Giant telescopes pair up to image near-Earth asteroid - video

NASA scientists used Earth-based radar to produce these sharp views - an image montage and a movie sequence, of the asteroid designated '2014 HQ124' on June 8, 2014. 

Credit: NASA /JPL-Caltech /Arecibo Observatory /USRA /NSF

NASA scientists using Earth-based radar have produced sharp views of a recently discovered asteroid as it slid silently past our planet.

Captured on June 8, 2014, the new views of the object designated "2014 HQ124" are some of the most detailed radar images of a near-Earth asteroid ever obtained.

An animation of the rotating asteroid and a collage of the images are available below.

The radar observations were led by scientists Marina Brozovic and Lance Benner of NASA's Jet Propulsion Laboratory, Pasadena, California.

The JPL researchers worked closely with Michael Nolan, Patrick Taylor, Ellen Howell and Alessondra Springmann at Arecibo Observatory in Puerto Rico to plan and execute the observations.

According to Benner, 2014 HQ124 appears to be an elongated, irregular object that is at least 1,200 feet (370 meters) wide on its long axis.

"This may be a double object, or 'contact binary,' consisting of two objects that form a single asteroid with a lobed shape," he said.

The images reveal a wealth of other features, including a puzzling pointy hill near the object's middle, on top as seen in the images.

The 21 radar images were taken over a span of four-and-a-half hours. During that interval, the asteroid rotated a few degrees per frame, suggesting its rotation period is slightly less than 24 hours.

At its closest approach to Earth on June 8, the asteroid came within 776,000 miles (1.25 million kilometers), or slightly more than three times the distance to the moon.

Scientists began observations of 2014 HQ124 shortly after the closest approach, when the asteroid was between about 864,000 miles and 902,000 miles (1.39 million kilometers and 1.45 million kilometers) from Earth.

Each image in the collage and movie represents 10 minutes of data.


Credit: NASA

The new views show features as small as about 12 feet (3.75 meters) wide. This is the highest resolution currently possible using scientific radar antennas to produce images.

Such sharp views for this asteroid were made possible by linking together two giant radio telescopes to enhance their capabilities.

To obtain the new views, researchers paired the 230-foot (70-meter) Deep Space Network antenna at Goldstone, California, with two other radio telescopes, one at a time.

Using this technique, the Goldstone antenna beams a radar signal at an asteroid and the other antenna receives the reflections.

The technique dramatically improves the amount of detail that can be seen in radar images.

To image 2014 HQ124, the researchers first paired the large Goldstone antenna with the 1,000-foot (305-meter) Arecibo radio telescope in Puerto Rico.

They later paired the large Goldstone antenna with a smaller companion, a 112-foot (34-meter) antenna, located about 20 miles (32 kilometers) away.

A recent equipment upgrade at Arecibo enabled the two facilities to work in tandem to obtain images with this fine level of detail for the first time.

"By itself, the Goldstone antenna can obtain images that show features as small as the width of a traffic lane on the highway," said Benner.

"With Arecibo now able to receive our highest-resolution Goldstone signals, we can create a single system that improves the overall quality of the images."

The first five images in the new sequence, the top row in the collage, represent the data collected by Arecibo, and are 30 times brighter than what Goldstone can produce observing on its own.

Near-Earth asteroid is really a comet

The image displays Don Quixote's orbit. Credit: Josh Emery

Some things are not always what they seem—even in space. For 30 years, scientists believed a large near-Earth object was an asteroid.

Now, an international team including Joshua Emery, assistant professor of earth and planetary sciences at the University of Tennessee, Knoxville, has discovered it is actually a comet.

Called 3552 Don Quixote, the body is the third largest near-Earth object—mostly rocky bodies, or asteroids, that orbit the Sun in the vicinity of Earth.

About 5 percent of near-Earth objects are thought to be "dead" comets that have shed all the water and carbon dioxide in the form of ice that give them their coma—a cloud surrounding the comet nucleus—and tail.

The team found that Don Quixote is neither. It is, in fact, an active comet, thus likely containing water ice and not just rocks.

The finding will be presented at the European Planetary Science Congress 2013 in London, Sept. 10. The discovery could hold implications for the origin of water on Earth.

Joshua Emery

"Don Quixote has always been recognized as an oddball," said Emery. "Its orbit brings it close to Earth, but also takes it way out past Jupiter."

"Such a vast orbit is similar to a comet's, not an asteroid's, which tend to be more circular—so people thought it was one that had shed all its ice deposits."

Using the Spitzer Space Telescope operated by the Jet Propulsion Laboratory at the California Institute of Technology (CalTech) under contract with NASA, the team, led by Michael Mommert of Northern Arizona University, re-examined images of Don Quixote from 2009 when it was in the part of its orbit closest to the Sun, and found it had a coma and a faint tail.

Emery also reexamined images from 2004, when it was at its farthest distance from the sun, and determined that the surface is composed of silicate dust, which is similar to comet dust.

He also determined that Don Quixote did not have a coma or tail at this distance, which is common for comets because they need the sun's radiation to form the coma and the sun's charged particles to form the tail.

The researchers also confirmed Don Quixote's size and the low, comet-like reflectivity of its surface.

"The power of the Spitzer telescope allowed us to spot the coma and tail, which was not possible using optical telescopes on the ground," said Emery.

"We now think this body contains a lot of ice, including carbon dioxide and/or carbon monoxide ice, rather than just being rocky."

This discovery implies that carbon dioxide and water ice might be present within other near-Earth asteroids, as well.

It also may have implications for the origins of water on Earth as comets may be the source of at least some of it, and the amount on Don Quixote represents about 100 billion tons of water—roughly the same amount that can be found in Lake Tahoe, California's.

Near-Earth Asteroid Captured by Amateur Astronomer - Video

Gianluca Masi (www.virtualtelescope.eu) captured telescope video of asteroid 2012 QG42 on September 11, 2012. It will pass 1,739,839 miles from Earth on September 14th and is about the size of three football fields. Credit: Gianluca Masi