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Space News Update — December 9, 2016 —

Contents

In the News

Story 1: NASA Remembers American Legend John Glenn

Story 2: Cassini Beams Back First Images from New Orbit

Story 3: ALMA Measures Size of Seeds of Planets

Departments

The Night Sky

ISS Sighting Opportunities

Space Calendar

NASA-TV Highlights

Food for Thought

Space Image of the Week

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1. NASA Remembers American Legend John Glenn

The following is a statement from NASA Administrator Charles Bolden on the passing of Sen. John Glenn:

“Today [Thursday, December 8 2016], the first American to orbit the Earth, NASA astronaut and Ohio Senator John Glenn, passed away. We mourn this tremendous loss for our nation and the world. As one of NASA's original Mercury 7 astronauts, Glenn's riveting flight aboard Friendship 7 on Feb. 20, 1962, united our nation, launched America to the forefront of the space race, and secured for him a unique place in the annals of history.

“While that first orbit was the experience of a lifetime, Glenn, who also had flown combat missions in both World War II and the Korean War as a Marine aviator, continued to serve his country as a four-term Senator from Ohio, as a trusted statesman, and an educator. In 1998, at the age of 77, he became the oldest human to venture into space as a crew member on the Discovery space shuttle -- once again advancing our understanding of living and working in space.

“He earned many honors for both his military and public service achievements. In 2012, President Obama awarded him the Presidential Medal of Freedom, the highest civilian honor the country can bestow, and he also received the Congressional Gold Medal.

“Glenn's extraordinary courage, intellect, patriotism and humanity were the hallmarks of a life of greatness. His missions have helped make possible everything our space program has since achieved and the human missions to an asteroid and Mars that we are striving toward now.

“With all his accomplishments, he was always focused on the young people of today, who would soon lead the world. ‘The most important thing we can do is inspire young minds and advance the kind of science, math and technology education that will help youngsters take us to the next phase of space travel,’ he said. ‘To me, there is no greater calling … If I can inspire young people to dedicate themselves to the good of mankind, I've accomplished something.’

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“Senator Glenn's legacy is one of risk and accomplishment, of history created and duty to country carried out under great pressure with the whole world watching. The entire NASA Family will be forever grateful for his outstanding service, commitment and friendship. Personally, I shall miss him greatly. As a fellow Marine and aviator, he was a mentor, role model and, most importantly, a dear friend. My prayers go out to his lovely and devoted wife, Annie, and the entire Glenn family at this time of their great loss."

For more information about Glenn’s NASA career, and his agency biography, visit:

http://www.nasa.gov/johnglenn

[Editor’s Note: For another summary of Glenn’s career, see http://spaceflightnow.com/2016/12/08/john-glenn-first-american-in-orbit-passes-away-at-95/]

Source: NASA Return to Contents

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2. Cassini Beams Back First Images from New Orbit

NASA's Cassini spacecraft has sent to Earth its first views of Saturn’s atmosphere since beginning the latest phase of its mission. The new images show scenes from high above Saturn's northern hemisphere, including the planet's intriguing hexagon-shaped jet stream.

Cassini began its new mission phase, called its Ring-Grazing Orbits, on Nov. 30. Each of these weeklong orbits -- 20 in all -- carries the spacecraft high above Saturn's northern hemisphere before sending it skimming past the outer edges of the planet's main rings.

Cassini’s imaging cameras acquired these latest views on Dec. 2 and 3, about two days before the first ring-grazing approach to the planet. Future passes will include images from near closest approach, including some of the closest-ever views of the outer rings and small moons that orbit there.

"This is it, the beginning of the end of our historic exploration of Saturn. Let these images -- and those

to come -- remind you that we’ve lived a bold and daring adventure around the solar system’s most magnificent planet," said Carolyn Porco, Cassini imaging team lead at Space Science Institute, Boulder, Colorado.

The next pass by the rings' outer edges is planned for Dec. 11. The ring-grazing orbits will continue until April 22, when the last close flyby of Saturn's moon Titan will once again reshape Cassini's flight path. With that encounter, Cassini will begin its Grand Finale, leaping over the rings and making the first of 22 plunges through the 1,500-mile-wide (2,400-kilometer) gap between Saturn and its innermost ring on April 26.

On Sept. 15, the mission's planned conclusion will be a final dive into Saturn's atmosphere. During its plunge, Cassini will transmit data about the atmosphere's composition until its signal is lost.

Launched in 1997, Cassini has been touring the Saturn system since arriving in 2004 for an up-close study of the planet, its rings and moons. Cassini has made numerous dramatic discoveries, including a global ocean with indications of hydrothermal activity within the moon Enceladus, and liquid methane seas on another moon, Titan.

For details about Cassini's ring-grazing orbits, visit:

https://saturn.jpl.nasa.gov/news/2966/ring-grazing-orbits

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. JPL designed, developed and assembled the Cassini orbiter.

More information about Cassini is at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

Source: NASA Return to Contents

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3. ALMA Measures Size of Seeds of Planets

Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) have, for the first time, achieved a precise size measurement of small dust particles around a young star through radio-wave polarization.

ALMA's high sensitivity for detecting polarized radio waves made possible this important step in tracing the formation of planets around young stars.

Astronomers have believed that planets are formed from gas and dust particles, although the details of the process have been veiled. One of the major enigmas is how dust particles as small as 1 micrometer aggregate to form a rocky planet with a diameter of 10 thousand kilometers. Difficulty in measuring the size of dust particles has prevented astronomers from tracing the process of dust growth.

Akimasa Kataoka, a Humboldt Research Fellow stationed at Heidelberg University and the National Astronomical Observatory of Japan, tackled this problem. He and his collaborators have theoretically predicted that, around a young star, radio waves scattered by the dust particles should carry unique polarization features. He also noticed that the intensity of polarized emissions allows us to estimate the size of dust particles far better than other methods.

To test their prediction, the team led by Kataoka observed the young star HD 142527 with ALMA and discovered, for the first time, the unique polarization pattern in the dust disk around the star. As predicted, the polarization has a radial direction in most parts of the disk, but at the edge of the disk, the direction is flipped perpendicular to the radial direction.

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Comparing the observed intensity of the polarized emissions with the theoretical prediction, they determined that the size of the dust particles is at most 150 micrometers. This is the first estimation of the dust size based on polarization. Surprisingly, this estimated size is more than 10 times smaller than previously thought.

"In the previous studies, astronomers have estimated the size based on radio emissions assuming hypothetical spherical dust particles," explains Kataoka. "In our study, we observed the scattered radio waves through polarization, which carries independent information from the thermal dust emission. Such a big difference in the estimated size of dust particles implies that the previous assumption might be wrong."

The team's idea to solve this inconsistency is to consider fluffy, complex-shaped dust particles, not simple spherical dust. In the macroscopic view, such particles are indeed large, but in the microscopic view, each small part of a large dust particle scatters radio waves and produces unique polarization features. According to the present study, astronomers obtain these "microscopic" features through polarization observations. This idea might prompt astronomers to reconsider the previous interpretation of observational data.

"The polarization fraction of radio waves from the dust disk around HD 142527 is only a few percent. Thanks to ALMA's high sensitivity, we have detected such a tiny signal to derive information about the size and shape of the dust particles," said Kataoka. "This is the very first step in the research on dust evolution with polarimetry, and I believe the future progress will be full of excitement."

Source: Spaceref.com Return to Contents

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The Night Sky

Friday, December 9

• Vega still glitters brightly in the northwest early these evenings. Deneb is the brightest star above it. Deneb is the head of the big Northern Cross, which now extends to Deneb's lower left. By about 10 p.m. the Northern Cross swings down and around to plant itself upright on the northwest horizon (as seen from mid-northern latitudes).

Saturday, December 10

• Right after dark you'll find the Pleiades high in the east, with Aldebaran and the Hyades below them. Far below these, Orion is beginning to clear the horizon. By about 9 p.m. Orion is much higher and Sirius is rising below it, completing this famous tall stack of December stars.

Sunday, December 11

• Watch for early Geminid meteors! The occasional Geminid should be flashing into view by now even through the moonlight. The shower is due to peak late Tuesday night December 13–14, as told below. On any night, rates increase through the evening and will be greatest from midnight to 4 a.m., when the radiant in Gemini is high overhead.

Monday, December 12

• The Moon, just a day before full, occults Aldebaran tonight for nearly everyone in North America — around the middle of the night in the East, and earlier in the evening for the West. In westernmost Europe, the occultation happens before dawn on the 13th. The bright orange star vanishes on the Moon's narrow dark limb just beyond the brilliantly sunlit landscape, so use a telescope and look up the exact time for your location.

Source: Sky & Telescope Return to Contents

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ISS Sighting Opportunities

For Denver: Date Visible Max Height Appears Disappears Fri Dec 9, 4:58 PM < 1 min 11° 11° above N 10° above NNE Sat Dec 10, 5:41 PM 1 min 10° 10° above NNW 10° above N Sun Dec 11, 6:26 PM < 1 min 10° 10° above NNW 10° above NNW Mon Dec 12, 5:34 PM 2 min 11° 10° above NNW 10° above NNE Tue Dec 13, 6:18 PM 1 min 15° 10° above NNW 15° above N Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Daylight Time)

Monday, December 12

6 a.m., NASA’s Cyclone Global Navigation Satellite System (CYGNSS) Spacecraft Prelaunch Program by NASA EDGE (all channels)

7 a.m., NASA’s Cyclone Global Navigation Satellite System (CYGNSS) Spacecraft Launch Coverage and Commentary (all channels)

2:30 p.m., Hidden Figures Panel Discussion (all channels)

Tuesday, December 13

4:30 a.m., Coverage of the Grapple of the JAXA “Kounotori” H-II Transfer Vehicle Cargo Ship (Capture is scheduled at appx. 6 a.m. ET) (all channels)

9 a.m., Coverage of the Installation of the JAXA “Kounotori” H-II Transfer Vehicle Cargo Ship to the ISS (starts at 9:15 a.m.) (all channels)

Watch NASA TV on the Net by going to the NASA website. Return to Contents

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Space Calendar • Dec 09 - [Dec 09] HTV 6 H-2B Launch (International Space Station), Successful • Dec 09 - [Dec 09] Apollo Asteroid 2016 XV17 Near-Earth Flyby (0.051 AU) • Dec 09 - Aten Asteroid 1994 XL1 Near-Earth Flyby (0.092 AU) • Dec 09 - Asteroid 8837 London Closest Approach To Earth (1.453 AU) • Dec 09 - Asteroid 15000 CCD Closest Approach To Earth (2.029 AU) • Dec 09 - Asteroid 1000 Piazzia Closest Approach To Earth (3.056 AU) • Dec 09 - Meeting: Frozen Worlds and Landscapes of our Solar System, London, United Kingdom • Dec 09 - Meeting: Radio Galaxies in the Local Universe, London, United Kingdom • Dec 09 - 10th Anniversary (2006), STS-116 Launch (Space Shuttle Discovery, International Space

Station) • Dec 09 - Steve Pravdo's 65th Birthday (1951) • Dec 09 - Henry Kendall's 90th Birthday (1926) • Dec 10 - Comet C/2014 OE4 (PANSTARRS) Perihelion (6.245 AU) • Dec 10 - Asteroid 3054 Strugatskia Occults HIP 29367 (6.8 Magnitude Star) • Dec 10 - Apollo Asteroid 2014 HM4 Near-Earth Flyby (0.060 AU) • Dec 10 - [Dec 04] Apollo Asteroid 2016 XF Near-Earth Flyby (0.069 AU) • Dec 10 - Asteroid 3693 Barringer Closest Approach To Earth (1.993 AU) • Dec 10 - Plutino 84922 (2003 VS2) At Opposition (35.638 AU) • Dec 10 - Plutino 307463 (2002 VU130) At Opposition (39.392 AU) • Dec 10 - Kuiper Belt Object 2004 XR190 At Opposition (56.394 AU) • Dec 11 - [Dec 09] Fengyun 4A CZ-3B Launch • Dec 11 - Juno, Period Reduction Maneuver (PRM) • Dec 11 - Cassini, Distant Flyby of Prometheus & Pallene • Dec 11 - Mercury At Its Greatest Eastern Elongation (21 Degrees) • Dec 11 - Comet 318P/McNaught-Hartley At Opposition (3.241 AU) • Dec 11 - Comet P/2005 L1 (McNaught) At Opposition (3.683 AU) • Dec 11 - Asteroid 96193 Edmonton Closest Approach To Earth (1.298 AU) • Dec 11 - Tsien Hsu-shen's 105th Birthday (1911) • Dec 12 - Cyclone Global Navigation Satellite System 1-8 (CYGNSS 1-8) Pegasus XL Launch • Dec 12 - Comet C/2016 U1 (NEOWISE) Closest Approach To Earth (0.709 AU) • Dec 12 - [Dec 04] Apollo Asteroid 2016 XA Near-Earth Flyby (0.018 AU) • Dec 12 - Atira Asteroid 2008 UL90 Near-Earth Flyby (0.039 AU) • Dec 12 - [Dec 09] Apollo Asteroid 2016 XA18 Near-Earth Flyby (0.051 AU) • Dec 12 - Asteroid 4457 van Gogh Closest Approach To Earth (1.680 AU) • Dec 12 - Asteroid 371 Bohemia Closest Approach To Earth (1.918 AU) • Dec 12 - Asteroid 1495 Helsinki Closest Approach To Earth (2.065 AU) • Dec 12 - 55th Anniversary (1961), Oscar 1 Launch

Oscar 1

Source: JPL Space Calendar Return to Contents

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Food for Thought

Home Computers Discover Record-Breaking Binary Neutron Star

Almost 25,000 light-years away, two dead stars, each more massive than our Sun, but only 20 kilometers in diameter, orbit one another in less than five hours.

This unusual pair of extreme objects, known as neutron stars, was discovered by an international team of scientists -- including researchers from the Max Planck Institute for Gravitational Physics and the Max Planck Institute for Radio Astronomy -- and by volunteers from the distributed computing project Einstein@Home. Their find is the latest addition to a short list of only 14 known similar binary systems, and it also is the most massive of those. Double neutron star systems are important cosmic laboratories that enable some of the most precise tests of Einstein's general theory of relativity. They also play an important role as potential gravitational-wave sources for the LIGO detectors.

Neutron stars are the highly magnetized and extremely dense remnants of supernova explosions. Like a rapidly rotating cosmic lighthouse they emit beams of radio waves into space. If Earth happens to lie along one of the beams, large radio telescopes can detect the neutron star as a pulsating celestial source: a radio pulsar.

A Rare Pulsar Breed

Most of the about 2,500 known radio pulsars are isolated, i.e. spinning alone in space. Only 255 are in binary systems with a companion star, and only every 20th of those is in orbits with another neutron star.

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"These rare double neutron star systems are unique laboratories for fundamental physics, enabling measurements that are impossible to obtain in any laboratory on Earth," says Bruce Allen, director at the Max Planck Institute for Gravitational Physics in Hannover, director of Einstein@Home and co-author of the study published in The Astrophysical Journal. "That is why we need large telescopes like the Arecibo observatory and sensitive data analysis 'machines' like Einstein@Home to discover as many of these exciting objects as possible."

The PALFA Pulsar Survey and Einstein@Home Discover PSR J1913+1102

The new discovery was made in data from the Arecibo radio telescope. The PALFA consortium (PALFA: "Pulsar Surveys with the Arecibo L-Feed Array"), an international team of scientists, conducts a survey of the sky with the observatory to find new radio pulsars. The PALFA survey so far has discovered 171 radio pulsars. The data are also analyzed by the Einstein@Home distributed computing project, which has made 31 of these discoveries.

Einstein@Home aggregates the computing power provided by more than 40,000 volunteers from all around the world on their 50,000 laptops, PCs, and smartphones. The project is one of the largest distributed volunteer computing projects, and its computing power of 1.7 petaflops puts it among the 60 largest supercomputers in the world.

After the initial discovery of the binary system by Einstein@Home in February 2012, the PALFA researchers observed the system repeatedly with the Arecibo telescope to precisely measure the orbit of the radio pulsar, which spins once every 27.2 milliseconds (37 times each second). Their observations showed that the object called PSR J1913+1102 (this name encodes a sky position, the pulsar's celestial "address") consists of two stars orbiting one another in a little less than five hours in a slightly elliptical orbit.

From measuring how the pulsar rotates slightly slower over time, the scientists could also infer its magnetic field to be a few billion times that of our Earth. This is relatively weak for a neutron star and indicates an episode of matter accretion from the companion star in the distant past. This accretion episode, however, would have circularized the orbit, too. The observed ellipticity of the orbit is testament of the companion exploding in a supernova and leaving behind a second neutron star. The kick of the supernova explosion did not disrupt the binary system but made its orbits elliptical.

Record-Breaking System Shows Einstein's Relativity in Action

Moreover, the research team measured an effect of Einstein's general theory of relativity in the binary system. Like the orbit of Mercury around our Sun, the elliptical orbit of the radio pulsar rotates over time. But while Mercury's orbit rotates by only 0.0001 degree per year, J1913+1102's orbit rotates 47,000 times faster: a full 5.6 degrees each year. The magnitude of this effect, known as relativistic periastron advance, depends on the combined mass of the radio pulsar and its companion, thereby allowing a measurement of this quantity.

"With a total mass of 2.88 times that of our Sun, our discovery breaks the current record for the total mass of the known double neutron star systems," says Dr. Paulo Freire, researcher at the Max Planck Institute for Radio Astronomy in Bonn. "We expect that the pulsar is heavier than the companion star, but with our current observations we cannot yet determine the individual masses of the pulsar and its neutron star companion. However, continued observations will enable this measurement."

If the pulsar indeed turns out to be substantially more massive than the companion, this system will be significantly different from all the other known double neutron star systems. In that case, it promises to become one of the best known laboratories for testing theories of gravitation alternative to Einstein's theory of general relativity.

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Since the companion star also is a neutron star, it might also be detectable as a radio pulsar -- provided its radio beam also sweeps over the Earth. But that does not seem to be the case for J1913+1102. The researchers painstakingly searched all their data for radio pulsations from the companion -- but in vain. They did not find any sign of radio emission from the companion.

Potential LIGO Sources

As the neutron stars orbit one another, their orbits shrink because the system emits gravitational waves. Measurements of this effect might allow to determine the individual masses of both the pulsar and its companion. Researchers hope to learn more about the little-known stellar evolution of such binary systems and the unknown properties of matter at the density of an atomic nucleus.

Discoveries like this one are also interesting for the era of gravitational-wave astronomy that began in September 2015 with the first direct detection of gravitational waves. "Finding double neutron stars systems similar to J1913+1102 is useful for the gravitational-wave science community. It helps us better understand how often these systems merge, and how often Advanced LIGO might detect the signals of merging neutron stars in the future," concludes Prof. Michael Kramer, director at the Max Planck Institute for Radio Astronomy

Source: Spaceref.com Return to Contents

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Space Image of the Week

NGC 4696: Filaments around a Black Hole

Explanation: What's happening at the center of elliptical galaxy NGC 4696? There, long tendrils of gas and dust have been imaged in great detail as shown by this recently released image from the Hubble Space Telescope. These filaments appear to connect to the central region of the galaxy, a region thought occupied by a supermassive black hole. Speculation holds that this black hole pumps out energy that heats surrounding gas, pushes out cooler filaments of gas and dust, and shuts down star formation. Balanced by magnetic fields, these filaments then appear to spiral back in toward and eventually circle the central black hole. NGC 4696 is the largest galaxy in the Centaurus Cluster of Galaxies, located about 150 million light years from Earth. The featured image shows a region about 45,000 light years across.

Image Credit: NASA, ESA, Hubble, A. Fabian

Source: Astronomy Picture of the Day Return to Contents