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Space News Update — August 8, 2017 —

Contents

In the News

Story 1:

Twilight Observations Reveal Huge Storm on Neptune

Story 2:

Astronomers Identify Oldest Known Asteroid Family

Story 3:

A Tale of Three Stellar Cities

Departments

The Night Sky

ISS Sighting Opportunities

NASA-TV Highlights

Space Calendar

Food for Thought

Space Image of the Week

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1. Twilight Observations Reveal Huge Storm on Neptune

While observing Neptune at dawn with the Keck Telescope, grad student Ned Molter discovered an unusually bright,

nearly circular storm system near Neptune’s equator, a region where astronomers have never seen a bright cloud. The

center of the storm complex is ~9,000 km across, about 3/4 the size of Earth, or 1/3 of Neptune’s radius. (N. Molter/I. De

Pater, UC Berkeley/C. Alvarez, W. M. Keck Observatory)

Spectacular sunsets and sunrises are enough to dazzle most of us, but to astronomers, dusk and dawn are a

waste of good observing time. They want a truly dark sky.

Not Ned Molter, a UC Berkeley astronomy graduate student. He set out to show that some bright objects can

be studied just as well during twilight, when other astronomers are twiddling their thumbs, and quickly

discovered a new feature on Neptune: A storm system nearly the size of Earth.

“Seeing a storm this bright at such a low latitude is extremely surprising,” said Molter, who spotted the storm

complex near Neptune’s equator during a dawn test run of twilight observing at W. M. Keck Observatory on

Maunakea, Hawaii. “Normally, this area is really quiet and we only see bright clouds in the mid-latitude bands,

so to have such an enormous cloud sitting right at the equator is spectacular.”

This massive storm system, which was found in a region where no bright cloud has ever been seen before, is

about 9,000 kilometers in length, or one-third the size of Neptune’s radius, spanning at least 30 degrees in

both latitude and longitude. Molter observed it getting much brighter between June 26 and July 2.

“Historically, very bright clouds have occasionally been seen on Neptune, but usually at latitudes closer to the

poles, around 15 to 60 degrees north or south,” said Imke de Pater, a UC Berkeley professor of astronomy and

Molter’s adviser. “Never before has a cloud been seen at or so close to the equator, nor has one ever been this

bright.”

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The discovery of Neptune’s mysterious equatorial cloud complex was made possible by the new Keck Visiting

Scholars Program, launched this summer, which gives graduate students and post-doctoral researchers

experience working at the telescope, while contributing to Keck Observatory and its scientific community.

“This result by Imke and her first-year graduate student, Ned, is a perfect example of what we’re trying to

accomplish with the Keck Visiting Scholars Program,” said Anne Kinney, chief scientist at Keck Observatory.

“Ned is our first visiting scholar, and his incredible work is a testament to the value of this program. It’s just

been an outrageous success.”

Molter is one of eight scholars accepted into the program this year. His assignment during his six-week stay at

the Observatory was to develop a more efficient method for twilight observing, making use of time that

otherwise might not be used. Most observers in the Keck Observatory community peer deep into the night sky

and cannot observe their targets during twilight.

“Ned had never observed before, and he’s very bright, so when Anne told me about the program, I knew he

would be the perfect student for it,” said de Pater. “Now that we’ve discovered this interesting cloud complex

in Neptune, Ned has a running start on a nice paper for his Ph.D. thesis.”

Images of Neptune taken during twilight observing revealed an extremely large bright storm system near

Neptune’s equator (labeled ‘cloud complex’ in the upper figure), a region where astronomers have never seen

a bright cloud. The center of the storm complex is ~9,000 km across, about 3/4 the size of Earth, or 1/3 of

Neptune’s radius. The storm brightened considerably between June 26 and July 2, as noted in the logarithmic

scale of the images taken on July 2. (N. Molter/I. De Pater, UC Berkeley/C. Alvarez, W. M. Keck Observatory)

Source: University of California, Berkeley Return to Contents

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2. Astronomers Identify Oldest Known Asteroid Family

SwRI Part of International Team Identifying Primordial Asteroids

An artist's impression of an asteroid breaking up. Credit: NASA/JPL-Caltech

Boulder Colorado’s Southwest Research Institute (SwRI) was part of an international team that

recently discovered a relatively unpopulated region of the main asteroid belt, where the few asteroids present

are likely pristine relics from early in solar system history. The team used a new search technique that also

identified the oldest known asteroid family, which extends throughout the inner region of the main asteroid

belt.

The main belt contains vast numbers of irregularly shaped asteroids, also known as planetesimals, orbiting the

Sun between Mars and Jupiter. As improved telescope technology finds smaller and more distant asteroids,

astronomers have identified clusters of similar-looking bodies clumped in analogous orbits. These familial

objects are likely fragments of catastrophic collisions between larger asteroids eons ago. Finding and studying

asteroid families allows scientists to better understand the history of main belt asteroids.

“By identifying all the families in the main belt, we can figure out which asteroids have been formed by

collisions and which might be some of the original members of the asteroid belt,” said SwRI Astronomer Dr.

Kevin Walsh, a coauthor of the online Science paper detailing the findings. “We identified all known families

and their members and discovered a gigantic void in the main belt, populated by only a handful of asteroids.

These relics must be part of the original asteroid belt. That is the real prize, to know what the main belt looked

like just after it formed.”

Identifying the very oldest asteroid families, those billions of years old, is challenging, because over time, a

family spreads out. As asteroids rotate in orbit around the Sun, their surfaces heat up during the day and cool

down at night. This creates radiation that can act as a sort of mini-thruster, causing asteroids to drift widely

over time. After billions of years, family members would be almost impossible to identify, until now. The team

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used a novel technique, searching asteroid data from the inner region of the belt for old, dispersed families.

They looked for the “edges” of families, those fragments that have drifted the furthest.

“Each family member drifts away from the center of the family in a way that depends on its size, with small

guys drifting faster and further than the larger guys,” said team leader Marco Delbo, an astronomer from the

Observatory of Cote d’Azur in Nice, France. “If you look for correlations of size and distance, you can see the

shapes of old families.”

“The family we identified has no name, because it is not clear which asteroid is the parent,” Walsh said. “This

family is so old that it appears to have formed over 4 billion years ago, before the gas giants in the outer solar

system moved into their current orbits. The giant planet migration shook up the asteroid belt, removing many

bodies, possibly including the parent of this family.”

The team plans to apply this new technique to the entire asteroid belt to reveal more about the history of the

solar system by identifying the primordial asteroids versus fragments of collisions. This research was

supported by the French National Program of Planetology and the National Science Foundation. The resulting

paper, “Identification of a primordial asteroid family constrains the original planetesimal population,” appears

in the August 3, 2017, online edition of Science.

Astronomers have identified the oldest asteroid families and, by process of elimination, the oldest intact asteroids in the

main belt. A team including SwRI scientists developed a technique to identify ancient asteroid families that have drifted

apart. Asteroid surfaces heat up during the day (as illustrated by this image) and cool down at night, giving off radiation

that can act as a sort of mini-thruster. This force can cause asteroids to drift widely over time, making it difficult to

identify families of fragments leftover after asteroid collisions eons ago.

Source: Southwest Research Institute and Phys.org Return to Contents

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3. A Tale of Three Stellar Cities

The wide-field optical camera on ESO’s VLT Survey Telescope (VST) — has captured the spectacular Orion Nebula and its

associated cluster of young stars in great detail, producing this beautiful new image. This famous object, the birthplace of

many massive stars, is one of the closest stellar nurseries, at a distance of about 1350 light-years [1]. On this plot

different populations of young stars are marked in different colors. The blue ones are oldest and the red youngest, with

green ones an intermediate age. These stars seems to have formed in three bursts of star formation during the last three

million years. Credit: ESO/G. Beccari

This is more than just a pretty picture. A team led by ESO astronomer Giacomo Beccari has used these data of

unparallelled quality to precisely measure the brightness and colours of all the stars in the Orion Nebula

Cluster. These measurements allowed the astronomers to determine the mass and ages of the stars. To their

surprise, the data revealed three different sequences of potentially different ages.

“Looking at the data for the first time was one of those ‘Wow!’ moments that happen only once or twice in an

astronomer's lifetime,” says Beccari, lead author of the paper presenting the results. “The incredible quality of

the OmegaCAM images revealed without any doubt that we were seeing three distinct populations of stars in

the central parts of Orion.”

Monika Petr-Gotzens, co-author and also based at ESO Garching, continues, “This is an important result. What

we are witnessing is that the stars of a cluster at the beginning of their lives didn’t form altogether

simultaneously. This may mean that our understanding of how stars form in clusters needs to be modified.”

The astronomers looked carefully at the possibility that instead of indicating different ages, the different

brightnesses and colours of some of the stars were due to hidden companion stars, which would make the

stars appear brighter and redder than they really were. But this idea would imply quite unusual properties of

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the pairs, which have never before been observed. Other measurements of the stars, such as their rotation

speeds and spectra, also indicated that they must have different ages [2].

“Although we cannot yet formally disprove the possibility that these stars are binaries, it seems much more

natural to accept that what we see are three generations of stars that formed in succession, within less than

three million years,” concludes Beccari.

The new results strongly suggest that star formation in the Orion Nebula Cluster is proceeding in bursts, and

more quickly than had been previously thought.

Notes

[1] The Orion Nebula has been studied by many of ESO’s telescopes, including images in visible light from the

MPG/ESO 2.2-metre telescope (eso1103) and infrared images from VISTA (eso1701) and the HAWK-

I instrument on the Very Large Telescope (eso1625).

[2] The group also found that each of the three different generations rotate at different speeds — the

youngest stars rotate the fastest, and the oldest stars rotate the slowest. In this scenario, the stars would

have formed in quick succession, within a time frame of three million years.

Source: European Southern Observatory Return to Contents

This chart shows the location of the Orion Nebula (Messier 42) in the sword of the

famous constellation of Orion (the Hunter). This map shows most of the stars visible to the unaided eye under good conditions and the Orion Nebula itself is highlighted with a

red circle on the image. This grand star formation region can be seen with the

unaided eye and is an impressive sight in moderate-sized amateur telescopes.

Credit: ESO, IAU and Sky & Telescope

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The Night Sky

The radiant of the Perseid meteor shower is low in the northeastern sky by 11 p.m. for observers at mid-northern

latitudes. Sky & Telescope diagram

Source: Sky and Telescope Return to Contents

Tuesday, August 8

The Big Dipper hangs diagonally in the northwest after dusk. From its midpoint, look to the right to find

Polaris (not very bright) glimmering due north as always.

Polaris is the handle-end of the Little Dipper. The only other parts of the Little Dipper that are even modestly

bright — especially through the moonlight! — are the two stars forming the outer end of its bowl. On August

evenings you'll find them to Polaris's upper left, by about a fist and a half at arm's length. They're called the

Guardians of the Pole, since they circle around Polaris throughout the night and throughout the year.

Wednesday, August 9

The waning gibbous Moon rises in the east at about the end of twilight. Look to its upper left for the Great

Square of Pegasus, balancing on one corner.

Thursday, August 10

The W of Cassiopeia, tilted only a little, is nicely up in the northeast these evenings. Its right-hand side is the

brightest. Watch it rise higher and tilt further through the night and through the next few months.

Friday, August 11

The Perseid meteor shower should be at its maximum late tonight and late tomorrow night. The nearly

last-quarter Moon will light the sky late at night. But the brightest meteors will still shine through the

moonlight, and there's a prediction out that this year's underlying shower may be somewhat richer than usual.

You may see one every couple minutes on average, depending on the brightness of your sky.

Waxing toward full, the Moon passes over Antares and Saturn later in the week.

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ISS Sighting Opportunities (from Denver)

Date Visible Max Height Appears Disappears

Tue Aug 8, 8:27 PM 4 min 17° 12° above NNW 10° above ENE

Tue Aug 8, 10:04 PM 1 min 60° 29° above NW 60° above WNW

Wed Aug 9, 9:12 PM 3 min 50° 27° above NNW 24° above E

Wed Aug 9, 10:47 PM < 1 min 11° 11° above W 11° above W

Thu Aug 10, 9:55 PM 2 min 30° 16° above W 30° above SW

Fri Aug 11, 9:04 PM 3 min 63° 34° above WNW 22° above SE

Sighting information for other cities can be found at NASA’s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Time Zone)

Wednesday, August 9

10 a.m. - ISS Expedition 52 In-Flight Media Event with KMA Radio, Shenandoah, IA and Space.com and

NASA Flight Engineer Peggy Whitson (starts at 10:05 a.m.) (all channels)

Thursday, August 10

12:30 p.m. - ISS Expedition 52 In-Flight Event for a NASA JSC Podcast with NASA Flight Engineer Jack

Fischer (all channels)

Friday, August 11

10 a.m. - ISS Expedition 52 In-Flight Interview for a JSC Facebook Live and NASA Flight Engineer

Randy Bresnik (all channels)

Watch NASA TV online by going to the NASA website. Return to Contents

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Space Calendar

Aug 08 - Apollo Asteroid 2003 OT13 Near-Earth Flyby (0.093 AU)

Aug 08 - Aten Asteroid 153415 (2001 QP153) Near-Earth Flyby (0.095 AU)

Aug 08 - Asteroid 25924 Douglasadams Closest Approach To Earth (1.162 AU)

Aug 08 - Asteroid 3673 Levy Closest Approach To Earth (1.405 AU)

Aug 08 - Asteroid 12477 Haiku Closest Approach To Earth (1.412 AU)

Aug 08-10 - Conference: From Chandra to Lynx - Taking the Sharpest X-ray Vision Fainter and Farther, Cambridge, Massachussetts

Aug 08-10 - Conference: The Early History of Planetary Systems and Habitable Planets, Tartu, Estonia

Aug 08-10 - Meeting: Review of Planetary Protection Policy Development Processes, Woods Hole, Massachusetts

Aug 08-11 - Workshop: Unlocking the Climate Record Stored within Mars' Polar Layered Deposits, Pasadena, California

Aug 09 - Moon Occults Neptune

Aug 09 - Comet 198P/ODAS Closest Approach To Earth (2.783 AU)

Aug 09 - Asteroid 6227 Alanrubin Closest Approach To Earth (1.809 AU)

Aug 09 - International Space Station Stakeholder Workshop, Washington DC

Aug 09 - Colloquium: KM3NeT - The Next Generation Neutrino Telescope, Sydney, Australia

Aug 09-11 - 8th Planetary Crater Consortium Meeting, Flagstaff, Arizona

Aug 09-13 - 75th World Science Fiction Convention (WORLDCON 75), Helsinki, Finland

Aug 10 - Comet 73P-AL/Schwassmann-Wachmann Closest Approach To Earth (0.277 AU)

Aug 10 - Comet 38P/Stephan-Oterma At Opposition (3.978 AU)

Aug 10 - Amor Asteroid 2017 OF7 Near-Earth Flyby (0.049 AU)

Aug 10 - Apollo Asteroid 2015 XO128 Near-Earth Flyby (0.095 AU)

Aug 10 - Asteroid 945 Barcelona Closest Approach To Earth (2.029 AU)

Aug 10 - Asteroid 17062 Bardot Closest Approach To Earth (2.055 AU)

Aug 10 - Lecture: Black Holes' Last Tango in Space - LIGO and the Dawn of Gravitational-wave Astronomy, Kamuela, Hawaii

Aug 10-11 - Regional Workshop on Himalayan GEOSS, Kathmandu, Nepal

Aug 11 - Michibiki 3 (QZS-3) H-2A Launch

Aug 11 - Cassini, Distant Flyby of Titan

Aug 11 - Comet 73P-AP/Schwassmann-Wachmann Perihelion (0.959 AU)

Aug 11 - Comet 29P/Schwassmann-Wachmann At Opposition (4.813 AU)

Aug 11 - Asteroid 1587 Kahrstedt Occults HIP 32311 (5.4 Magnitude Star)

Aug 11 - Asteroid 8991 Solidarity Closest Approach To Earth (1.661 AU)

Aug 11 - Asteroid 18024 Dobson Closest Approach To Earth (2.184 AU)

Aug 11 - Stargazing Lecture: The Origin of the Universe and the Arrow of Time, Pasadena, California

Aug 11-13 - Mt. Carleton Star Party, Mount Carleton Provincial Park, Canada

Source: JPL Space Calendar Return to Contents

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Food for Thought

UCI Celestial Census Indicates That Black Holes Pervade the Universe

A representative graphic shows two black holes merging. Credit: NASA

After conducting a cosmic inventory of sorts to calculate and categorize stellar-remnant black holes,

astronomers from the University of California, Irvine have concluded that there are probably tens of millions of

the enigmatic, dark objects in the Milky Way – far more than expected.

“We think we’ve shown that there are as many as 100 million black holes in our galaxy,” said UCI chair and

professor of physics & astronomy James Bullock, co-author of a research paper on the subject in the current

issue of Monthly Notices of the Royal Astronomical Society.

UCI’s celestial census began more than a year and a half ago, shortly after the news that the Laser

Interferometer Gravitational-Wave Observatory, or LIGO, had detected ripples in the space-time continuum

created by the distant collision of two black holes, each the size of 30 suns.

“Fundamentally, the detection of gravitational waves was a huge deal, as it was a confirmation of a key

prediction of Einstein’s general theory of relativity,” Bullock said. “But then we looked closer at the

astrophysics of the actual result, a merger of two 30-solar-mass black holes. That was simply astounding and

had us asking, ‘How common are black holes of this size, and how often do they merge?’”

He said that scientists assume most stellar-remnant black holes – which result from the collapse of massive

stars at the end of their lives – will be about the same mass as our sun. To see evidence of two black holes of

such epic proportions finally coming together in a cataclysmic collision had some astronomers scratching their

heads.

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UCI’s work was a theoretical investigation into the “weirdness of the LIGO discovery,” Bullock said. The

research, led by doctoral candidate Oliver Elbert, was an attempt to interpret the gravitational wave detections

through the lens of what is known about galaxy formation and to form a framework for understanding future

occurrences.

“Based on what we know about star formation in galaxies of different types, we can infer when and how many

black holes formed in each galaxy,” Elbert said. “Big galaxies are home to older stars, and they host older

black holes too.”

According to co-author Manoj Kaplinghat, UCI professor of physics & astronomy, the number of black holes of

a given mass per galaxy will depend on the size of the galaxy.

The reason is that larger galaxies have many metal-rich stars, and smaller dwarf galaxies are dominated by big

stars of low metallicity. Stars that contain a lot of heavier elements, like our sun, shed a lot of that mass over

their lives. When it comes time for one to end it all in a supernova, there isn’t as much matter left to collapse

in on itself, resulting in a lower-mass black hole. Big stars with low metal content don’t shed as much of their

mass over time, so when one of them dies, almost all of its mass will wind up in the black hole.

“We have a pretty good understanding of the overall population of stars in the universe and their mass

distribution as they’re born, so we can tell how many black holes should have formed with 100 solar masses

versus 10 solar masses,” Bullock said. “We were able to work out how many big black holes should exist, and

it ended up being in the millions – many more than I anticipated.”

In addition, to shed light on subsequent phenomena, the UCI researchers sought to determine how often

black holes occur in pairs, how often they merge, and how long it takes. They wondered whether the 30-solar-

mass black holes detected by LIGO were born billions of years ago and took a long time to merge or came into

being more recently (within the past 100 million years) and merged soon after.

“We show that only 0.1 to 1 percent of the black holes formed have to merge to explain what LIGO saw,”

Kaplinghat said. “Of course, the black holes have to get close enough to merge in a reasonable time, which is

an open problem.”

Elbert said he anticipates many more gravitation wave detections so that he and other astronomers can

determine if black holes collide mostly in giant galaxies. That, he said, would tell them something important

about the physics that drive them to coalesce.

According to Kaplinghat, they may not have to wait too long, relatively speaking. “If the current ideas about

stellar evolution are right, then our calculations indicate that mergers of even 50-solar-mass black holes will be

detected in a few years,” he said.

Source: University of California Irvine Return to Contents

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Space Image of the Week

The Dust Monster in IC 1396 Image Credit & Copyright: Anis Abdul

Explanation: Is there a monster in IC 1396? Known to some as the Elephant's Trunk Nebula, parts of gas

and dust clouds of this star formation region may appear to take on foreboding forms, some nearly human.

The only real monster here, however, is a bright young star too far from Earth to hurt us. Energetic light from

this star is eating away the dust of the dark cometary globule near the top of the featured image. Jets and

winds of particles emitted from this star are also pushing away ambient gas and dust. Nearly 3,000 light-years

distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an

apparent width of more than 10 full moons.

Source: NASA APOD Return to Contents