Posted on by Ken Kremer

Revolutionary Dawn Closing in on Asteroid Vesta with Opened Eyes

Virtual Vesta. Taking their best guess, the science team on NASA’s Dawn Asteroid Orbiter have created a series of still images and videos (see below) to simulate what the protoplanet Vesta might look like. The exercise was carried out by mission planners at NASA's Jet Propulsion Laboratory and science team members at the German Aerospace Center and the Planetary Science Institute. Image credit: NASA/JPL-Caltech/ESA/UCLA/DLR/PSI/STScI/UMd

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The excitement is building as NASA’s innovative Dawn spacecraft closes in on its first protoplanetary target, the giant asteroid Vesta, with its camera eyes now wide open. The probe is on target to become the first spacecraft from Earth to orbit a body in the main asteroid belt and is set to arrive about four months from now in late July 2011.

Vesta is the second most massive object in the Asteroid Belt between Mars and Jupiter (map below). Since it is also one of the oldest bodies in our Solar System, scientists are eager to study it and search for clues about the formation and early history of the solar system. Dawn will spend about a year orbiting Vesta. Then it will fire its revolutionay ion thrusters and depart for Ceres, the largest asteroid in our solar system.

Dawn is equipped with three science instruments to photograph and investigate the surface mineralogy and elemental composition of the asteroid. The instruments were provided by the US, Germany and Italy. The spacecraft has just awoken from a six month hibernation phase. All three science instruments have been powered up and reactivated.

Dawn will image about 80 percent of Vesta’s surface at muliple angles with the onboard framing cameras to generate topographical maps. During the year in orbit, the probe will adjust its orbit and map the protoplanet at three different and decreasing altitudes between 650 and 200 kilometers, and thus increasing resolution. The cameras were provided and funded by Germany.

To prepare for the imaging campaign, mission planners from the US and Germany conducted a practice exercise to simulate the mission as though they were mapping Vesta. The effort was coordinated among the science and engineering teams at NASA’s Jet Propulsion Laboratory, the Institute of Planetary Research of the German Aerospace Center (DLR) in Berlin and the Planetary Science Institute in Tuscon, Ariz.

Simulated Vesta from the South Pole
This image shows the scientists' best guess to date of what the surface of the protoplanet Vesta might look like from the south pole, as projected onto a sphere 250 kilometers (160 miles) in radius. It was created as part of an exercise for NASA's Dawn mission involving mission planners at NASA's Jet Propulsion Laboratory and science team members at the Planetary Science Institute in Tuscon, Ariz. Credit: NASA/JPL-Caltech/UCLA/PSI

“We won’t know what Vesta really looks like until Dawn gets there,” said Carol Raymond in a NASA statement. Raymond is Dawn’s deputy principal investigator, based at JPL, who helped orchestrate the activity. “But we needed a way to make sure our imaging plans would give us the best results possible. The products have proven that Dawn’s mapping techniques will reveal a detailed view of this world that we’ve never seen up close before.”

Two teams worked independently and used different techniques to derive the topographical maps from the available data sets. The final results showed only minor differences in spatial resolution and height accuracy.

Using the best available observations from the Hubble Space Telescope and ground based telescopes and computer modeling techniques, they created maps of still images and a rotating animation (below) showing their best guess as to what Vesta’s surface actually looks like. The maps include dimples, bulges and craters based on the accumulated data to simulate topography and thus give a sense of Virtual Vesta in three dimensions (3 D).

“Working through this exercise, the mission planners and the scientists learned that we could improve the overall accuracy of the topographic reconstruction, using a somewhat different observation geometry,” said Nick Mastrodemo, Dawn’s optical navigation lead at JPL. “Since then, Dawn science planners have worked to tweak the plans to implement the lessons of the exercise.”

Dawn launch on September 27, 2007 by a Delta II rocket from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer
Of course no one will know how close these educated guesses come to matching reality until Dawn arrives at Vesta.

The framing camera system consists of two identical cameras developed and built by the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany and the German Aerospace Center (DLR) in Berlin.

“The camera system is working flawlessly. The dry run was a complete success,” said Andreas Nathues, lead investigator for the framing camera at the Max Planck Institute in Katlenburg-Lindau, Germany.

Since the probe came out of hibernation, the mechanical and electrical components were checked out in mid March and found to be in excellent health and the software was updated.

Dawn is a mission of many firsts.

Dawn spacecraft under construction in Cleanroom.
Picture shows close up view of two science instruments;
The twin Framing Cameras at top (white rectangles) and VIR Spectrometer at right. Credit: Ken Kremer
The spacecraft is NASA’s first mission specifically to the Asteroid Belt. It will become the first mission to orbit two solar system bodies.

The revolutionary Dawn mission is powered by exotic ion propulsion which is vastly more efficient than chemical propulsion thrusters. Indeed the ability to orbit two bodies in one mission is only enabled via the use of the ion engines fueled by xenon gas.

Vesta and Ceres are very different worlds that orbit between Mars and Jupiter. Vesta is rocky and may have undergone volcanism whereas Ceres is icy and may even harbor a subsurface ocean conducive to life.

Dawn will be able to comparatively investigate both celestial bodies with the same set of science instruments and try to unlock the mysteries of the beginnings of our solar system and why they are so different.

Dawn is part of NASA’s Discovery program and was launched in September 2007 by a Delta II rocket from Cape Canaveral Air Force Station, Florida.

Virtual Vesta in 2 D.
This image shows a model of the protoplanet Vesta, using scientists' best guess to date of what the surface of the protoplanet might look like. The images incorporate the best data on dimples and bulges of Vesta from ground-based telescopes and NASA's Hubble Space Telescope. The cratering and small-scale surface variations are computer-generated, based on the patterns seen on the Earth's moon, an inner solar system object with a surface appearance that may be similar to Vesta. Credit: NASA/JPL-Caltech/UCLA/PSI
Virtual Vesta in 3 D.
This anaglyph -- best viewed through red-blue glasses -- shows a 3-D model of the protoplanet Vesta, using scientists' best guess to date of what the surface of the protoplanet might look like. Image credit: NASA/JPL-Caltech/UCLA/PSI
Dawn Spacecraft current location approaching Asteroid Vesta on March 21, 2011
Posted on by Nancy Atkinson

Equipment to Study Hayabusa’s Asteroid Samples Damaged in Japan Earthquake

Magnified view of a dust particle in the Hayabusa canister. Credit: JAXA

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The large particle accelerator being used in to analyze the asteroid samples returned by the Hayabusa spacecraft was damaged by the March 11 earthquake in Japan, but the high energy accelerator at the KEK particle-physics laboratory will be repaired, according to this report on a Japanese website. An announcement on the KEK website said that all accelerators and experimental devices were stopped immediately “after the first shake” of the historic earthquake. “We have confirmed the radiation safety, and no hazard to the environment has been reported,” the announcement said. “Also there are no reports of casualties on both Tsukuba and Tokai campuses.” Tsukuba is in the mid-latitudes of Japan, about 50 km from Tokyo.

Apparently, the tiny asteroid particles are safe, but an official at KEK was quoted as saying (via Google Translate) “The accelerator needs to be adjusted very precisely. To suffer this much, but it takes time to recover, want to lose to the earthquake recovery.”

But the repairs to the accelerator may take a back seat to the current situation in Japan. The city of Tsukuba is going to take in refugees from Fukushima prefecture, where the heavily damaged nuclear reactor is located and the KEK facilities will provide support for radiation screening for the refugees upon their arrival.

This photo shows some of the damage to the Tsukuba Space Center in Tsukuba, Japan, the main space center for the country's JAXA agency, from the 8.9-magnitude earthquake that struck on March 11, 2011. Credit: collectSPACE.com

Tsukuba is also home to the space center that oversees Japan’s Kibo laboratory on the International Space Station, as well the JAXA’s unmanned cargo ships that deliver supplies on orbit. The space center was slightly damaged, and for awhile NASA’s Mission Control in Houston took over operations remotely. According to Robert Pearlman on collectSPACE, several of the Japanese flight control team members and flight directors from the Tsukuba Space Center happened to be in Houston when the quake struck, preparing for the Expedition 27 crew rotation, as astronaut Satoshi Furukawa will be heading the ISS in May. However, operations from the mission control rooms were resumed at 4:00 p.m. on March 22, 2011.

JAXA Flight Control Team (JFCT) resuming the Kibo operations at the Mission Control Room (MCR). Credit: JAXA

Another center, the Kakuda Space Center, located in the Miyagi region close to the most serious effects of the earthquake and tsunami, was heavily damaged, and is closed with no timetable for reopening. The Kakuda center is JAXA’s rocket development and testing center and is Japan’s equivalent of the Stennis Space Center in Mississippi.

JAXA’s Tsukuba Space Center located in Tsukuba Science City,

Additionally, the ground-breaking ceremony for a new type of particle smasher known as a “super B factory” in Tsukuba has been postponed. Japan had invested $100 million to transform the KEKB collider in Tsukuba, into a Super KEKB, which will smash electrons into positrons at 40 times the rate of the current accelerator.
Just before the quake, the Japanese Space Agency JAXA had announced they are planning a second Hayabusa mission with an explosive twist. The second mission to an asteroid probe will include an impactor that detonates an explosive on the asteroid’s surface, similar to the Deep Impact mission.

The launch was tentatively planned for launch in 2014, heading to a space rock catalogued as 162173 1999 JU3. The probe would land on the surface and, collect samples before and after the impactor blasts its way to the asteroid’s interior.

Despite the problems Hayabusa encountered along its arduous journey to and from asteroid Itokawa –including thruster, communications, gyro and fuel-leak problems, as well as uncertainty whether the probe landed on the asteroid – JAXA and the Japanese people were buoyed by the success of Hayabusa.

It is not clear how the tragic earthquake and tsunami will affect future space missions for Japan, but obviously the country has more important issues ahead of them. May the spirit of the Japanese people be lifted again.

Sources: NHK,, KEK , collectSPACE, Moon and Back, JAXA

Hat tip to Emily Lakdawalla via Twitter.

Posted on by Nancy Atkinson

Astronomers Continue to Monitor Asteroid Apophis

Apophis (circled) in a composite of five exposures taken on January 31 with the University of Hawaii 2.2-meter telescope on Mauna Kea. Image by D. Tholen, M. Micheli, G. Elliott, UH Institute for Astronomy.

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Asteroid Apophis continues to be an object of interest for astronomers. Even though the possibility of an Earth impact by the now-famous asteroid has been ruled out during its upcoming close encounter on April 13, 2029, this close flyby will significantly change Apophis’s orbit, and astronomers are uncertain how that could affect future encounters with our planet. For that reason, astronomers have been eager to obtain new data to further refine the details of the 2029 encounter. However, for three years, the asteroid’s orbit had it “hiding” behind the Sun, but it has now emerged. This newest image of Apophis was taken on January 31, 2011, using the University of Hawaii’s 2.2-meter telescope on Mauna Kea, and astronomers from UH at Manoa say they will make repeated observations of this potentially dangerous near-Earth asteroid.

Astronomers measure the position of an asteroid by comparing with the known positions of stars that appear in the same image as the asteroid. As a result, any tiny error in the catalog of star positions, due for example to the very slow motions of the stars around the center of our Milky Way galaxy, can affect the measurement of the position of the asteroid.

“We will need to repeat the observation on several different nights using different stars to average out this source of imprecision before we will be able to significantly improve the orbit of Apophis and therefore the details of the 2029 close approach and future impact possibilities,” said astronomer David Tholen, one of the co-discoverers of Apophis, who made the latest observations along with graduate students Marco Micheli and Garrett Elliott.

They obtained the new images when the 270-meter (900-foot) diameter asteroid was less than 44 degrees from the sun and about a million times fainter than the faintest star that the average human eye can see without optical aid.

The astronomers will be taking advantage of Apophis’s position for the next few months, as its elliptical orbit around the Sun will take it back into the sun’s glare this summer, making observations – and measurements of its position – impossible. However, in 2012, Apophis will again become observable for approximately nine months. In 2013, the asteroid will pass close enough to Earth for ultraprecise radar signals to be bounced off its surface.

“Radar observations are important because we can estimate orbital parameters and provides us lots of information about an asteroid’s surface features and internal structure, and how they may have formed,” said Lance Benner, an astronomer at JPL, who specializes in radar imaging of near-Earth asteroids. “We need to know these things if we are going to deflect one of these.” Speaking at the American Geophysical Union conference in 2009, Benner said radar is the most powerful astronomical technique for both finding new asteroids and measuring their orbits.

“We can measure their velocity to less than 1mm per second, and do this up to 20 million kilometers from earth. Radar helps us compute the trajectory much farther into the future – even up to 300 years, giving us much more advance notice.” Benner said they can routinely image asteroids at 7.5 meters per pixel, and a new system at the Goldstone radar facility will be able to get the resolution down to 1 meter per pixel.

On April 13, 2029, Apophis will come closer to Earth than the geosynchronous communications satellites that orbit Earth at an altitude of about 36,000 km (22,000 miles). Astronomers say Apophis will then be briefly visible to the naked eye as a fast-moving starlike object.

Source: University of Hawaii Institute for Astronomy

Posted on by Nancy Atkinson

New Record: Telescope Finds 19 Near-Earth Asteroids in One Night

Richard Wainscoat (left) and Marco Micheli study one of the near-Earth asteroids found on January 29. The asteroid is the roundish dot near Wainscoat’s finger. Photo by Karen Teramura

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From a University of Hawaii Institute for Astronomy press release:

The Pan-STARRS PS1 telescope on Haleakala, Maui, discovered 19 near-Earth asteroids on the night of January 29, the most asteroids discovered by one telescope on a single night.

“This record number of discoveries shows that PS1 is the world’s most powerful telescope for this kind of study,” said Nick Kaiser, head of the Pan-STARRS project. “NASA and the U.S. Air Force Research Laboratory’s support of this project illustrates how seriously they are taking the threat from near-Earth asteroids.”

Pan-STARRS software engineer Larry Denneau spent that Saturday night in his University of Hawaii at Manoa office in Honolulu processing the PS1 data as it was transmitted from the telescope over the Internet. During the night and into the next afternoon, he and others came up with 30 possible new near-Earth asteroids.
Asteroids are discovered because they appear to move against the background of stars. To confirm asteroid discoveries, scientists must carefully re-observe them several times within 12-72 hours to define their orbits, otherwise they are likely to be “lost.”

Denneau and colleagues quickly sent their discoveries to the Minor Planet Center in Cambridge, Mass., which collects and disseminates data about asteroids and comets, so that other astronomers can re-observe the objects.

“Usually there are several mainland observatories that would help us confirm our discoveries, but widespread snowstorms there closed down many of them, so we had to scramble to confirm many of the discoveries ourselves,” noted Institute for Astronomy astronomer Richard Wainscoat.

Wainscoat, astronomer David Tholen, and graduate student Marco Micheli spent the next three nights searching for the asteroids using telescopes at Mauna Kea Observatories, Hawaii.

On Sunday night, they confirmed that two of the asteroids were near-Earth asteroids before snow on Mauna Kea forced the telescopes to close. On Monday night, they confirmed nine more before fog set in.
On Tuesday night, they searched for four, but found only one. After Tuesday, the remaining unconfirmed near-Earth asteroids had moved too far to be found again.

Telescopes in Arizona, Illinois, Italy, Japan, Kansas, New Mexico, and the United Kingdom, and the Faulkes Telescope on Haleakala also helped to confirm seven of the discoveries.

Two of the asteroids, it turns out, have orbits that come extremely close to Earth’s. There is no immediate danger, but a collision in the next century or so, while unlikely, cannot yet be ruled out. Astronomers will be paying close attention to these objects.

Posted on by Nancy Atkinson

Small Asteroid Just Buzzed Earth

If you felt a sudden breeze at about 19:40 GMT (2:40 pm EST), it was probably from a small asteroid that came extremely close to the Earth today (Feb. 4, 2011). The object, officially designated 2011 CQ1, is fairly small — about 2-3 meters (6.5 -10 ft) wide — and at closest approach it came within 11,855 km (7,366 miles) or about 0.03 lunar distances (LD), or 0.00008 astronomical units (AU). Yep, that’s pretty close.

Richard Kowalski with the Catalina Sky Survey discovered this object early today. The image above is from Giovanni Sostero & Ernesto Guido who made remote follow-up observations to confirm with the Tzec Maun Observatory in New Mexico.

There was no chance this object was going to hit Earth, but it did come well within what is known as the Clarke Belt among geosynchronous satellites.

Find out more about the path this object is taking at Remanzacco Observatory in Italy.

Info on the Minor Planet Center website about 2011 CQ1.

Astronomer Bill Gray calculated a transit line plot showing the path over South America. You can see the charts here:

http://www.projectpluto.com/cq1.png

http://www.projectpluto.com/cq1a.png

And if you are an astrophotographer, let us know if you capture any images of 2011 CQ1.

Posted on by Nancy Atkinson

Mission Complete: NEOWISE Concludes Hunt for Near-Earth Objects

During its one-year mission, NASA's Wide-field Infrared Survey Explorer, or WISE, mapped the entire sky in infrared light. Among the multitudes of astronomical bodies that have been discovered by the NEOWISE portion of the WISE mission are 20 comets. Image credit: NASA/JPL-Caltech/UCLA

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The WISE spacecraft has completed a special mission called NEOWISE, looking for small bodies in the solar system, and has discovered a plethora of previously unknown objects. The NEOWISE mission found 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs). More data from NEOWISE also have the potential to reveal a brown dwarf even closer to us than our closest known star, Proxima Centauri, if such an object does exist. Likewise, if there is a hidden gas-giant planet in the outer reaches of our solar system, data from WISE and NEOWISE could detect it.

“WISE has unearthed a mother lode of amazing sources, and we’re having a great time figuring out their nature,” said Edward (Ned) Wright, the principal investigator of WISE at UCLA.

“Even just one year of observations from the NEOWISE project has significantly increased our catalog of data on NEOs and the other small bodies of the solar systems,” said Lindley Johnson, NASA’s program executive for the NEO Observation Program.

The NEOs are asteroids and comets with orbits that come within 45 million kilometers (28 million miles) of Earth’s path around the sun.

The NEOWISE mission made use of the the WISE spacecraft, the Wide-field Infrared Survey Explorer that launched in December 2009. WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth.

However, in early October 2010, after completing its prime science mission, the spacecraft ran out of the frozen coolant that keeps its instrumentation cold. But two of its four infrared cameras remained operational, which were still optimal for asteroid hunting, so NASA extended the NEOWISE portion of the WISE mission by four months, with the primary purpose of hunting for more asteroids and comets, and to finish one complete scan of the main asteroid belt.

Now that NEOWISE has successfully completed a full sweep of the main asteroid belt, the WISE spacecraft will go into hibernation mode and remain in polar orbit around Earth, where it could be called back into service in the future.

In addition to discovering new asteroids and comets, NEOWISE also confirmed the presence of objects in the main belt that had already been detected. In just one year, it observed about 153,000 rocky bodies out of approximately 500,000 known objects. Those include the 33,000 that NEOWISE discovered.

NEOWISE also observed known objects closer and farther to us than the main belt, including roughly 2,000 asteroids that orbit along with Jupiter, hundreds of NEOs and more than 100 comets.

These observations will be key to determining the objects’ sizes and compositions. Visible-light data alone reveal how much sunlight reflects off an asteroid, whereas infrared data is much more directly related to the object’s size. By combining visible and infrared measurements, astronomers also can learn about the compositions of the rocky bodies — for example, whether they are solid or crumbly. The findings will lead to a much-improved picture of the various asteroid populations.

NEOWISE took longer to survey the whole asteroid belt than WISE took to scan the entire sky because most of the asteroids are moving in the same direction around the sun as the spacecraft moves while it orbits Earth. The spacecraft field of view had to catch up to, and lap, the movement of the asteroids in order to see them all.

“You can think of Earth and the asteroids as racehorses moving along in a track,” said Amy Mainzer, the principal investigator of NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We’re moving along together around the sun, but the main belt asteroids are like horses on the outer part of the track. They take longer to orbit than us, so we eventually lap them.”

NEOWISE data on the asteroid and comet orbits are catalogued at the NASA-funded International Astronomical Union’s Minor Planet Center, a clearinghouse for information about all solar system bodies at the Smithsonian Astrophysical Observatory in Cambridge, Mass. The science team is analyzing the infrared observations now and will publish new findings in the coming months.

The first batch of observations from the WISE mission will be available to the public and astronomical community in April.

Source: NASA

Posted on by Nancy Atkinson

Asteroid Apophis in the News Again

Annimation of Apophis. Image Credit: Osservatorio Astronomico Sormano

It must have been a slow news day in Russia yesterday (actually – and unfortunately — it wasn’t)… as headlines from one of Russia’s leading news agencies, Ria Novosti, proclaimed, “Russian Astronomers Predict Apophis-Earth Collision in 2036.” But reading the article a little further, the astronomer, Leonid Sokolov of St. Petersburg State University says the chance of a collision in 2036 is extremely slim, which is exactly what NASA’s Near-Earth Object Program has been saying for several years. So, just to be clear, there is no new information or changes in understanding Apophis’ orbit. Here are the facts:

Continue reading “Asteroid Apophis in the News Again”

Posted on by Nancy Atkinson

More Asteroids Could Have Made Life’s Ingredients

This artist's concept uses hands to illustrate the left and right-handed versions of the amino acid isovaline. Credit: NASA/Mary Pat Hrybyk-Keith

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From a NASA press release:

A wider range of asteroids were capable of creating the kind of amino acids used by life on Earth, according to new NASA research. Amino acids are used to build proteins, which are used by life to make structures like hair and nails, and to speed up or regulate chemical reactions. Amino acids come in two varieties that are mirror images of each other, like your hands. Life on Earth uses the left-handed kind exclusively. Since life based on right-handed amino acids would presumably work fine, scientists are trying to find out why Earth-based life favored left-handed amino acids.

In March, 2009, researchers at NASA’s Goddard Space Flight Center in Greenbelt, Md., reported the discovery of an excess of the left-handed form of the amino acid isovaline in samples of meteorites that came from carbon-rich asteroids. This suggests that perhaps left-handed life got its start in space, where conditions in asteroids favored the creation of left-handed amino acids. Meteorite impacts could have supplied this material, enriched in left-handed molecules, to Earth. The bias toward left-handedness would have been perpetuated as this material was incorporated into emerging life.

In the new research, the team reports finding excess left-handed isovaline (L-isovaline) in a much wider variety of carbon-rich meteorites. “This tells us our initial discovery wasn’t a fluke; that there really was something going on in the asteroids where these meteorites came from that favors the creation of left-handed amino acids,” says Dr. Daniel Glavin of NASA Goddard. Glavin is lead author of a paper about this research published online in Meteoritics and Planetary Science January 17.

This is a photo of a carbon-rich meteorite analyzed in the study. Credit: Antarctic Meteorite Laboratory/NASA Johnson Space Center

“This research builds on over a decade of work on excesses of left-handed isovaline in carbon-rich meteorites,” said Dr. Jason Dworkin of NASA Goddard, a co-author on the paper.

“Initially, John Cronin and Sandra Pizzarello of Arizona State University showed a small but significant excess of L-isovaline in two CM2 meteorites. Last year we showed that L-isovaline excesses appear to track with the history of hot water on the asteroid from which the meteorites came. In this work we have studied some exceptionally rare meteorites which witnessed large amounts of water on the asteroid. We were gratified that the meteorites in this study corroborate our hypothesis,” explained Dworkin.

L-isovaline excesses in these additional water-altered type 1 meteorites (i.e. CM1 and CR1) suggest that extra left-handed amino acids in water-altered meteorites are much more common than previously thought, according to Glavin. Now the question is what process creates extra left-handed amino acids. There are several options, and it will take more research to identify the specific reaction, according to the team.

However, “liquid water seems to be the key,” notes Glavin. “We can tell how much these asteroids were altered by liquid water by analyzing the minerals their meteorites contain. The more these asteroids were altered, the greater the excess L-isovaline we found. This indicates some process involving liquid water favors the creation of left-handed amino acids.”

Another clue comes from the total amount of isovaline found in each meteorite. “In the meteorites with the largest left-handed excess, we find about 1,000 times less isovaline than in meteorites with a small or non-detectable left-handed excess. This tells us that to get the excess, you need to use up or destroy the amino acid, so the process is a double-edged sword,” says Glavin.

Whatever it may be, the water-alteration process only amplifies a small existing left-handed excess, it does not create the bias, according to Glavin. Something in the pre-solar nebula (a vast cloud of gas and dust from which our solar system, and probably many others, were born) created a small initial bias toward L-isovaline and presumably many other left-handed amino acids as well.

One possibility is radiation. Space is filled with objects like massive stars, neutron stars, and black holes, just to name a few, that produce many kinds of radiation. It’s possible that the radiation encountered by our solar system in its youth made left-handed amino acids slightly more likely to be created, or right-handed amino acids a bit more likely to be destroyed, according to Glavin.

It’s also possible that other young solar systems encountered different radiation that favored right-handed amino acids. If life emerged in one of these solar systems, perhaps the bias toward right-handed amino acids would be built in just as it may have been for left-handed amino acids here, according to Glavin.

The research was funded by the NASA Astrobiology Institute (NAI), which is administered by NASA’s Ames Research Center in Moffett Field, Calif.; the NASA Cosmochemistry program, the Goddard Center for Astrobiology, and the NASA Post Doctoral Fellowship program. The team includes Glavin, Dworkin, Dr. Michael Callahan, and Dr. Jamie Elsila of NASA Goddard.

Posted on by Ken Kremer

Deep Space Radar Unveils Rotating Asteroid 2010 JL33

A radar image of asteroid 2010 JL33, generated from data taken by NASA's Goldstone Solar System Radar on Dec. 11 and 12, 2010. Image credit: NASA/JPL-Caltech

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Intriguing details about the physical properties and characteristics of a recently discovered asteroid have just been unveiled in amazing images obtained using a large radar dish in California. The radar dish serves as a key component of NASA’s Deep Space Network (DSN). The Near Earth asteroid, dubbed 2010 JL33, was imaged by radar on Dec. 11 and 12, 2010 at NASA’s Goldstone Solar System Radar in California’s Mojave Desert when a close approach to Earth offered an outstanding opportunity for high quality science.

Asteroids studies have taken on significantly increased importance at NASA ever since President Obama decided to cancel the Constellation ‘Return to the Moon’ program and redirect NASA’s next human spaceflight goal to journeying to an Asteroid by around 2025.

Update: Orbital diagram added below
A sequence of 36 amazingly detailed images has been assembled into a short movie (see below) by the science team at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The movie shows about 90 percent of one rotation.

The data gathered by radar revealed that the asteroid measures roughly 1.8 kilometers (1.1 miles) in diameter and rotates once every nine hours.

Orbital diagram of Asteroid 2010 JL33 shows location as of Jan 14, 2011. Credit: NASA
click to enlage all images

“Asteroid 2010 JL33 approached within 17 Earth-Moon distances [some 7 million km] in December 2010 and offered an outstanding opportunity to study it with radar,” said Lance Benner, a scientist at JPL who studies asteroids.

“To get detailed radar images, an asteroid must be close to Earth,” Benner told me, for Universe Today.

The object was only discovered on May 6 by the Mount Lemmon Survey in Arizona. The radar observations were led by a team headed by JPL scientist Marina Brozovic.

Video Caption: While safely passing Earth, NASA’s Goldstone Solar System Radar captured the rotation of asteroid 2010 JL33 — an irregular, elongated object roughly 1.8 kilometers (1.1) miles wide. The video consists of 36 frames.

“The radar images we got enabled us to estimate the asteroid’s size, rotation period, and to see features on its surface, most notably, the large concavity that appears as a dark region in the collage,” Benner elaborated.

“It was discovered so recently that little else is known about it.”

The object was revealed to be elongated and irregularly shaped.

70-meter diameter NASA Deep Space Network (DSN) antenna at Goldstone, California.

The 70-meter (230-foot) diameter antenna is the largest, and therefore most sensitive, DSN antenna, and is capable of tracking a spacecraft travelling more than 16 billion kilometers (10 billion miles) from Earth.
The surface of the 70-meter reflector must remain accurate within a fraction of the signal wavelength, meaning that the precision across the 3,850-square-meter (41,400 sq. ft.) surface is maintained within one centimeter (0.4 in.). Credit: NASA


The large concavity is clearly visible in the images and may be an impact crater. It took about 56 seconds for the radio signals from the 70-meter (230-foot) diameter Goldstone radar dish to make the roundtrip from Earth to the asteroid and back to Earth again.

“When we get deeper into our analysis of the data, we will use the images to estimate the three-dimensional shape of the asteroid as well,” Benner added.

Benner belongs to a team that is part of a long-term NASA program to study asteroid physical properties and to improve asteroid orbits using radar telescopes at Goldstone and also at the Arecibo Observatory in Puerto Rico. The 1,000-foot-diameter (305 meters) Arecibo radar dish antenna is operated by the National Science Foundation.

“Each close approach by an asteroid provides an important opportunity to study it, so we try to exploit as many such opportunities as possible to investigate the physical properties of many asteroids. In the bigger picture, this helps us understand how the asteroids formed,” Benner told me.

“Asteroid 2010 JL33 is in an elongated orbit about the Sun. On average, it’s about 2.7 times farther from the Sun than the Earth is, but its distance from the Sun varies from 0.7 to 4.6 times that of the Earth.” That takes the asteroid nearly out to Jupiter at Aphelion. It takes about 4.3 years to complete one orbit around the sun.

But, there’s no need to fret about disaster scenarios. “The probability of impact with Earth is effectively zero for the foreseeable future,” Benner explained.

“On rare occasions it approaches closely to Vesta,” he said. Vesta is the second most massive asteroid and will be visited for the first time by NASA’s Dawn spacecraft later this year.

In addition to the ground based radar imaging, the tiny space rock was investigated by an Earth orbiting telescope.

“This asteroid was also studied by NASA’s Wide-field Infrared Survey Explorer (WISE) spacecraft,” according to Benner. “Our observations will help WISE scientists calibrate their results because we provided an independent means to estimate the size of this object.”

More at this JPL press release. The NASA-JPL Near-Earth Object Program website has an interactive map that allows you to see the asteroid’s position at any time you desire. Go to here

To see the trajectory of any other near-Earth asteroid, go to here

For more information about asteroid radar research, go to here

Information about the Deep Space Network is here

Posted on by Jon Voisey

Did GD61 Eat a Planetessimal?

Dusty debris around an old white dwarf star (NASA)

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The primary method by which astronomers hope to study exoplanet atmospheres is by detecting their absorption spectra as they transit their parent stars. However, another way would be to detect the signal of the atmospheric components in the atmosphere of a star that recently cannibalized a planet or other large body. White dwarfs offer an excellent class of stars on which to use this method since convection will pull heavy elements down more rapidly, leaving surfaces with near pristine hydrogen and helium photospheres. The presence of other elements would indicate recent accretion. This method has been used on several white dwarfs previously, but a new study reexamines data from a 2008 paper, adding their own data on the white dwarf GD61 to propose that the star isn’t just eating dust and small bodies, but a sizable one, likely containing water.

Data for the project were taken in 2009 using the SPITZER telescope. One of the first clues to the presence of a recent case of cannibalism was the presence of warm dust within the Roche limit of the star. This disc did not extend more than 26 stellar radii from the star, leading the team to suspect that this was not simply a large scale disc feeding the star with rocky materials, but an object that had fallen inwards to be tidally torn apart.

To support this, the new team used the Keck I telescope on Mauna Kea with the HIRES spectograph to analyze the spectrum. The findings from this confirmed the previous study that, in order of decreasing abundance, the star contained helium, hydrogen, oxygen, silicon, and iron. Based on the amount of material present in the spectrum and estimated convection rates for such stars, the team concluded that, if the disc were created by a single body, it would have been an asteroid at least 100 km in diameter. So why should the team expect that it was a single body as opposed to many smaller ones?

The key lies in the relative amount of detected elements. For GD61, oxygen was the most abundant element not typically present in white dwarf atmospheres. In fact, its presence far outweighed the other elements such that, even if all of it had been previously bound to the silicon, iron, carbon, and other trace elements, there would still be an inexplicable excess. This oxygen would necessarily have been combined into some molecule or have dissipated during the red giant phase. The only way the team could account for its presence would be to have it wrapped up in water (H2O) which, after disassociation, would allow the hydrogen to blend in the the expected hydrogen already present. Since water readily sublimates without sufficient pressures, the team notes that a large number of small bodies would be unable to bury the water deep enough to keep it from escaping previously, that the best explanation would be a large body which could shield water inside it during the previous red giant phase.

The evidence of water rich asteroids speaks to the formation of our own solar system because it provides a delivery mechanism for water to our planet beyond direct accretion. Water rich asteroids and comets would likely have supplemented our supply. Indeed, Ceres, the largest known asteroid in our solar system, is suspected to harbor as much as 25% of its mass in water.