Subscribe free to our newsletters via your
. 24/7 Space News .




IRON AND ICE
Getting the Right Spin on a Close-Passing Asteroid
by Staff Writers
Washington DC (SPX) Feb 14, 2013


How the Yarkovsky Effect slows an asteroid's orbital motion; opposite rotation direction would speed up the orbital motion. Credit: Alexandra Bolling, NRAO/AUI/NSF. For a larger version of this image please go here.

The record-setting close approach of an asteroid on Feb. 15 is an exciting opportunity for scientists, and a research team will use National Radio Astronomy Observatory (NRAO) and NASA telescopes to gain a key clue that will help them predict the future path of this nearby cosmic neighbor.

A 150-foot-wide asteroid called 2012 DA14, discovered just a year ago, will pass only 17,200 miles above the Earth on Feb. 15. That's closer than the geosynchronous communication and weather satellites. While the object definitely will not strike the Earth, this is a record close approach for an object of this size. Astronomers around the world are preparing to take advantage of the event to study the asteroid.

A team including NRAO astronomer Michael Busch will use a novel observing technique to determine which way the space rock is spinning as it speeds on its orbit through the solar system. The direction of its spin is an important factor in predicting how the object's orbit will change over time.

"Knowing the direction of spin is essential to accurately predicting its future path, and thus determining just how close it will get to Earth in the coming years," Busch said.

Busch's team will use the Karl G. Jansky Very Large Array (VLA) and the Very Long Baseline Array (VLBA) antennas at Pie Town and Los Alamos, New Mexico, along with a solar system radar on NASA's 230-foot antenna at Goldstone, California. The Goldstone antenna will transmit a powerful beam of radio waves toward the asteroid, and NRAO's New Mexico antennas will receive the waves reflected from the asteroid's surface.

Because of the asteroid's uneven surface and the different reflectivity of portions of the surface, the reflected radar signal will have a characteristic signature, or "speckles," as observed from Earth.

By measuring which antenna in a widely-separated pair receives the speckle pattern first, the astronomers can learn which way the asteroid is spinning. This way of using the telescopes is significantly different than their normal astronomical observing, and the research team has developed special techniques for processing the data.

How does this tell anything about the asteroid's orbital changes? Just as the afternoon is the warmest part of the day on Earth, the space rock develops a warm region that radiates infrared light in its maximum amount during "afternoon" on the asteroid. That outgoing infrared radiation provides a gentle but firm jet-like push to the asteroid. The direction of the asteroid's spin determines whether "afternoon" is either forward or rearward of its direction of motion.

If the hot spot is forward of the direction of motion, the infrared push will slow the asteroid's orbital speed, and if the hot spot is rearward of the direction of motion, it will speed up the orbital motion. This effect, over time, can make a significant change in the orbit. This is called the Yarkovsky Effect, after the engineer who first identified it.

"When the asteroid passes close to the Earth or another large body, its orbit can be changed quickly by the gravitational effect of the larger body, but the Yarkovsky Effect, though smaller, is at work all the time," Busch said.

The Goldstone-VLA-VLBA observations will be made on Feb. 16, when the asteroid's south-to-north motion in the sky makes it readily visible to those antennas.

.


Related Links
National Radio Astronomy Observatory
Asteroid and Comet Mission News, Science and Technology






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








IRON AND ICE
No asteroid risk in foreseeable future
Pasadena, Calif. (UPI) Feb 12, 2013
Despite the approach of an asteroid set to make a close flyby of Earth this week, an actual impact is unlikely for the foreseeable future, astronomers say. Although asteroid 2012 DA14 will fly past closer than some orbiting satellites, NASA says an analysis of its path shows no impact is possible. Meanwhile, U.S. astronomers have played down a report by the Voice of Russia quotin ... read more


IRON AND ICE
Building a lunar base with 3D printing

US, Europe team up for moon fly-by

Russia to Launch Lunar Mission in 2015

US, Europe team up for moon fly-by

IRON AND ICE
Rover Walkabout Continues at Cape York

Mars Rock Takes Unusual Form

In milestone, Mars rover collects first bedrock sample

How The World's Saltiest Pond Gets Its Salt; Implications For Water On Mars

IRON AND ICE
Orion Lands Safely on Two of Three Parachutes in Test

Supersonic skydiver even faster than thought

Ahmadinejad says ready to be Iran's first spaceman

Iran's Bio-Capsule Comes Back from Space

IRON AND ICE
Welcome Aboard Shenzhou 10

Reshuffle for Tiangong

China to launch 20 spacecrafts in 2013

Mr Xi in Space

IRON AND ICE
Low-Gravity Flights Will Aid ISS Fluids and Combustion Experiments

Progress docks with ISS

NASA to Send Inflatable Pod to International Space Station

ISS to get inflatable module

IRON AND ICE
Another Sea Launch Failure

ILS Concludes Yamal 402 Proton Launch Investigation

Ariane 5 delivers record payload off back-to-back launches this week

Eutelsat and Arianespace sign new multi-year multiple launch services agreement

IRON AND ICE
Earth-like planets are right next door

Direct Infrared Image Of An Arm In Disk Demonstrates Transition To Planet Formation

Kepler Data Suggest Earth-size Planets May Be Next Door

Earth-like planets may be closer than thought: study

IRON AND ICE
Researchers strain to improve electrical material and it's worth it

Explosive breakthrough in research on molecular recognition

Indra Develops The First High-Resolution Passive Radar System

ORNL scientists solve mercury mystery




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement