mercredi 24 août 2016
NASA - WISE Mission logo / NASA - Fermi Gamma-ray Space Telescope logo.
Aug. 24, 2016
Astronomers studying distant galaxies powered by monster black holes have uncovered an unexpected link between two very different wavelengths of the light they emit, the mid-infrared and gamma rays. The discovery, which was accomplished by comparing data from NASA’s Wide-field Infrared Survey Explorer (WISE) and Fermi Gamma-ray Space Telescope, has enabled the researchers to uncover dozens of new blazar candidates.
Francesco Massaro at the University of Turin in Italy and Raffaele D’Abrusco at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, show for the first time that the mid-infrared colors of blazars in WISE data correlate to an equivalent measurement of their gamma-ray output.
"This connection links two vastly different forms of light over an energy range spanning a factor of 10 billion," said Massaro. "Ultimately, it will help us decipher how supermassive black holes in these galaxies manage to convert the matter around them into vast amounts of energy."
Graphic above: An analysis of blazar properties observed by the Wide-field Infrared Survey Explorer (WISE) and Fermi's Large Area Telescope (LAT) reveal a correlation in emissions from the mid-infrared to gamma rays, an energy range spanning a factor of 10 billion. When plotted by gamma-ray and mid-infrared colors, confirmed Fermi blazars (gold dots) form a unique band not shared by other sources beyond our galaxy. A blue line marks the best fit of these values. The relationship allows astronomers to identify potential new gamma-ray blazars by studying WISE infrared data. Graphic Credits: NASA's Goddard Space Flight Center/Francesco Massaro, University of Turin.
Blazars constitute more than half of the discrete gamma-ray sources seen by Fermi's Large Area Telescope (LAT). At the heart of a blazar lies a supersized black hole with millions of times the sun's mass surrounded by a disk of hot gas and dust. As material in the disk falls toward the black hole, some of it forms dual jets that blast subatomic particles straight out of the disk in opposite directions at nearly the speed of light. A blazar appears bright to Fermi for two reasons. Its jets produce many gamma rays, the highest-energy form of light, and we happen to be viewing the galaxy face on, which means one of its jets is pointing in our direction.
From January to August 2010, NASA's WISE mapped the entire sky in four infrared wavelengths, cataloging more than half a billion sources. In 2011, Massaro, D’Abrusco and their colleagues began using WISE data to investigate Fermi blazars.
"WISE made it possible to explore the mid-infrared colors of known gamma-ray blazars," said D’Abrusco. "We found that when we plotted Fermi blazars by their WISE colors in a particular way, they occupied a distinctly different part of the plot than other extragalactic gamma-ray sources."
The scientists detail new aspects of the infrared/gamma-ray connection in a paper published in The Astrophysical Journal on Aug. 9. They say the electrons, protons and other particles accelerated in blazar jets leave a specific "fingerprint" in the infrared light they emit. This same pattern is also clearly evident in their gamma rays. The relationship effectively connects the dots for blazars across an enormous swath of the electromagnetic spectrum.
Image above: Black-hole-powered galaxies called blazars are the most common sources detected by NASA's Fermi Gamma-ray Space Telescope. As matter falls toward the supermassive black hole at the galaxy's center, some of it is accelerated outward at nearly the speed of light along jets pointed in opposite directions. When one of the jets happens to be aimed in the direction of Earth, as illustrated here, the galaxy appears especially bright and is classified as a blazar. Image Credits: M. Weiss/CfA.
About a thousand Fermi sources remain unassociated with known objects at any other wavelength. Astronomers suspect many of these are blazars, but there isn't enough information to classify them. The infrared/gamma-ray connection led the authors to search for new blazar candidates among WISE infrared sources located within the positional uncertainties of Fermi's unidentified gamma-ray objects. When the researchers applied this relationship to Fermi's unknown sources, they quickly found 130 potential blazars. Efforts are now under way to confirm the nature of these objects through follow-up studies and to search for additional candidates using the WISE connection.
"About a third of the gamma-ray objects seen by Fermi remained unknown in the most recent catalog, and this result represents an important advance in understanding their natures," said David Thompson, a Fermi deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
NASA's Jet Propulsion Laboratory in Pasadena, California, manages and operates WISE for NASA's Science Mission Directorate in Washington. The spacecraft was put into hibernation mode in 2011 after twice scanning the entire sky, thereby completing its main objectives. In September 2013, WISE was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify potentially hazardous near-Earth objects.
NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.
For more information on Fermi, visit: http://www.nasa.gov/fermi
For more information on WISE, visit: http://www.nasa.gov/wise
Image and Graphic (mentioned), Text, Credits: NASA/Ashley Morrow/JPL/Elizabeth Landau/NASA's Goddard Space Flight Center, by Francis Reddy.
Publié par Orbiter.ch à 18:32
ISS - Expedition 48 Mission patch.
Aug. 24, 2016
You don’t have to go to Rio to see Americans breaking records – you can find one orbiting 250 miles above Earth.
On Wednesday, Aug. 24, NASA astronaut and Expedition 48 Commander Jeff Williams surpassed 520 days living in space, breaking Scott Kelly’s previous record for most cumulative time spent in space by a U.S. astronaut, set during Kelly’s year-long mission.
Scott Kelly Congratulates Jeff Williams on Breaking Record
Video above: Former astronaut Scott Kelly called space station Commander Jeff Williams from Mission Control Center to congratulate him for establishing a new NASA astronaut record for cumulative time in space. Video Credit: NASA.
By the time Williams returns home on Sept. 6, he’ll leave us with a new total of 534 days.
The first 10 of Williams’ 520 days were spent on Space Shuttle Atlantis during STS-101 in 2000, back when the International Space Station was still under construction. As a flight engineer and spacewalker for the mission, he helped prepare the space station for its first crew, which arrived less than five months later. At that point, the space station consisted of just the Zarya module and the Unity node.
When Williams returned in 2006 for his first long duration stay as part of Expedition 13, the space station had grown significantly. The Russian Zvezda service module, the U.S. Destiny laboratory and the Quest airlock all had been installed in the intervening years, as well as several segments of the station’s backbone and solar arrays. In addition, the science experiments that the orbiting laboratory was built for were already going on, with subjects ranging from capillary flow to the effects of microgravity on astronauts’ central nervous systems. And Williams was able to add two additional spacewalks to his resume, setting up additional experiments on the exterior of the station and replacing equipment.
Image above: Astronaut Jeff WIlliams in pictured in 2006 when he was a crew member during Expedition 13. Image Credit: NASA.
After six months at the space station, Williams returned to Earth and waited three years for another visit. He returned in 2009 for his first stint commanding the space station. While he was away, the station continued to grow, adding the Harmony node, the European Columbus laboratory and the Japanese Kibo laboratory. And over the course of his stay for Expedition 21/22, he saw the arrival of the Poisk Russian Mini Research Module and two space shuttle missions, one of which delivered Tranquility node and the space station cupola.
Williams began his current visit to the station with more than 362 days in space. He launched to the station from the Baikonur Cosmodrome in Kazakhstan on March 18, and kicked off his third long-duration mission as part of Expedition 47/48. Since his last visit, the space station had been declared complete, but he’s still finding some construction work to do – he was on board for the arrival and deployment of the Bigelow Expandable Activity Module, and took part in Friday’s spacewalk to add the international docking adapter that will allow future commercial crew vehicles to dock to the station.
When he leaves the station again, the 534 days that Williams will have racked up will earn him the 14th spot on the all-time endurance list for astronauts and cosmonauts, in addition to the top ranking for U.S. astronauts. But he won’t hold on to the position for long – Peggy Whitson is scheduled to surpass him in 2017 during her next mission, which launches in November.
International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html
Expedition 48: https://www.nasa.gov/mission_pages/station/expeditions/expedition48/index.html
Image (mentioned), Video (mentioned), Text, Credits: NASA/Mark Garcia.
Publié par Orbiter.ch à 18:18
NASA - Voyager 1 & 2 Mission patch.
Aug. 24, 2016
Saturn, with its alluring rings and numerous moons, has long fascinated stargazers and scientists. After an initial flyby of Pioneer 11 in 1979, humanity got a second, much closer look at this complex planetary system in the early 1980s through the eyes of NASA's twin Voyager spacecraft.
Image above: Up-close views from the Voyagers, like this one from Voyager 2, showed Saturn and its rings as never before. Image Credits: NASA/JPL-Caltech.
Voyager 2 made its closest approach to Saturn 35 years ago -- on Aug. 25, 1981. What the Voyagers revealed at the planet was so phenomenal that, just one year later, a joint American and European working group began discussing a mission that would carry on Voyager's legacy at Saturn. That mission -- named Cassini -- has been studying the Saturn system since 2004. Cassini has followed up on many of Voyager's discoveries, and has deepened our understanding of what some might call a "mini solar system."
"Saturn, like all of the planets the Voyagers visited, was full of exciting discoveries and surprises," said Ed Stone, Voyager project scientist at Caltech in Pasadena, California. "By giving us unprecedented views of the Saturn system, Voyager gave us plenty of reasons to go back for a closer look."
Many Mysterious Moons
Voyager's Saturn flybys provided a thrilling look at the planet's moons -- a diverse menagerie of worlds, each with unique character and charm. Voyager's images transformed the moons from points of light to fully realized places. Dramatic landscapes on Tethys, Dione, Rhea, Iapetus and other moons tantalized scientists with features hinting at tortured pasts.
"The stars of the Saturn system are the moons, which surprised all of us on both the Voyager and Cassini missions," said Linda Spilker, project scientist for Cassini at NASA's Jet Propulsion Laboratory, Pasadena. Spilker also served on the Voyager science team.
Image above: Titan was a high priority for the Voyager flybys at Saturn. The two spacecraft saw tantalizing hints of the structure and composition of the giant moon's dense atmosphere. Image Credits: NASA/JPL-Caltech.
One of the key findings of the Voyagers' visits to Saturn was that the planet's moons had evidence of past geological activity and that Enceladus -- the brightest, most reflective planetary body scientists had ever seen -- could still be active.
Cassini set out to delve deeper into the nature of these moons, and found that, indeed, icy Enceladus has geysers erupting to this day. Cassini also confirmed that Enceladus is the source of Saturn's E ring, which was suggested by Voyager. But while Voyager images of wispy terrain hinted at ice volcanoes on Dione, Cassini found this feathery coating was actually a system of bright canyons.
Titan, Saturn's largest moon, was a high-priority target for the Voyager mission. Gerard Kuiper, for whom the Kuiper Belt is named, had discovered in 1944 that Titan had an atmosphere containing methane. Observations from both Voyagers showed that Titan's atmosphere was primarily composed of nitrogen, with a few percent methane and smaller amounts of other complex hydrocarbons, such as ethane, propane and acetylene. No other moon in the solar system has a dense atmosphere.
Mission planners mapped out a path through the Saturn system that provided the gravitational boost needed to send Voyager 2 onward to Uranus. But because of intense interest in Titan's atmosphere, the giant moon was the higher priority. In fact, the team would have directed Voyager 2 much closer to Titan if Voyager 1 had not been successful in observing it.
Image above: This psychedelic false-color view of Saturn from Voyager 2 reveals structure in the planet's banded clouds. Image Credits: NASA/JPL-Caltech.
"To fly close to Titan, Voyager 2 would have swung upward out of the plane of the planets, and couldn't have gone on to visit any others," Stone said. "It was fortunate that Voyager 1's observations of Titan went flawlessly, so that Voyager 2 could continue traveling to Uranus and Neptune."
To the Voyagers, Titan appeared as a featureless orange ball because of dense haze in its atmosphere. Seeing through this haze was a chief goal of the Cassini mission. Cassini carried cameras with infrared vision that could see through the haze, a radar that could map the surface in detail, and the European Huygens probe, which landed on the moon's frigid surface on Jan. 14, 2005. We now know, thanks to Cassini, that smoggy Titan has methane lakes and flooded canyons.
New Shapes and Sizes
Voyager discovered four new moons and sharpened our view of some that were previously known. The spacecraft also revealed how the gravitational pull of these satellites causes ripples in Saturn's rings, much like the wake of a ship on the sea. There were also surprising gaps in the rings, some caused by moons embedded within them.
Voyager also revealed an immense hexagonal feature in the clouds that surrounded Saturn's north pole, which Cassini found was still going strong a quarter century later. Additionally, Voyager measured the wind speeds, temperature and density of Saturn's atmosphere. With Voyager's measurements as a starting point, Cassini further explored how Saturn's atmosphere changes with the seasons.
Lingering Mysteries of Saturn and Beyond
While both missions have vastly improved our understanding of Saturn, its rings and moons, there are still mysteries galore. For example, the exact length of Saturn's day continues to elude researchers. The Voyagers measured it to be a period of 10.66 hours, but Cassini has measured two different, changing periods in the north and south.
Image above: Voyager 2 saw hints that Enceladus might be active, but the icy moon held onto its secrets until the arrival of the Cassini mission. Image Credits: NASA/JPL-Caltech.
Voyager also made the first up-close observations of Saturn's rings, discovering new thin and faint rings, along with the ghostly features called spokes. But despite more than a decade of observations with Cassini, scientists are still unsure about the age of the rings -- they could be hundreds of millions of years old, or several billion. Cassini, in turn, has prompted new questions of its own, such as whether the ocean worlds Enceladus and Titan could be habitable.
"The twin Voyagers rewrote the textbooks on Saturn, its rings and moons, and we couldn't wait to go back with Cassini," Spilker said. "New mysteries uncovered by Cassini will await the next missions to follow in the footsteps of Voyager."
Voyager 2’s mission of discovery continues to this day. It is now part of the Heliophysics System Observatory, a collection of missions that explore our space environment, and which contribute to protecting future missions on their journeys. Voyager now explores what's known as the interstellar boundary region, where material blowing out from the sun encounters similar winds from other stars.
The two Voyager spacecraft, as well as Cassini, were built by JPL, which continues to operate the three missions. JPL is a division of Caltech. For more information about the Voyager spacecraft, visit:
Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL, written by Elizabeth Landau and Preston Dyches.
Publié par Orbiter.ch à 18:10
ARIANESPACE - Ariane 5 ECA / Flight VA232 Mission poster.
Aug 24, 2016
Arianespace has successfully launched the Intelsat 33e and Intelsat 36 satellites for Intel-sat, the world’s leading provider of satellite services. VA232 was the first Ariane 5 dual launch entirely dedicated to Intelsat satellites.
Image above: Ariane 5 during its rollout to the Spaceport’s ELA-3 launch zone. Flight VA232. Intelsat 33e and Intelsat 36. Image Credit: Arianespace.
Arianespace’s sixth launch of 2016, the fourth using an Ariane 5, took place on Wednes-day, August 24, 2016 at 07:16 p.m. (local time) from the Guiana Space Center in Kourou, French Guiana. This mission was the 73rd successful Ariane 5 launch in a row. It also reflected Ariane 5’s steadily increasing performance, as the heavy launcher set a new record by lofting 10,735 kg. into geostationary transfer orbit (GTO), outpacing the previ-ous record of 10,730 kg., set in June 2016.
Today’s launch was Arianespace’s second of the year for Intelsat. Arianespace has now launched 58 satellites for this operator, further strengthening a partnership that spans more than three decades.
Arianespace and Intelsat: partners for more than 30 years
Intelsat is the world’s leading provider of satellite services in terms of revenue and in-orbit capacity, with a fleet of approximately 50 satellites. It delivers high-performance distribution solutions for media applications and high data-rate connectivity for enterprise, fixed and mobile telecommunications and government applications.
Intelsat 33e and Intelsat 36 are the company’s 57th and 58th satellites launched by Arianespace since the orbiting of Intelsat 507 in October 1983.
Arianespace has now launched the first two satellites in the Intelsat EpicNG series:
- Intelsat 29e, launched in January 2016, covers the Americas and the North Atlantic.
- Intelsat 33e, the second satellite in this series, will provide broadband coverage of Europe, the Middle East, Africa and the Asia-Pacific, as well as certain media solutions.
The Intelsat 36 satellite will provide media distribution services for the south African and Indian Ocean regions.
Since being founded, Arianespace has launched half of all Intelsat satellites, including half of its current in-orbit fleet of operational satellites.
In 2017, Arianespace will launch two other Intelsat satellites: Intelsat 32e and Intelsat 37e.
A fruitful collaboration with satellite manufacturers Boeing and SSL
Ariane 5 ECA / Intelsat 33e & 36 / Flight VA232 Mission poster
Arianespace and Boeing have been partners since 1987. Intelsat 33e is the 52nd Boeing satellite to be launched by Arianespace, which has four more Boeing satellites in its order book.
Arianespace and SSL have been working together since 1983. With Intelsat 36, Arianespace has now launched 56 satellites based on SSL platforms, and has nine more SSL satellites in its order book, including five to be deployed in GTO.
A strong presence in the United States
Arianespace opened an office in Washington, D.C. in 1986 and has clearly established its position as a major player in the United States.
The launch services provider now has five geostationary (GEO) satellites in its order book for U.S.-based operators, along with 12 geostationary satellites built by American manufacturers.
Arianespace also will deploy telecommunications and Earth observation constellations built in the United States.
Arianespace in the United States
- Present for 30 years in the U.S., via Arianespace, Inc., the Washington, D.C.-based Arianespace subsidiary.
- 87 GEO and 69 non-GEO satellites launched for American operators.
- 177 satellites launched by Arianespace were built by American manufacturers.
- Nearly half of the GEO satellites orbited for American operators have been launched by Arianespace.
Additionally, Arianespace will use an Ariane 5 in October 2018 to launch the James Webb Space Telescope (JWST), developed by NASA in conjunction with the Canadian Space Agency and European Space Agency (ESA).
Intelsat 33e was built by Boeing using a Boeing-702MP platform. Intelsat 33e had a liftoff mass of 6,600 kg., and offers a design life exceeding 15 years. Positioned at 60° East, it is fitted with 249 Ku-band and 20 C-band transponders. Coverage zone: Europe, Middle East, Africa and Asia-Pacific.
Intelsat 36 was built by SSL using a 1300 platform. Intelsat 36 had a liftoff mass of 3,253 kg., and offers a design life exceeding 15 years. Positioned at 68.5° East, it is fitted with 10 C-band and 34 Ku-band transponders. Coverage zone: Southern Africa and the Indian Ocean.
The launch at a glance
Shortly after the announcement of the orbital injection of the two satellites on today’s Flight VA232 with Ariane 5, Arianespace Chairman and Chief Executive Officer Stéphane Israël said: “Two more! I would like to extend my warmest thanks to Intelsat for honoring us with their loyalty over the last 30-plus years, and for choosing us for to-day’s first-ever launch of two of their telecom satellites on the same Ariane 5. Following the successful launch of Intelsat 29e in January, we are very proud of having earned their trust. I would also like to thank our two long-standing partners, Boeing and SSL, who built the two Intelsat satellites we launched on this mission. My congratula-tions go to everybody who contributed to this 73rd successful launch in a row of Ariane 5: Airbus Safran Launchers and the entire European launcher industry for the reliability and availability of Ariane 5, which confirms its excep-tional performance improvement with today’s launch; ESA, for its seamless support for the Ariane program; the CNES/CSG, and all companies and staff at the launch base, who continue to support us as we go from success to success; and of course the teams at Arianespace, for their commitment and professionalism, as we mark our sixth successful launch in 2016 and gear up for five more launches during the year.”
To use space for a better life on earth, Arianespace guarantees access to space transportation services and solu-tions for any type of satellite, commercial as well as institutional, into any orbit. Since 1980, Arianespace has placed more than 500 satellites into orbit with its three launchers, Ariane, Soyuz and Vega, from French Gui-ana in South America, and from Baikonur, Kazakhstan (central Asia). Arianespace is headquartered in Evry, France near Paris, and has a facility at the Guiana Space Center in French Guiana, plus local offices in Washington, D.C., Tokyo and Singapore.
For more information about Arianespace, visit: http://www.arianespace.com/
Images, Video, Text, Credits: ARIANESPACE/Intelsat/Günter Space Page.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 17:24
ESO - European Southern Observatory logo.
24 August 2016
Pale Red Dot campaign reveals Earth-mass world in orbit around Proxima Centauri
Artist's impression of the planet orbiting Proxima Centauri
Astronomers using ESO telescopes and other facilities have found clear evidence of a planet orbiting the closest star to Earth, Proxima Centauri. The long-sought world, designated Proxima b, orbits its cool red parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than the Earth and is the closest exoplanet to us — and it may also be the closest possible abode for life outside the Solar System. A paper describing this milestone finding will be published in the journal Nature on 25 August 2016.
The location of Proxima Centauri in the southern skies
Just over four light-years from the Solar System lies a red dwarf star that has been named Proxima Centauri as it is the closest star to Earth apart from the Sun. This cool star in the constellation of Centaurus is too faint to be seen with the unaided eye and lies near to the much brighter pair of stars known as Alpha Centauri AB.
Proxima Centauri and its planet compared to the Solar System
During the first half of 2016 Proxima Centauri was regularly observed with the HARPS spectrograph on the ESO 3.6-metre telescope at La Silla in Chile and simultaneously monitored by other telescopes around the world . This was the Pale Red Dot campaign, in which a team of astronomers led by Guillem Anglada-Escudé, from Queen Mary University of London, was looking for the tiny back and forth wobble of the star that would be caused by the gravitational pull of a possible orbiting planet .
The motion of Proxima Centauri in 2016, revealing the fingerprints of a planet
As this was a topic with very wide public interest, the progress of the campaign between mid-January and April 2016 was shared publicly as it happened on the Pale Red Dot website and via social media. The reports were accompanied by numerous outreach articles written by specialists around the world.
Artist's impression of the planet orbiting Proxima Centauri
Guillem Anglada-Escudé explains the background to this unique search: “The first hints of a possible planet were spotted back in 2013, but the detection was not convincing. Since then we have worked hard to get further observations off the ground with help from ESO and others. The recent Pale Red Dot campaign has been about two years in the planning.”
The sky around Alpha Centauri and Proxima Centauri (annotated)
The Pale Red Dot data, when combined with earlier observations made at ESO observatories and elsewhere, revealed the clear signal of a truly exciting result. At times Proxima Centauri is approaching Earth at about 5 kilometres per hour — normal human walking pace — and at times receding at the same speed. This regular pattern of changing radial velocities repeats with a period of 11.2 days. Careful analysis of the resulting tiny Doppler shifts showed that they indicated the presence of a planet with a mass at least 1.3 times that of the Earth, orbiting about 7 million kilometres from Proxima Centauri — only 5% of the Earth-Sun distance .
Proxima Centauri in the southern constellation of Centaurus
Guillem Anglada-Escudé comments on the excitement of the last few months: "I kept checking the consistency of the signal every single day during the 60 nights of the Pale Red Dot campaign. The first 10 were promising, the first 20 were consistent with expectations, and at 30 days the result was pretty much definitive, so we started drafting the paper!"
Relative Sizes of the Alpha Centauri Components and other Objects (artist’s impression)
Red dwarfs like Proxima Centauri are active stars and can vary in ways that would mimic the presence of a planet. To exclude this possibility the team also monitored the changing brightness of the star very carefully during the campaign using the ASH2 telescope at the San Pedro de Atacama Celestial Explorations Observatory in Chile and the Las Cumbres Observatory telescope network. Radial velocity data taken when the star was flaring were excluded from the final analysis.
The sky around Alpha Centauri and Proxima Centauri
Although Proxima b orbits much closer to its star than Mercury does to the Sun in the Solar System, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone around the star and has an estimated surface temperature that would allow the presence of liquid water. Despite the temperate orbit of Proxima b, the conditions on the surface may be strongly affected by the ultraviolet and X-ray flares from the star — far more intense than the Earth experiences from the Sun .
Artist's impression of the planet orbiting Proxima Centauri (annotated)
Two separate papers discuss the habitability of Proxima b and its climate. They find that the existence of liquid water on the planet today cannot be ruled out and, in such case, it may be present over the surface of the planet only in the sunniest regions, either in an area in the hemisphere of the planet facing the star (synchronous rotation) or in a tropical belt (3:2 resonance rotation). Proxima b's rotation, the strong radiation from its star and the formation history of the planet makes its climate quite different from that of the Earth, and it is unlikely that Proxima b has seasons.
Angular apparent size comparison
This discovery will be the beginning of extensive further observations, both with current instruments  and with the next generation of giant telescopes such as the European Extremely Large Telescope (E-ELT). Proxima b will be a prime target for the hunt for evidence of life elsewhere in the Universe. Indeed, the Alpha Centauri system is also the target of humankind’s first attempt to travel to another star system, the StarShot project.
The brilliant southern Milky Way
Guillem Anglada-Escudé concludes: "Many exoplanets have been found and many more will be found, but searching for the closest potential Earth-analogue and succeeding has been the experience of a lifetime for all of us. Many people’s stories and efforts have converged on this discovery. The result is also a tribute to all of them. The search for life on Proxima b comes next..."
The Pale Red Dot Campaign
Artist's impression of the planet orbiting Proxima Centauri
Artist's impression of the planet orbiting Proxima Centauri
A journey to Proxima Centauri and its planet
A fly-through of the Proxima Centauri system
A fly-through of the Proxima Centauri system
 Besides data from the recent Pale Red Dot campaign, the paper incorporates contributions from scientists who have been observing Proxima Centauri for many years. These include members of the original UVES/ESO M-dwarf programme (Martin Kürster and Michael Endl), and exoplanet search pioneers such as R. Paul Butler. Public observations from the HARPS/Geneva team obtained over many years were also included.
 The name Pale Red Dot reflects Carl Sagan’s famous reference to the Earth as a pale blue dot. As Proxima Centauri is a red dwarf star it will bathe its orbiting planet in a pale red glow.
 The detection reported today has been technically possible for the last 10 years. In fact, signals with smaller amplitudes have been detected previously. However, stars are not smooth balls of gas and Proxima Centauri is an active star. The robust detection of Proxima b has only been possible after reaching a detailed understanding of how the star changes on timescales from minutes to a decade, and monitoring its brightness with photometric telescopes.
 The actual suitability of this kind of planet to support water and Earth-like life is a matter of intense but mostly theoretical debate. Major concerns that count against the presence of life are related to the closeness of the star. For example gravitational forces probably lock the same side of the planet in perpetual daylight, while the other side is in perpetual night. The planet's atmosphere might also slowly be evaporating or have more complex chemistry than Earth’s due to stronger ultraviolet and X-ray radiation, especially during the first billion years of the star’s life. However, none of the arguments has been proven conclusively and they are unlikely to be settled without direct observational evidence and characterisation of the planet’s atmosphere. Similar factors apply to the planets recently found around TRAPPIST-1.
 Some methods to study a planet’s atmosphere depend on it passing in front of its star and the starlight passing through the atmosphere on its way to Earth. Currently there is no evidence that Proxima b transits across the disc of its parent star, and the chances of this happening seem small, but further observations to check this possibility are in progress.
This research is presented in a paper entitled “A terrestrial planet candidate in a temperate orbit around Proxima Centauri”, by G. Anglada-Escudé et al., to appear in the journal Nature on 25 August 2016.
The team is composed of Guillem Anglada-Escudé (Queen Mary University of London, London, UK), Pedro J. Amado (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), John Barnes (Open University, Milton Keynes, UK), Zaira M. Berdiñas (Instituto de Astrofísica de Andalucia - CSIC, Granada, Spain), R. Paul Butler (Carnegie Institution of Washington, Department of Terrestrial Magnetism, Washington, USA), Gavin A. L. Coleman (Queen Mary University of London, London, UK), Ignacio de la Cueva (Astroimagen, Ibiza, Spain), Stefan Dreizler (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Michael Endl (The University of Texas at Austin and McDonald Observatory, Austin, Texas, USA), Benjamin Giesers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Sandra V. Jeffers (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), James S. Jenkins (Universidad de Chile, Santiago, Chile), Hugh R. A. Jones (University of Hertfordshire, Hatfield, UK), Marcin Kiraga (Warsaw University Observatory, Warsaw, Poland), Martin Kürster (Max-Planck-Institut für Astronomie, Heidelberg, Germany), María J. López-González (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Christopher J. Marvin (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Nicolás Morales (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Julien Morin (Laboratoire Univers et Particules de Montpellier, Université de Montpellier & CNRS, Montpellier, France), Richard P. Nelson (Queen Mary University of London, London, UK), José L. Ortiz (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Aviv Ofir (Weizmann Institute of Science, Rehovot, Israel), Sijme-Jan Paardekooper (Queen Mary University of London, London, UK), Ansgar Reiners (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), Eloy Rodriguez (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Cristina Rodriguez-Lopez (Instituto de Astrofísica de Andalucía - CSIC, Granada, Spain), Luis F. Sarmiento (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany), John P. Strachan (Queen Mary University of London, London, UK), Yiannis Tsapras (Astronomisches Rechen-Institut, Heidelberg, Germany), Mikko Tuomi (University of Hertfordshire, Hatfield, UK) and Mathias Zechmeister (Institut für Astrophysik, Georg-August-Universität Göttingen, Göttingen, Germany).
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
ESOcast 87: Pale Red Dot Results: http://www.eso.org/public/videos/eso1629a/
Research paper in Nature: http://www.eso.org/public/archives/releases/sciencepapers/eso1629/eso1629a.pdf
ESO press conference (01:02:26): http://eso.adobeconnect.com/p3l3qqhq6un/
Two new papers on Habitability on Proxima b: http://www.proximacentauri.info/
Pale Red Dot blog: https://palereddot.org/
Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/
Photos of HARPS and the ESO 3.6-metre telescope: http://www.eso.org/public/images/archive/search/?adv=&subject_name=harps
Video of the ESO 3.6-metre telescope: http://www.eso.org/public/videos/archive/search/?adv=&subject_name=3.6
Photos of LCOGT telescopes: http://lcogt.net/images/observatory/
MPIA press release: http://www.mpia.de/News/Science-Releases/2016/2016-10-planet-proxima
LCOGT press release: https://lcogt.net/blog/proxima-centauri-b/
University of Hertfordshire press release: https://www.herts.ac.uk/about-us/news/2016/august/university-of-hertfordshire-astronomers-play-key-role-in-discovery-of-new-earth-like-planet
Laboratoire Univers et Particules de Montpellier press release: http://www.lupm.univ-montp2.fr/spip.php?article468
Additional images and videos from the PHL @ UPR Arecibo: http://phl.upr.edu/press-releases/proxb
University of Texas/McDonald Observatory press release: https://mcdonaldobservatory.org/news/releases/20160824
Images, Text, Credits: ESO/M. Kornmesser/Y. Beletsky (LCO)/ESO/ESA/NASA/M. Zamani/G. Coleman/G. Anglada-Escudé/Digitized Sky Survey 2/Acknowledgement: Davide De Martin/Mahdi Zamani/IAU and Sky & Telescope/G. Coleman/A. Fujii/Pale Red Dot/Videos: ESO/M. Kornmesser/L. Calçada/Nick Risinger (skysurvey.org)/PHL @ UPR Arecibo, ESO. Music by Lyford Rome.
Publié par Orbiter.ch à 14:15
CNSA - China National Space Administration logo.
August 24, 2016
China released the first images of synthesis of unmanned vehicle it plans to land on the Red Planet in 2020.
China's Mars 2020 lander using thrusters to land on the Martian surface
China, investing billions of euros in its ambitious space program to catch up on the United States and Europe, announced in April its intention to send such a "rover" to Mars.
Zhang Rongqiao, the chief designer of the project, said Tuesday targeting a launch for July or August 2020, according to the official Xinhua news agency. "The challenges are without precedent," he stressed, however.
China's Mars 2020 lander ready for the descent of the rover
A rocket "Long March-5" will be launched from the new no Chinese shooting Wenchang, in the island province of Hainan (South), the agency said, citing Ye Peijian, counselor of the mission. The lander will separate from the orbiter at the end of an Earth-Mars travel about seven months and is expected to land near the equator of Mars, where the vehicle should explore the Martian surface has Xinhua said.
200 kilos of technology
The "rover", weighing 200 kilos, will be equipped with six wheels and four solar panels, and should be operational for about 92 days, the source said. It will carry 13 facilities - including a remote sensing camera and radar - to study the composition of the soil, the environment and atmosphere, looking in particular water and ice tracks.
The rover will be equipped with six wheels and four solar panels
China's space program, a source of national pride and led by the army, is symbolic of the growing international status occupied by China. China's first lunar unmanned vehicle - the "Jade Rabbit" - was launched in late 2013, alternating on the Moon prowess, technical problems and resurrections before finally extinguished early August to the end of a life more long as hoped. However, China has so far mainly been content to repeat the exploits space already made by the United States and Europe.
Beijing has also been overtaken by India, in September 2014 became the first Asian country to reach Mars with a low-cost sensor placed in orbit around the red planet. The United States have already ask two unmanned vehicle on Mars, and ROSCOSMOS (Russia) and the European Space Agency (ESA) have also conducted missions to the planet. In 2011, China's first attempt to send a satellite into orbit around Mars had ended in failure.
For more information about China Space Program, visit:
http://www.cnsa.gov.cn/ and http://www.cnsa.gov.cn/n6443408/index.html
Images, Text, Credits: CNSA/NXP/AFP/Xinhua/Orbiter.ch Aerospace/Roland Berga.
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Publié par Orbiter.ch à 04:36
August 24, 2016
Image above: Jonathan Sauder's AREE rover had a fully mechanical computer and logic system, allowing it to function in the harsh Venusian landscape. Image Credits: ESA/J. Whatmore/NASA/JPL-Caltech.
Proposals Include Wind-Powered Automatons and Icy Volcano Divers
Each year, NASA funds a handful of futuristic concepts to push forward the boundaries of space exploration. These early-stage proposals are selected with the hope of developing new ideas into realistic proofs-of-concept. From Aug. 23 to 25, the NASA Innovative Advanced Concepts (NIAC) symposium will host presentations on 28 proposals, including five from NASA's Jet Propulsion Laboratory, Pasadena, California.
The 2016 NIAC Symposium will also be carried live via LiveStream at:
Most of JPL's proposals are Phase I concepts, which means they are little more than ideas right now. Their creators will have to deliver reports explaining each project's technical challenges in order to advance them to Phase II of funding. If they advance to Phase II, they would be awarded up to $500,000 for a two-year study to further develop the project.
"The NIAC program is designed to let technologists stretch and create concepts that have never been considered by NASA before," said Jason Derleth, NIAC program executive for NASA's Space Technology Mission Directorate. "Each proposal is still required to be based on solid scientific and engineering principles and to advance NASA's mission objectives."
These JPL proposals will be at the symposium:
A Solar Oasis in Lunar Craters
The advantage of solar power is its unlimited supply: the sun provides plenty of warmth and energy so long as you can access its rays. But what if a mission is to explore a permanently shaded lunar crater surrounded by tall mountain peaks? Or to venture into a cave, which could contain water ice and be habitable if not for the darkness and low temperatures?
Images above: Adrian Stoica's concept, now in Phase II, would use folding mirrors to reflect sunlight into craters or caves, creating a "solar oasis." Image Credits: Adrian Stoica/NASA/JPL-Caltech.
Adrian Stoica of JPL led a concept that has successfully advanced to Phase II: building mirrored "TransFormers," a new class of shape-changing robotic structures that unfold like origami and reflect solar energy wherever you need it. Phase I examined whether such a structure could power a single rover as it explores a crater. Phase II is more ambitious in scope: whether an entire solar infrastructure could create a "solar oasis" hosting fleets of rovers, equipment and even humans.
The Phase II proposal examines how to provide power and warmth for lunar bases, even colonies, which could support humans and robotic workers alike. TransFormers are projected to be more affordable and easier to transport than radioisotope thermoelectric generators (RTGs) like the one that powers NASA's Mars Science Laboratory. TransFormers could potentially allow a wider range of robots and equipment to function in crater sites, where they could extract water used to make fuel for affordable travels to Mars and beyond.
Art-inspired automata could reveal the interior of Venus
Venus' forbidding atmosphere has claimed numerous landers over the years. With temperatures of more than 842 degrees Fahrenheit (450 degrees Celsius), sulfuric acid clouds and crushing surface pressures, electronics won't last longer than a few hours in all but the most robust spacecraft.
Jonathan Sauder of JPL thinks the solution may be getting rid of the electronics altogether. Inspired by mechanical automata - including spider-like "Strandbeest" created by artist Theo Jansen -- Sauder's NIAC proposal is AREE, or Automaton Rover for Extreme Environments.
AREE's legs and science instruments would be controlled by a fully mechanical computer and powered by a wind turbine. Temperature, wind speed and seismic measurements could be "broadcast" by a rising and falling radar reflector "piston": the piston's up or down position could be read as Morse code by a radar tracker orbiting the planet. The orbiter would then relay the readings to Earth.
Journey to the center of an icy moon
Europa and Enceladus are fascinating subjects for a future planetary mission because of their potential for subsurface, habitable oceans. The question is how to break through each moon's icy crust and pilot a craft down below.
Images above: Masahiro Ono's concept: a robot could enter the subsurface oceans of a moon like Enceladus by rappelling into a cryovolcano. Image Credits: Masahiro Ono/NASA/JPL-Caltech.
Masahiro Ono of JPL wants to borrow a page from Jules Verne. In "Journey to the Center of the Earth," the characters venture into a volcano to explore the planet's inner world. Ono's proposal, the Icy-moon Cryovolcano Explorer (ICE), would include setting a lander down next to a cryovolcano, a vent that erupts with water vapor and small particles. A robot could then crawl to the edge and be lowered in by cable, like a rappelling alpinist.
The robot could analyze the inside of the vent and send science back to the lander, which would then relay its findings to Earth. The robot could eventually descend all the way to the subsurface ocean. There, it would release an autonomous underwater vehicle for further exploration.
Glide, don't land, to study an asteroid
There's intense interest in studying asteroids, but the challenge is getting near them. There isn't enough gravity or atmosphere to allow a spacecraft to touch down without ricocheting off the surface.
But why land when you can glide? JPLer Marco Quadrelli's Electrostatic Glider (E-Glider) was inspired by the idea of dust fountains visible on our moon's surface: when warmed by the sun, these dust particles gain an electrostatic charge. The same principle turns every asteroid or comet's dust into a weak but usable power supply.
Quadrelli's glider would be a low-cost craft attached to foil-like streamers. These streamers would inflate and lift based on the electrostatic energy around them. The glider could then be steered around an asteroid and perform basic science readings on its composition.
A Battery Recharger in the Skies of Venus
Another challenge of sending a craft to Venus is how to extend its power supply. Batteries will only last a few hours, and the thick Venusian atmosphere weakens the efficiency of solar power.
Ratnakumar Bugga of JPL has proposed a weather balloon powered by chemical batteries. The Venus Interior Probe Using In-Situ Power and Propulsion (VIP-INSPR) would use electrolysis to generate hydrogen from the thick Venus atmosphere. It could then store that power as chemical hydride in its fuel cells.
This battery system could effectively have an unlimited power supply, recharging as it lowered itself into the Venusian atmosphere to perform science readings.
The NIAC program, funded by NASA's Space Technology Mission Directorate, nurtures visionary ideas that could transform future NASA missions with the creation of breakthroughs - radically better or entirely new aerospace concepts -- while engaging America's innovators and entrepreneurs as partners in the journey. Caltech manages JPL for NASA.
AREE, or Automaton Rover for Extreme Environments: https://www.nasa.gov/feature/automaton-rover-for-extreme-environments-aree/
Icy-moon Cryovolcano Explorer (ICE): https://www.nasa.gov/feature/journey-to-the-center-of-icy-moons
Electrostatic Glider (E-Glider): https://www.nasa.gov/feature/e-glider-active-electrostatic-flight-for-airless-body-exploration
Venus Interior Probe Using In-Situ Power and Propulsion (VIP-INSPR): https://www.nasa.gov/feature/venus-interior-probe-using-in-situ-power-and-propulsion-vip-inspr
For more information about the NIAC symposium, visit:
For more information about NIAC, visit:
Images (mentioned), Text, Credits: NASA/JPL/Andrew Good.
Publié par Orbiter.ch à 03:41