Fast-spinning asteroid tears itself to pieces

Top panel shows a wide-angle view of the main nucleus and smaller fragments embedded in a long dust trail.

Top panel shows a wide-angle view of the main nucleus of the crumbling asteroid P/2012 F5 and smaller fragments embedded in a long dust trail. Bottom panel shows a close-up view with the trail removed for a clearer view of the individual fragments. Credit: M. Drahus, W. Waniak (OAUJ) / W. M. Keck Observatory

A team of astronomers led by team led by Michal Drahus of the Jagiellonian University (Krakow, Poland) used one of the twin 10-meter (394-inch) telescopes of the W.M. Keck Observatory in Hawaii to study the strange behavior of four comet-like asteroids.

Most of the hundreds of thousands of known asteroids are made of rock and don’t develop fuzzy comas and tails the way similar-sized icy comets do. But since 2010, astronomers have uncovered a small number of oddball, “active asteroids” that mimic comets by releasing clouds of dust as they spin.

Artist illustration of the active asteroid P/2012 F5 trailing a tail of dust spun off due to its fast rotation. Credit: SINC

Artist illustration of the active asteroid P/2012 F5 trailing a tail of dust spun off due to its fast rotation. Credit: SINC

One of them, P/2012 F5 (Gibbs), located in the outer zone of the main asteroid belt, spins so fast, it’s literally falling apart. Using the Keck II telescope, Drahus and team discovered at least four fragments flung from the object.

We knew the asteroid was an active one because it had previously released a cloud of dust in a single, quick impulse back around July 1, 2011. Like a comet, the object looked slightly fuzzy and left a left a dust trail; this time around, P/2012 F5 took it to the next level and deposited a string of tiny asteroid satellites.

There are two theories on how otherwise quiet asteroids can suddenly explode to life — through a collision with another smaller asteroid or by “rotational disruption”, which is exactly what it sounds like.

Yorping the day away. Illustration showing how sunlight absorbed unevenly by an asteroid’s surface creates torque that can increase its spin rate. Illustration: Bob King

Yorping the day away. Illustration showing how sunlight absorbed unevenly by an asteroid’s surface and re-released as heat creates torque that can increase its spin rate. Illustration: Bob King

An asteroid can spin so fast that its weak gravity is overwhelmed by centrifugal force, the tendency of material to pull away from a rapidly spinning object. Centrifugal force can cause small objects like P/2012 F5 and its ilk to break apart. No surprisingly, the team measured F5’s rotation rate at just 3.24 hours, fast enough for it to theoretically explode.

So how do you spin up an asteroid until it shoots pieces of itself into space like some hell-bent disk golfer? Just add a little YORP. An acronym for Yarkovsky–O’Keefe–Radzievskii–Paddack effect, heating from the Sun can cause an asteroid’s tilt and rotation rate to change over time.

Sunlight shining on an asteroid warms the rock which releases the energy as heat, giving the object a tiny push. Assuming the asteroid is irregular in shape – and most are because they’re so small – some areas get hotter and give off more heat than others. The imbalance causes a torque on the asteroid, increasing its spin rate. Depending on the shape of the asteroid and variations in the reflectivity of its surface (some areas may be darker or lighter than others), those smidgeons of thrust can add up to twirl an asteroid to the breaking point.

And because many asteroids are little more than rubble piles, breaking up is easy to do.

This illustration shows one possible explanation for the disintegration of asteroid P/2013 R3. Sunlight absorbed unequally across the asteroid’s surface can spin up its rotation and cause it to fall apart. More details on how this happens below. Credit: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI)

Sunlight absorbed unequally across the asteroid’s surface can spin up its rotation rate and cause it to fall apart. While it’s possible P/2012 F5 was struck by another object, this explanation best fits the observations. Credit: NASA, ESA, D. Jewitt (UCLA), and A. Feild (STScI)

“This is really cool because fast rotation has been suspected of catapulting dust and triggering fragmentation of some active asteroids and comets. But up until now we couldn’t fully test this hypothesis as we didn’t know how fast fragmented objects rotate,” Drahus said.

Astronomer Alex Gibbs discovered P/2012 F5 on March 22, 2012 with the Mount Lemmon 1.5 meter reflector in Arizona. It was initially classified as a comet, based on its fuzzy look, but two independent teams quickly showed that the dust was blasted out in a single pulse about a year before the discovery – something that doesn’t happen to comets, which continuously emit dust and other materials as the Sun vaporizes ice from their nuclei.

Gibb’s find and the other known active asteroids are all under 0.6 miles or one kilometer across. So tiny they’re incredibly faint. That’s why the biggest telescope on Earth was needed to dig down into the details and uncover the tale of an asteroids torn asunder by nothing more than sunlight.

Ceres has chicken pox / Fresh Pluto pix

Animation made from still images of Ceres taken by Dawn on Feb. 4, 2015. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

New images from NASA’s Dawn spacecraft reveal lots more about this mysterious little world from the asteroid belt. These latest were taken on Feb. 4 from a distance of about 90,000 miles (145,000 km) and show a host of new features including craters with central peaks – just like the lunar version – a clearer view of the curious white spot and a host of other small, white dots.

Processed animation of the still images of Ceres. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

It’s tempting to guess what we’re looking at. Are the white spots relatively fresh impact craters, hills or just variations in how the asteroid’s surface reflects light.

As for the big “mystery white spot”, it appears to to my eye like a depression when it first rotates around Ceres’ limb. Later, as the feature departs, it looks more like a hill or mountain sticking up from the surface. You can really see it poking up in the processed animation at right.

Still shot of Ceres with the big white spot clearly looking like a mountain peak. Credit:  NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

We won’t have to wait for long to get a clear answer. Dawn will slip into orbit around Ceres on March 6.

This animation of Pluto and its moon Charon, taken by NASA’s New Horizons spacecraft, was magnified four times to make the objects more visible. Credit: NASA/JHU APL/SwRI

Meanwhile, NASA’s New Horizons spacecraft returned its first new images of Pluto earlier this week, as the probe closes in on the dwarf planet. Although it’s still just a pixelated dot, Pluto and its largest moon Charon span more pixels and look brighter than previous photos from last July.

The images come on the 109th birthday of Clyde Tombaugh, who discovered the distant icy world at Lowell Observatory in Flagstaff, Ariz. in 1930.

“Pluto is finally becoming more than just a pinpoint of light,” said Hal Weaver, New Horizons project scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Speeding along at 31,000 mph, New Horizons is rapidly approaching the dwarf planet. It’s traveled over 3 billion miles since its launch in January 2006 and is expected to make a close flyby of Pluto and its moons on July 14. When these photos were taken the spacecraft was still 126 million miles (203 million km) or 1.3 Earth-Sun distances from the dwarf planet.

Between the European Space Agency’s Rosetta mission at Comet 67P, the arrival of Dawn at Ceres in March and the Pluto flyby, 2015 looks to be a good year for getting closely acquainted with the solar system’s “minor” characters

Best-ever pix of Ceres / Speedy asteroid courts tiny moon

This image, taken 147,000 miles (237,000 km) from Ceres on January 25, 2015 by NASA’s Dawn spacecraft, is part of a series of views representing the best look so far at the dwarf planet. It’s even better pictures of Ceres taken by the Hubble Space Telescope in 2003 and 2004. Credit: NASA/JPL-Caltech

Sit back and take in the view. You can see a new world coming into focus right before your eyes. The bright white spot, the origin of which is still unknown, stands out clearly, while dozens of craters lie at the limit of resolution. The new photos are 30 percent clearer than those taken with the Hubble in 2003 and 2004. Nothing like driving to the seen instead of staring at it from afar with a long lens.

This animation of the dwarf planet Ceres was made by combining images taken by NASA’s Dawn spacecraft on January 25, 2015. Credit: NASA/JPL-Caltech

We looked at Ceres only a week ago when Dawn was 91,000 miles farther out. While I’m not quite ready to sing the lyrics to the Jimmy Cliff song “I Can See Clearly Now”, it’s certainly a better picture.

This animation, created from 20 individual radar images, clearly show the rough outline of 2004 BL86 and its newly-discovered moon. Click for larger animation. Credit: NASA/JPL-Caltech

Speaking of things that spin, check out the radar movie made from images taken during yesterday’s flyby of asteroid 2004 BL86 by NASA’s Goldstone Radar facility in California. Wow, it has a moon! 2004 BL86 measures about 1,100 feet (325 meters) across while its moon is approximately 230 feet (70 meters) across.

Asteroid 2004 BL86 buzzes Earth as it crosses through Cancer last night. Time lapse by John Chumack

One interesting oddity. The moon appears to be revolving in an orbit perpendicular to that of the main body. Many moons orbit in or near the plane of the equator. Perhaps it’s an artifact of processing images created by radar pings. For more on the discovery, click HERE.

All eyes will be on asteroid 2004 BL86 Monday night

Big boy asteroid 2004 BL86 will pass close enough to Earth tomorrow night (Jan. 26th) to show up in small telescopes. Credit: NASA

January’s been a busy month for skywatchers. Between bright comets, their outbursts and the recent triple shadow transit at Jupiter it’s finally time to catch our collective breath. Maybe hole up in the house and keep warm.

Banish the thought.

Monday night Jan. 26th an obscure asteroid with the moniker 2004 BL86 will make a relatively close pass of Earth, zipping by at 3.1 times the distance of the moon or some 750,000 miles (1.2 million km).

Not a big deal, right? At least once a month a space rock gets this close or closer. Except that this space rock isn’t your typical “tiny house”. 2004 BL86 is 2,230 feet (680 meters) across – more like a space mountain – and big enough and close enough to be easily visible in a small telescope. Even even a Wal-Mart scope will show it. No exaggeration.

This graphic shows the path of asteroid 2004 BL86 with its position shown for Jan. 19th. Closest approach to Earth occurs around 10 a.m (CST) Jan. 26th. The asteroid will fade after Monday but continue to be visible in modest amateur telescopes through about Jan. 29th. Click to see an animation. Credit: NASA/JPL-Caltech

At magnitude +9 under a dark sky the asteroid would be faintly visible with a pair of 10×50 binoculars, but the half moon will be out, so you’ll need a 3-inch or larger scope binoculars in the 15×70 range to spot it. The good news is that the object remains close to 9th magnitude from 6 p.m. to midnight (CST) with peak brightness around 10 p.m.

Discovered 11 years ago, hence the “2004” prefix, 2004 BL86 is the largest asteroid to pass closest to Earth until 2027 when 1999 AN10 will beat it by coming within one lunar distance. This will also be the asteroid’s closest approach to our planet for at least the next two hundred years, so if you want to see it before you’re six feet under, now’s the time to put on a coat and toddle out the scope.

Map showing the hourly progress of 2004 BL86 Monday evening January 26th as crosses Cancer the Crab not far from Jupiter. Stars are shown to magnitude +9. Numbers at the tick marks show the time (CST) each hour starting at 6 p.m., then 7 p.m., 8 p.m. and so on. Click for a larger version. Created with Chris Marriott’s SkyMap program

All asteroids with well-determined orbits receive a number designation. The very first asteroid discovered, Ceres in 1801, got the #1 spot. Asteroid 13,683 Monty Python (no kidding) was discovered in August 1967. Our featured space mountain numbers 357,439 making its full designation (357439) 2004 BL86. If you’re looking for a new password, this is it.

Black stars-on-white version of the map above which you might find more useful. Click to see and download a large version.

OK, so let’s talk how to see this speeding “star”. Observers in the Americas, Europe and Africa will have the best seats when the asteroid shines brightest between 7 p.m. and midnight (CST) Monday night from a comfortably high perch in Cancer the Crab not far from the planet Jupiter.

Because 2004 BL86 will be near Earth it will be zipping along at the rate of about 2° or four moon diameters per hour. That means you’ll need to use detailed maps to find and track the asteroid as it moves in real time.

Notice that the 2004 BL86 passes near a couple relatively bright stars and even skirts the edge of the bright Beehive star cluster, also known as M44. These are good places to “lie in wait” for the object to move into the field of view. I usually pick a spot some minutes ahead of where the asteroid will be and familiarize myself with the star field. That way, when it arrives, it really stands out. Remember, you’ll be looking for a star-like object slowly crossing the field of view. In reality, it’s sailing by Earth at around 35,000 mph.

Detailed map showing stars down to magnitude +9.5. Click to see and print out a larger version. Created with Chris Marriott’s SkyMap software

Another thing to remember is that near-Earth asteroids will sometimes be a little bit off a particular track depending on your location. Not much but enough that I recommend you scan not just the single spot where you expect to see it but also nearby in the field of view. Just look for a “star” not plotted on the map and keep an eye on it for movement.

Once you nab your prey, follow it for 10, 15 or 30 minutes. It makes for good sport to watch it brush by stars along its path. The closer it comes to a star the more dramatic its apparent motion appears. You should also watch for changes in its brightness as the asteroid rotates. Depending upon shape and rotation rate (unknown at this point) asteroids can show large enough brightness variations to be seen visually at the telescope.

Radar images like these made of asteroid 2007 PA8 will also be made during 2004 BL86’s flyby. Click to enlarge. Credit: NASA/JPL-Caltech

You won’t be the only one watching. Astronomers plan to use NASA’s Deep Space Network antenna at Goldstone, California and the Arecibo Observatory in Puerto Rico to ping the asteroid with microwaves to generate images of it during the time around its closest approach. We hope to share those pictures as soon as they’re available.

As always, Dr. Gianluca Masi, Italian astrophysicist, will stream live coverage of the event beginning at 1:30 p.m. (19:30 UT) Monday. And don’t worry about Earth getting hit. Not only is this asteroid many thousands of miles away, but our planet’s gravity can’t “pull” it in because the beast is moving rapidly along its own orbit. At worst, Earth’s gravity may alter its orbit some. That’s it – so enjoy!

Mystery white spot revealed in Dawn’s new photos of Ceres

The Dawn spacecraft observed Ceres for an hour on Jan. 13, 2015, from a distance of 238,000 miles (383,000 km). A little more than half of its surface was observed at a resolution of 27 pixels. This animation, comprised of still images, shows bright and dark features and hints of craters. Ceres rotates once every 9 hours. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI

Only 27 pixels across and yet this new image of Ceres by the Dawn spacecraft is nearly as sharp as those taken by the Hubble Space Telescope. To my eye it shows even more detail, possibly because the animation accentuates the changing shades of light so clearly, revealing the asteroid in three dimensions.

Besides uneven, possibly cratered terrain, what stands out is that bright, white spot. It’s also visible in the photos taken by the Hubble Space Telescope (below). Scientists aren’t sure yet what it is, but it may be water ice lining a crater floor. Interesting, eh?

Ceres, the largest asteroid (and also a dwarf planet) resides in the main asteroid belt between Mars and Jupiter. Here it’s compared to Mars, Mercury, the moon and Vesta, Dawn’s first target. Ceres is 590 miles (950 km) across and contains 30% of the mass of the entire main belt.  Credit: NASA

“Already, the (latest) images hint at the first surface structures such as craters,” said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research in Gottingen, Germany.

Hubble photos of Ceres taken in 2003-04 are slightly sharper – for now – than those from Dawn. Credit: NASA/ESA

These latest photos are just the first in a series that are taken for navigation purposes to refine the location of the asteroid and make sure Dawn spirals in accurately on its target. On March 6th, the probe will be captured by Ceres’ gravity; once in its embrace, Dawn will study this virtually unknown world-let for 16 months.

In this image, taken January 13, 2015, the Dawn spacecraft’s visible and infrared mapping spectrometer (VIR) captures dwarf planet Ceres in both visible and infrared light. The infrared image (right) serves as a temperature map of Ceres, where white is warmer and red is colder. Credit: NASA

We won’t have to wait long for even better photos – Dawn’s images will surpass Hubble’s resolution at the next imaging opportunity, which will be at the end of this month.

Single frame of Ceres taken by Dawn shows what appear to be the outlines of craters. Credit: NASA

Ceres is thought to have a rocky core overlain by an mantle of water ice and may even harbor a subsurface ocean. It’s the largest body between the Sun and Pluto that a spacecraft has not yet visited. Because it contains ice, Ceres is believed to have formed far from the Sun. Radioactive elements in minerals that went into building the asteroid helped to heat and partially melt its interior. Insulated by an icy crust estimated at more than 60 miles (100 km) thick, liquid water may yet lurk beneath its hard rind.


Dawn begins approach to dwarf planet Ceres

Dawn approaches the dwarf planet Ceres as seen in this artist illustration. The spacecraft will arrive at the asteroid on March 6. Credit: NASA/JPL-Caltech

NASA’s Dawn spacecraft officially began its approach to the dwarf planet Ceres this week. Ceres was the first asteroid discovered and at 590 miles (950 km) across, the largest of the Main Belt asteroids that cycle between the orbits of Mars and Jupiter. No probe’s ever visited Ceres, and our best photos taken by the Hubble Space Telescope show only a mottled, blurry disk.

Dawn is currently 400,000 miles (640,000 km) from Ceres, approaching it at around 450 miles per hour (725 km/hr). It’s the only spacecraft ever to orbit two solar system targets. You probably recall its first mission (2011-2012) to the asteroid Vesta, also in the Main Belt. There we learned that Vesta mimicks a planet in miniature, having “differentiated” through radioactive heating into core, mantle and crust.

Millions of miles and more than a year separated that success from its next eagerly awaited target now just 9 weeks away.

Dual targets of Dawn – the impact-gouged asteroid Vesta (left) and still-mysterious Ceres. Credit: NASA/JPL-Caltech

“Ceres is almost a complete mystery to us,” said Christopher Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles. “Ceres, unlike Vesta, has no meteorites linked to it to help reveal its secrets. All we can predict with confidence is that we will be surprised.”

Yes, meteorites. We have tons of samples of Vesta in pieces fallen to Earth as eucrite, Howardite and diogenite meteorites, a subset of a larger clan of meteorites called achondrites. Achondrites (Ay-KON-drites) are rocks that have been melted and processed on asteroids and resemble volcanic rocks on Earth.

The two planetary bodies are thought to have gone down different evolutionary roads. Ceres likely formed later than Vesta and possesses a cooler interior. The fact that Vesta appears to have very little water tells us it formed earlier, when radioactive material was more abundant. Heat from radioactivity would have cooked out the water. Ceres, in contrast, has a thick ice mantle and may even have an ocean beneath its icy crust.

Great explainer on Dawn’s ion propulsion engine

NASA employed ion propulsion to travel the many millions of miles of the dual mission cheaply and efficiently. Instead of conventional rocket fuel, an electric charge is applied to atoms of xenon, a gas used in photographic flashes (strobes). Next, an electrically-charged plate at the back of the engine accelerates the electrified atoms out of the thruster. As they leave, they push back against the engine, nudging the spacecraft forward.

Ion engines thrust with a light touch that begins slowly but adds up soon enough in the frictionless environment of space. Check the video for more details.

Later next month, we’ll start to receive better images of Ceres than Hubble’s been able to provide. We’ll update the mission’s progress at that time.

Did Jupiter deport 8 billion asteroids to the Oort Cloud?

1996 PW has a highly elongated orbit  just like a comet from the Oort Cloud – except it’s an asteroid. Astronomers now think they know how it got there. 1996 PW is about 5-10 miles (8-16 km) across. Credit: NASA/JPL-Horizons

Our view of the solar system will forever be incomplete. While frustrating at first blush, it means that fresh discoveries are always just around the corner. Case in point. On August 9, 1996 astronomers atop Mt. Haleakala in Maui, Hawaii discovered a most peculiar asteroid. 1996 PW has a highly elongated that looks like a Frisbee seen from the side and takes 5,900 years to make one trip around the Sun.

When farthest, 1996 PW is 48.8 billion miles away or 104 times more distant than Pluto. That places it among the billions of icy comets that comprise the Oort Cloud, a roughly spherical cocoon centered on the Sun and extending up to a light year from it in all directions.

Like moths around the solar flame, some 500 billion comets and perhaps 8 billion asteroids occupy a vast region of space called the Oort Cloud. The Kuiper Belt is a second asteroid belt that lies beyond the orbit of Neptune.

Odd thing was, 1996 PW was an asteroid – it never exhibited a fuzzy coma or tail typical of a comet and appeared spectroscopically to be made of rock. No dust or gas of any kind was detected even when the object was closest to the Sun. So what was it doing so far from home?

Some astronomers thought it may have been an active comet long ago but depleted its ices to where it’s now unrecognizable from an asteroid. Maybe.

A new study by Andrew Shannon (University of Cambridge), based on simulations of the rolling-stone-ways of the giant planets early in the solar system’s history, points to 1996 PW once being much closer to the Sun.

The planets haven’t always been in their present day orbits. In particular, Jupiter, the largest and most gravitationally potent planet, roamed inward to the orbit of Mars before backing out to its present orbit. Gravitational interactions with the dusty disk of material around the Sun called the solar nebula pulled the planet in. Later, interaction with Saturn yanked it back out. Scientists dub the back-and-forth shimmy the “Grand Tack”.

Interaction between the dusty-gassy solar nebula surrounding the Sun the young solar system and Saturn caused Jupiter to migrate first inward and then outward, scattering the hapless asteroids as it came and went. Credit: NASA

“We refer to Jupiter’s path as the Grand Tack, because the big theme in this work is Jupiter migrating toward the sun and then stopping, turning around, and migrating back outward,” writes Kevin Walsh of the Southwest Research Institute in Boulder, Colorado in a 2011 paper in Nature. “This change in direction is like the course that a sailboat takes when it tacks around a buoy.”

Jupiter’s gravitational might profoundly affected the asteroid belt at the time. Based on Shannon’s computer simulations, the giant planet’s do-si-do created chaos, with some asteroids kicked toward the Sun, others moved to a newly-created main belt and still others booted right out of the solar system.

Many were also flung to the icy realm of the Oort just short of leaving the Sun’s domain altogether. Shannon estimates that 4% or 8 billion rocky asteroids that once orbited within 2.5 times Earth’s distance from the Sun now mingle among the cloud’s half-trillion comets. Heck, that’s more asteroids than populate the main asteroid belt!

Very few “Oort asteroids” have been discovered and you can guess why. They’re small, generally dark and incredibly far away. A comet gives itself away with a bright coma and tail. Not these guys.They’re lurkers. To find them we’ll need dedicated, large telescope surveys like the upcoming Large Synoptic Survey Telescope with its 8-meter mirror slated for “first light” in 2019. But even that great eye will be challenged – Shannon predicts only a dozen discoveries a decade with the wide-field survey telescope.

One interesting sidelight about Oort Cloud asteroids. Like comets, they do drop in on the inner solar system from time to time. 1996 PW comes within just 232 million miles (373 million km) of the Sun. If one ever did have Earth in its sights, it would be hard to spot in advance and more difficult to divert because its much faster speed. One the bright side, Shannon and team estimate an impact would occur only once every billion years. I guess I can handle those odds and drag myself to work another day.

Japan launches imaginative mission to a carbon-rich asteroid

Japan’s Hayabusa 2 asteroid mission rockets into space Tuesday. Credit: JAXA

On Tuesday at 10:22 p.m. (CST) the Hayabusa 2 mission launched from Tanegashima Space Center in southern Japan. Destination: 1999 JU3, a C-type carbon-rich asteroid nearly 3,000 feet (900 meters) across.

C-type space rocks are the most common and may have delivered some of the essential chemical building blocks important to the origin of life on Earth during the formation of the planets 4.5 billion years ago. Scientists hope to detect water and organic molecules on this never-before-explored world-let.

Anybody want a peanut? This close up photo of 25143 Itokawa was taken by Hayabusa 1 in 2005. The Mars-crossing asteroid spans just 1,755 feet (535-meters). Credit: JAXA

This is Japan’s second mission to an asteroid. The first – Hayabusa 1 – made a round trip journey to 25143 Itokawa, a rocky asteroid just a third of a mile across some 123 million miles from the Sun, from 2003 to 2010. Even though that mission encountered numerous technical problems including a pointing system failure, a fuel leak and a malfunction of the device used to collect rock samples, engineers babied it back to Earth.

At the time, no one was knew for certain whether any samples had been gathered at all, but upon re-entry, scientists discovered a tiny fraction of material inside the craft landing vehicle. Success!

Artist depiction of Hayabusa 2 in orbit around the dark, carbon-rich asteroid 1999 JU3. Credit: JAXA

“We changed a lot of parts on Hayabusa 2,” said Hitoshi Kuninaka, JAXA’s Hayabusa 2 program manager. “We installed four reaction wheels, and Hayabusa 1 had only three. The sampling system also has some improvements. Our operations software was upgraded for better proximity operations around the asteroid.”

Like the first probe, Hayabusa 2 will propel itself with an ion engine, where ionized (electrified) xenon gas is accelerated through a strong electric field and expelled at high speed to produce a steady thrust. This time around, the engines were upgraded to produce more thrust. A new antenna system will beam back data at four times the previous rate.

One of the four MINERVA II robotic landers that will hop around the asteroid taking pictures and measurements. Credit: JAXA

The spacecraft will arrive at 1999 JU3, which orbits between Earth and Mars, in June 2018. Before dispatching four landing robots, the main spacecraft will study and map the surface from a distance of about 12 miles (20 km).The landers are mobile and able to hop across the asteroid to study its environment from several locations.

Warning – don’t hop too hard! 1999 JU3 is even smaller than Rosetta’s Comet with a gravitational pull 60,000 times weaker than Earth. It wouldn’t be difficult to bounce off the asteroid and not return to the surface for a long time much as what happened to the Philae lander.

Hayabusa 2 will remain at the asteroid for a year and a half, long enough to move in close and use its collection tube to gather rocks from three different locations. In an audacious move, the spacecraft will fire a 2-kilogram (4.4-pound) copper disk into the asteroid to blast out an artificial crater about 10 feet (several meters) across and 3 feet deep. Why? To sample more pristine rocks not exposed to direct solar radiation.

Hayabusa 2 samples the crater floor after the blast, gathering fresh rocks shielded from the damaging effects of cosmic and solar radiation. Credit: Akihiro Ikeshita / JAXA

After the explosion, the spacecraft will swing by and use its sampler arm to fire tiny “bullets” made of the element tantalum into the crater and funnel debris that ricochets up from the surface into its collection tube. Mission planners hope to harvest at least 1/10 of a gram of asteroid dust.

As the spacecraft returns to Earth’s vicinity, it will eject a container with the dust that will drop through the atmosphere and land by parachute in the Australian outback in December 2020.

This is a big week for rocket launches. NASA’s new Orion space capsule is scheduled to launch into orbit on an unmanned test flight at 6:05 a.m. (CST) tomorrow. If all goes well, this could be our first step toward a manned mission to Mars. You can watch the launch live on NASA TV.

House-sized asteroid makes close Earth flyby Monday / See dawn’s ghostly finger

Gianluca Masi used a 17-inch telescope to track the motion of asteroid 2014 UF56 on October 25. The small space rock will pass just 102,000 miles from Earth Monday afternoon CDT. Credit: Gianluca Masi

Discovered only yesterday, Earth-approaching 2014 UF56 will violate our planet’s personal space on Monday October 27th. At around 4 p.m. Central Daylight Time the ~45-foot-wide (14-m) boulder will tumble by at less the half the distance of the Moon.

With 90% of near-Earth asteroids larger than 0.6 miles (1 km) discovered, surveys are now focusing on finding 90% of objects larger than 460 feet (140-m). We have to take it a step at a time because the total number of near-Earth asteroids is in the millions. That’s why objects like 2014 UF56 pop up regularly in surveys each month. Every discovery adds one more piece to the grand puzzle that astronomers have been painstakingly assembling since the very first Earth-approaching asteroid, 433 Eros, was discovered in 1898.

The speedy boulder was found only yesterday. Despite passing so close to Earth, few if any of us will see the flyby with our eyes in a telescope. At brightest, 2014 UF56 will only reach magnitude +16, the limit for a 16-inch telescope, as it zips from Scutum through Capricornus. But you’ll be able to watch its mad dash all the same. Gianluca Masi, an Italian astrophysicist, will have his observatory open for business and stream the close passage live on his Virtual Telescope Project site starting at 2 p.m. CDT (7 p.m. UT) Monday October 27.

A cone of soft light tilts up from the eastern horizon about 2 hours before sunrise on October 22. The planet Jupiter is seen near its tip. Called zodiacal light, it’s sunlight reflecting off dust left by passing comets and asteroid collisions. Now through about November 4 is the best time to see the sight for northern hemisphere observers. Credit: Bob King

Earlier this week I went out before dawn to watch the Orionids, an annual meteor shower that originates from bits of dust and rock shed by Halley’s Comet. Every year during the third week of October we encounter Halley’s dregs and watch them fire up as meteors when they strike the atmosphere 70 miles over our heads. While only a few streaked the sky that morning, my outing coincided with the best display of another much larger phenomenon intimately tied to dust left behind by passing comets – the zodiacal light.

I look forward every fall to seeing the subtle beauty of this large, finger-shaped glow poking up from the eastern horizon. For northern hemisphere observers, it’s best visible before the start of dawn or about 2 hours to 90 minutes before sunrise. Then it towers more than halfway up in the eastern sky titled at about a 60-degree angle to the horizon.

The zodiacal light cone, which is centered on the Sun’s path through the zodiac called the ecliptic, tilts upward in late October reaching up to and even beyond the bright planet Jupiter. Credit: Bob King with Stellarium

To see the zodiacal light, you’ll need a dark, light pollution-free sky view of the eastern sky. and the will to arise “in the darkest hour”. It’s broadest and brightest near its base – similar to the summer Milky Way – but fades and tapers as you lift your gaze toward the bright planet Jupiter, now stationed near its tip.

The phenomenon gets its name from the “zodiac”, a band of a dozen constellations the Sun, Moon and planets pass through during their monthly, yearly and multi-year travels across the sky. When a comet’s orbit takes it within the inner solar system, the Sun vaporizes a portion of its ice, releasing dust and small rocks into space to create the comet’s coma and tail. Much of this dust is left behind in and near the mid-plane of the solar system where it forms a cloud of debris. Illuminated by scattered sunlight, we see it as the skinny-tipped finger of zodiacal light.

Crossed swords of light! The zodiacal light (left) meets the Milky Way in this beautiful image taken on October 1 this year. Though they’re similarly bright and large, the zodiacal light has a smooth texture without the clumpiness that characterizes the Milky Way. Credit: Damian Peach

During fall mornings and spring evenings, northern hemisphere skywatches see that mid-plane tilted up at a steep angle, high above the horizon hazes that would otherwise block the light from view. That’s what makes now an ideal time to set out for a look.

Much of the glowing comet dust will spiral into to the Sun over time and vaporize; a constant stream of comets, old and new, keeps it replenished. Near as I can figure, the zodiacal light is the single, largest visible structure in the solar system.  And to think it’s built of something as insubstantial as comet dust.

Asteroid 2014 RC makes astronomers’ heads spin / Crater appears in Nicaragua

Multiple images of asteroid 2014 RC made with the Lowell Observatory 42-inch Hall telescope showing its motion on September 7, 2014.

Not only did it make a very close approach to Earth yesterday, but astronomers got a better handle on 2014 RC’s size and how fast it spins during the flyby.

The space rock was originally thought to be 60-feet (20-m) across but we now know it’s closer to 40-feet (12-m) or about the size of a school bus and spinning very rapidly. Try one rotation every 15.8 seconds!

That makes 2014 RC the fastest rotating asteroid (by 50%) observed to date. Astronomers using NASA’s Infrared Telescope Facility (IRTF) on September 6 observed the space rock in infrared light to determine its composition. It reflects about much light (25%) as green grass and belongs to the “Sq class” of stony asteroids. Rocky asteroids are the most common kind. Based on its reflectivity, 2014 RC is much brighter than a typical comet and several other classes of asteroids.

The suspect crater near the Managua airport. Credit: AP

In a story begging to be related but isn’t, a purported meteor crater showed up near Managua, Nicaragua’s international airport this weekend. Whatever caused  it, the blast occurred during the early morning of September 6th, 13 hours before 2014 RC’s close flyby, which passed beneath Earth’s orbit anyway. A loud bang was heard and the ground shook, but there are no eyewitness reports or video of a meteor or meteorite fall. The crater is about 40 feet (12-m) across.

The surest way to confirm if a meteorite fell would be to look for fragments in and around the crater. No news yet on that. I’ll update when more information becomes available.