASA/U.S. Geological Survey Landsat imagery, irrigation maps, and published reports of human activities related to agriculture, mining and reservoir operations. Only through analysis of the combined data sets were the scientists able to get a full understanding of the reasons for Earth’s freshwater changes as well as the sizes of those trends.

"This is the first time that we’ve used observations from multiple satellites in a thorough assessment of how freshwater availability is changing, everywhere on Earth," said Rodell. "A key goal was to distinguish shifts in terrestrial water storage caused by natural variability – wet periods and dry periods associated with El Niño and La Niña, for example – from trends related to climate change or human impacts, like pumping groundwater out of an aquifer faster than it is replenished."

Freshwater is found in lakes, rivers, soil, snow, groundwater and ice. Freshwater loss from the ice sheets at the poles – attributed to climate change – has implications for sea level rise. On land, freshwater is one of the most essential of Earth's resources, for drinking water and agriculture. While some regions' water supplies are relatively stable, others experienced increases or decreases.

"What we are witnessing is major hydrologic change," said co-author Jay Famiglietti of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "We see a distinctive pattern of the wet land areas of the world getting wetter – those are the high latitudes and the tropics – and the dry areas in between getting dryer. Embedded within the dry areas we see multiple hotspots resulting from groundwater depletion."

Famiglietti noted that while water loss in some regions, like the melting ice sheets and alpine glaciers, is clearly driven by warming climate, it will require more time and data to determine the driving forces behind other patterns of freshwater change.

"The pattern of wet-getting-wetter, dry-getting-drier during the rest of the 21st century is predicted by the Intergovernmental Panel on Climate Change models, but we’ll need a much longer dataset to be able to definitively say whether climate change is responsible for the emergence of any similar pattern in the GRACE data," he said.

The twin GRACE satellites, launched in 2002 as a joint mission with the German Aerospace Center (DLR), precisely measured the distance between the two spacecraft to detect changes in Earth's gravity field caused by movements of mass on the planet below. Using this method, GRACE tracked monthly variations in terrestrial water storage until its science mission ended in October 2017.

For 15 Years, GRACE Tracked Freshwater Movements Around the World

Video above: Between 2002 and 2016, NASA's Gravity Recovery and Climate Experiment (GRACE) tracked the movement of freshwater around the planet. Video Credits: NASA/Katy Mersmann.

However, the GRACE satellite observations alone couldn’t tell Rodell, Famiglietti and their colleagues what was causing the apparent trends.

"We examined information on precipitation, agriculture and groundwater pumping to find a possible explanation for the trends estimated from GRACE," said co-author Hiroko Beaudoing of Goddard and the University of Maryland in College Park.

For instance, although pumping groundwater for agricultural uses is a significant contributor to freshwater depletion throughout the world, groundwater levels are also sensitive to cycles of persistent drought or rainy conditions. Famiglietti noted that such a combination was likely the cause of the significant groundwater depletion observed in California’s Central Valley from 2007 to 2015, when decreased groundwater replenishment from rain and snowfall combined with increased pumping for agriculture.

Southwestern California lost 4 gigatons of freshwater per year during the same period. A gigaton of water would fill 400,000 Olympic swimming pools. A majority of California's freshwater comes in the form of rainfall and snow that collect in the Sierra Nevada snowpack and then is managed as it melts into surface waters through a series of reservoirs. When natural cycles led to less precipitation and caused diminished snowpack and surface waters, people relied on groundwater more heavily.

Downward trends in freshwater seen in Saudi Arabia also reflect agricultural pressures. From 2002 to 2016, the region lost 6.1 gigatons per year of stored groundwater. Imagery from Landsat satellites shows an explosive growth of irrigated farmland in the arid landscape from 1987 to the present, which may explain the increased drawdown.


Image above: Artist's view of U.S./German-led Gravity Recovery and Climate Experiment (GRACE) spacecrafts. Image Credits: NASA/DLR.

The team’s analyses also identified large, decade-long trends in terrestrial freshwater storage that do not appear to be directly related to human activities. Natural cycles of high or low rainfall can cause a trend that is unlikely to persist, Rodell said. An example is Africa’s western Zambezi basin and Okavango Delta, a vital watering hole for wildlife in northern Botswana. In this region, water storage increased at an average rate of 29 gigatons per year from 2002 to 2016. This wet period during the GRACE mission followed at least two decades of dryness. Rodell believes it is a case of natural variability that occurs over decades in this region of Africa.

The researchers found that a combination of natural and human pressures can lead to complex scenarios in some regions. Xinjiang province in northwestern China, about the size of Kansas, is bordered by Kazakhstan to the west and the Taklamakan desert to the south and encompasses the central portion of the Tien Shan Mountains. During the first decades of this century, previously undocumented water declines occurred in Xinjiang.

Rodell and his colleagues pieced together multiple factors to explain the loss of 5.5 gigatons of terrestrial water storage per year in Xinjiang province. Less rainfall was not the culprit. Additions to surface water were also occurring from climate change-induced glacier melt, and the pumping of groundwater out of coal mines. But these additions were more than offset by depletions caused by an increase in water consumption by irrigated cropland and evaporation of river water from the desert floor.

The successor to GRACE, called GRACE Follow-On, a joint mission with the German Research Centre for Geosciences (GFZ), currently is at Vandenberg Air Force Base in California undergoing final preparations for launch no earlier than May 22.

For more information on how NASA studies Earth, visit: https://www.nasa.gov/earth

GRACE (Gravity Recovery And Climate Experiment): http://www.nasa.gov/mission_pages/Grace/index.html

GRACE Follow-On (GRACE-FO): https://www.nasa.gov/missions/grace-fo

Image (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Steve Cole/Karen Northon.

Greetings, Orbiter.ch

mercredi 16 mai 2018

Veteran Astronauts Conclude Spacewalk for Thermal Maintenance














ISS - Expedition 55 Mission patch/ EVA - Extra Vehicular Activities patch.

May 16, 2018


Image above: NASA astronauts Ricky Arnold (left) and Drew Feustel (right) are pictured inside their U.S. spacesuits for a fit check verification ahead of a pair of spacewalks. Norishige Kanai (center), from the Japan Aerospace Exploration Agency, assisted the duo in and out of the spacesuits during the sizing process. Image Credit: NASA.

Feustel is wearing the suit bearing the red stripes, and Arnold’s suit has no stripes. Views from a camera on Feustel’s helmet are designated with the number 17, and Arnold’s is labeled with the number 18. Feustel is designated extravehicular crew member 1 (EV1) for this spacewalk, the eighth of his career. Arnold, embarking on his fourth spacewalk, is extravehicular crew member 2 (EV2).

Expedition 55 Flight Engineers Drew Feustel and Ricky Arnold of NASA completed the fifth spacewalk of this year at 2:10 p.m. EDT, lasting 6 hours, 31 minutes. The two astronauts moved the Pump Flow Control Subassembly (PFCS) from a spare parts platform on the station’s truss to the Dextre robotic arm. The PFCS drives and controls the flow of ammonia through the exterior portions of the station’s cooling system. The team then removed and replaced a camera group and a degraded Space to Ground Transmitter Receiver Controller, and was also able to complete several get-ahead tasks.


Image above: The Earth passes 250 miles below spacewalker Ricky Arnold today while he is attached to the tip of the Canadarm2 robotic arm in the middle of swapping television camera gear. Image Credit: NASA TV.

Spacewalkers have now spent a total of 54 days, 16 hours and 40 minutes working outside the station in support of assembly and maintenance of the orbiting laboratory.

Related links:

Expedition 55: https://www.nasa.gov/mission_pages/station/expeditions/expedition55/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

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

Best regards, Orbiter.ch

ALMA and VLT Find Evidence for Stars Forming Just 250 Million Years After Big Bang












ALMA - Atacama Large Millimeter/submillimeter Array logo.

16 May 2018

Hubble and ALMA image of MACS J1149.5+2223

Astronomers have used observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and ESO’s Very Large Telescope (VLT) to determine that star formation in the very distant galaxy MACS1149-JD1 started at an unexpectedly early stage, only 250 million years after the Big Bang. This discovery also represents the most distant oxygen ever detected in the Universe and the most distant galaxy ever observed by ALMA or the VLT. The results will appear in the journal Nature on 17 May 2018.

An international team of astronomers used ALMA to observe a distant galaxy called MACS1149-JD1. They detected a very faint glow emitted by ionised oxygen in the galaxy. As this infrared light travelled across space, the expansion of the Universe stretched it to wavelengths more than ten times longer by the time it reached Earth and was detected by ALMA. The team inferred that the signal was emitted 13.3 billion years ago (or 500 million years after the Big Bang), making it the most distant oxygen ever detected by any telescope [1]. The presence of oxygen is a clear sign that there must have been even earlier generations of stars in this galaxy.

Galaxy cluster MACS j1149.5+223

“I was thrilled to see the signal of the distant oxygen in the ALMA data,” says Takuya Hashimoto, the lead author of the new paper and a researcher at both Osaka Sangyo University and the National Astronomical Observatory of Japan. “This detection pushes back the frontiers of the observable Universe.”

In addition to the glow from oxygen picked up by ALMA, a weaker signal of hydrogen emission was also detected by ESO’s Very Large Telescope (VLT). The distance to the galaxy determined from this observation is consistent with the distance from the oxygen observation. This makes MACS1149-JD1 the most distant galaxy with a precise distance measurement and the most distant galaxy ever observed with ALMA or the VLT.

ALMA observation of distant galaxy MACS 1149-JD1

“This galaxy is seen at a time when the Universe was only 500 million years old and yet it already has a population of mature stars,” explains Nicolas Laporte, a researcher at University College London (UCL) in the UK and second author of the new paper. “We are therefore able to use this galaxy to probe into an earlier, completely uncharted period of cosmic history.”

For a period after the Big Bang there was no oxygen in the Universe; it was created by the fusion processes of the first stars and then released when these stars died. The detection of oxygen in MACS1149-JD1 indicates that these earlier generations of stars had been already formed and expelled oxygen by just 500 million years after the beginning of the Universe.

Zooming in on the distant galaxy MACS 1149-JD1

But when did this earlier star formation occur? To find out, the team reconstructed the earlier history of MACS1149-JD1 using infrared data taken with the NASA/ESA Hubble Space Telescope and the NASA Spitzer Space Telescope. They found that the observed brightness of the galaxy is well-explained by a model where the onset of star formation corresponds to only 250 million years after the Universe began [2].

The maturity of the stars seen in MACS1149-JD1 raises the question of when the very first galaxies emerged from total darkness, an epoch astronomers romantically term “cosmic dawn”. By establishing the age of MACS1149-JD1, the team has effectively demonstrated that galaxies existed earlier than those we can currently directly detect.

Computer simulation of star formation in MACS1149-JD1

Richard Ellis, senior astronomer at UCL and co-author of the paper, concludes: “Determining when cosmic dawn occurred is akin to the Holy Grail of cosmology and galaxy formation. With these new observations of MACS1149-JD1 we are getting closer to directly witnessing the birth of starlight! Since we are all made of processed stellar material, this is really finding our own origins.”

Zooming in on the distant galaxy MACS1149, and beyond

Notes:

[1] ALMA has set the record for detecting the most distant oxygen several times. In 2016, Akio Inoue at Osaka Sangyo University and his colleagues used ALMA to find a signal of oxygen emitted 13.1 billion years ago. Several months later, Nicolas Laporte of University College London used ALMA to detect oxygen 13.2 billion years ago. Now, the two teams combined their efforts and achieved this new record, which corresponds to a redshift of 9.1.

[2] This corresponds to a redshift of about 15.

More information:

These results are published in a paper entitled: “The onset of star formation 250 million years after the Big Bang”, by T. Hashimoto et al., to appear in the journal Nature on 17 May 2018.

The research team members are: Takuya Hashimoto (Osaka Sangyo University/National Astronomical Observatory of Japan, Japan), Nicolas Laporte (University College London, United Kingdom), Ken Mawatari (Osaka Sangyo University, Japan), Richard S. Ellis (University College London, United Kingdom), Akio. K. Inoue (Osaka Sangyo University, Japan), Erik Zackrisson (Uppsala University, Sweden), Guido Roberts-Borsani (University College London, United Kingdom), Wei Zheng (Johns Hopkins University, Baltimore, Maryland, United States), Yoichi Tamura (Nagoya University, Japan), Franz E. Bauer (Pontificia Universidad Católica de Chile, Santiago, Chile), Thomas Fletcher (University College London, United Kingdom), Yuichi Harikane (The University of Tokyo, Japan), Bunyo Hatsukade (The University of Tokyo, Japan), Natsuki H. Hayatsu (The University of Tokyo, Japan; ESO, Garching, Germany), Yuichi Matsuda (National Astronomical Observatory of Japan/SOKENDAI, Japan), Hiroshi Matsuo (National Astronomical Observatory of Japan/SOKENDAI, Japan, Sapporo, Japan), Takashi Okamoto (Hokkaido University, Sapporo, Japan), Masami Ouchi (The University of Tokyo, Japan), Roser Pelló (Université de Toulouse, France), Claes-Erik Rydberg (Universität Heidelberg, Germany), Ikkoh Shimizu (Osaka University, Japan), Yoshiaki Taniguchi (The Open University of Japan, Chiba, Japan), Hideki Umehata (The University of Tokyo, Japan) and Naoki Yoshida (The University of Tokyo, Japan).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 15 Member States: Austria, Belgium, 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 and with Australia as a strategic partner. 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 and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESOcast 161 Light: Distant galaxy reveals very early star formation: https://www.eso.org/public/videos/eso1815a/

Research paper in Nature: http://www.eso.org/public/archives/releases/sciencepapers/eso1815/eso1815a.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Very%20Large%20Telescope

Photos of ALMA: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Atacama%20Large%20Millimeter/submillimeter%20Array

ESO’s Very Large Telescope (VLT): http://www.eso.org/public/teles-instr/paranal-observatory/vlt/

Atacama Large Millimeter/submillimeter Array (ALMA): http://eso.org/alma

NASA/ESA Hubble Space Telescope: https://www.spacetelescope.org/

NASA Spitzer Space Telescope: https://www.nasa.gov/mission_pages/spitzer/main/index.html

Osaka Sangyo University: http://www.osaka-sandai.ac.jp/english/

National Astronomical Observatory of Japan: https://www.nao.ac.jp/en/

Images, Text, Credits: ESO/Richard Hook/University College London/Richard Ellis/University College London/Nicolas Laporte/ALMA (ESO/NAOJ/NRAO), NASA/ESA Hubble Space Telescope, W. Zheng (JHU), M. Postman (STScI), the CLASH Team, Hashimoto et al./redit:/NASA, ESA, S. Rodney (John Hopkins University, USA) and the FrontierSN team; T. Treu (University of California Los Angeles, USA), P. Kelly (University of California Berkeley, USA) and the GLASS team; J. Lotz (STScI) and the Frontier Fields team; M. Postman (STScI) and the CLASH team; and Z. Levay (STScI)/ALMA (ESO/NAOJ/NRAO), Hashimoto et al./Videos: ESO, ALMA (ESO/NAOJ/NRAO), N. Risinger (skysurvey.org). Music: Konstantino Polizois/NASA/ESA Hubble Space Telescope, W. Zheng (JHU), M. Postman (STScI), the CLASH Team, Hashimoto et al.

Greetings, Orbiter.ch

A space ant fires its lasers












ESA - Herschel Mission patch.

16 May 2018

A rare phenomenon connected to the death of a star has been discovered in observations made by ESA’s Herschel space observatory: an unusual laser emission from the spectacular Ant Nebula, which suggests the presence of a double star system hidden at its heart.

When low- to middleweight stars like our Sun approach the end of their lives they eventually become dense, white dwarf stars. In the process, they cast off their outer layers of gas and dust into space, creating a kaleidoscope of intricate patterns known as a planetary nebula.

Ant Nebula

The infrared Herschel observations have shown that the dramatic demise of the central star in the core of the Ant Nebula is even more theatrical than implied by its colourful appearance in visible images – such as those taken by the NASA/ESA Hubble Space Telescope. As revealed by the new data, the Ant Nebula also beams intense laser emission from its core.

While lasers in everyday life today might mean special visual effects in music concerts, in space, focused emission is detected at different wavelengths under specific conditions. Only a few of these space infrared lasers are known.

Stellar evolution

By coincidence, astronomer Donald Menzel who first observed and classified this particular planetary nebula in the 1920s (it is officially known as Menzel 3 after him) was also one of the first to suggest that in certain conditions natural ‘light amplification by stimulated emission of radiation’ – from which the acronym ‘laser’ derives – could occur in gaseous nebulae. This was well before the discovery and first successful operation of lasers in laboratories in 1960, an occasion which is now celebrated annually on 16 May as International Day of Light.

“When we observe Menzel 3, we see an amazingly intricate structure made up of ionized gas, but we cannot see the object in its centre producing this pattern,” says Isabel Aleman, lead author of a paper describing the new results.

“Thanks to the sensitivity and wide wavelength range of the Herschel observatory, we detected a very rare type of emission called hydrogen recombination line laser emission, which provided a way to reveal the nebula’s structure and physical conditions.”

Herschel infrared observatory

This kind of laser emission needs very dense gas close to the star. Comparison of the observations with models found that the density of the laser-emitting gas is around ten thousand times higher than that of the gas seen in typical planetary nebulae and in the lobes of the Ant Nebula itself.

Normally, the region close to the dead star – close in this case being about the distance of Saturn from the Sun – is quite empty, because most of its material is ejected outwards. Any lingering gas would soon fall back onto it.

“The only way to keep gas close to the star is if it is orbiting around it in a disc,” says co-author Albert Zijlstra. “In this case, we have actually observed a dense disc in the very centre that is seen approximately edge-on. This orientation helps to amplify the laser signal. The disc suggests the white dwarf has a binary companion, because it is hard to get the ejected gas to go into orbit unless a companion star deflects it in the right direction.”

Herschel in the cleanroom

Astronomers have not yet seen the expected second star, but they think that the mass from the dying companion star is being ejected and then captured by the compact central star of the original planetary nebula, producing the disc where the laser emission is produced.

“We used Herschel to characterise various components of gas and dust in nebula around old stars, but we were not necessarily looking for a laser phenomenon,” adds Toshiya Ueta, principal investigator of the Herschel Planetary Nebula Survey project. “Such emission has only been identified in a handful of objects before; this was a remarkable discovery that we did not anticipate. There is certainly more to stellar nebulae than meets the eye!”

“This study suggests that the distinctive Ant Nebula as we see it today was created by the complex nature of a binary star system, which influences the shape, chemical properties, and evolution in these final stages of a star’s life,” says Göran Pilbratt, ESA’s Herschel project scientist.

“Herschel offered the perfect observing capabilities to detect this extraordinary laser in the Ant Nebula. The findings will help constrain the conditions under which this phenomenon occurs, and help us to refine our models of stellar evolution. It is also a happy conclusion that the Herschel mission was able to connect together Menzel’s two discoveries from almost a century ago.”

Notes for editors:

“Herschel Planetary Nebula Survey (HerPlaNS): Hydrogen Recombination Laser Lines in Mz 3” by I. Aleman et al is accepted for publication in Monthly Notices of the Royal Astronomical Society: https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/sty966/4996370

The Herschel space observatory operated between 2009 and 2013.

Herschel: ESA's giant infrared observatory: http://www.esa.int/Our_Activities/Space_Science/Herschel

Herschel overview: http://www.esa.int/Our_Activities/Space_Science/Herschel_overview

Herschel on YouTube:

Inside Herschel: http://www.youtube.com/watch?v=j9_VBKn8Jq4&feature=PlayList&p=CD471914889C152B&index=1

Herschel mission objectives: http://www.youtube.com/watch?v=YyEpV1_CH4w&feature=PlayList&p=CD471914889C152B&index=5

Images, Text, Credits: ESA/Markus Bauer/Göran Pilbratt/University of Manchester/University of Hong Kong/Albert Zijlstra/University of Denver/Toshiya Ueta/University of Sao Paulo/Isabel Aleman/NASA, ESA and the Hubble Heritage Team (STScI/AURA).

Best regards, Orbiter.ch