JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Asteroids and Comets
.

Arecibo Radar Returns with Asteroid Phaethon Images

Dec. 22, 2017
These radar images of near-Earth asteroid 3200 Phaethon were generated by astronomers at the National Science Foundation's Arecibo Observatory on Dec. 17, 2017. Observations of Phaethon were conducted at Arecibo from Dec.15 through 19, 2017. At time of closest approach on Dec. 16 at 3 p.m. PST (6 p.m. EST, 11 p.m. UTC) the asteroid was about 6.4 million miles (10.3 million kilometers) away, or about 27 times the distance from Earth to the moon. The encounter is the closest the asteroid will come to Earth until 2093.› Full image and caption
Credit: Arecibo Observatory/NASA/NSF

Months after Hurricane Maria, the Arecibo Observatory Planetary Radar has resumed normal operations, providing high-resolution images of the asteroid 3200 Phaethon Earth flyby.

Updated Version as of 11 am PST: corrections include close approach distance and size comparison to asteroid Bennu.

After several months of downtime since Hurricane Maria struck the island of Puerto Rico, the Arecibo Observatory Planetary Radar has returned to normal operation, providing the highest-resolution images to date of near-Earth asteroid 3200 Phaethon during its December 2017 close approach to Earth. The radar images, which are subtle at the available resolution, reveal the asteroid is spheroidal (roughly ball-shaped) and has a large concavity, or depression, at least several hundred meters in extent near its equator, and a conspicuous dark, circular feature near one of the poles. Arecibo's radar images of Phaethon have resolutions as fine as about 250 feet (75 meters) per pixel.

"These new observations of Phaethon show it may be similar in shape to asteroid Bennu, the target of NASA's OSIRIS-REx spacecraft, but more than 1,000 Bennus could fit inside of Phaethon," said Patrick Taylor, a Universities Space Research Association (USRA), Columbia, Maryland, scientist and group leader for Planetary Radar at Arecibo Observatory. "The dark feature could be a crater or some other topographic depression that did not reflect the radar beam back to Earth."

Radar images obtained by Arecibo indicate Phaethon has a diameter of about 3.6 miles (6 kilometers) -- roughly 0.6 miles (1 kilometer) larger than previous estimates. Phaethon is the second largest near-Earth asteroid classified as "Potentially Hazardous." Near-Earth objects are classified as potentially hazardous asteroids (PHAs), based on their size and how closely they can approach Earth's orbit.

Tracking and characterizing PHAs is a primary mission of NASA's Planetary Defense Coordination Office. Radar is a powerful technique for studying asteroid sizes, shapes, rotation, surface features and roughness, and for more precise determination of their orbital path, when they pass relatively close to Earth.

"Arecibo is an important global asset, crucial for planetary defense work because of its unique capabilities," said Joan Schmelz of USRA and deputy director of Arecibo Observatory. "We have been working diligently to get it back up and running since Hurricane Maria devastated Puerto Rico."

The Arecibo Observatory has the most powerful astronomical radar system on Earth. On Sept. 20, the telescope suffered minor structural damage when Maria, the strongest hurricane to hit the island since 1928, made landfall. Some days after the storm, the observatory resumed radio astronomy observations, while also serving as a base for relief efforts to surrounding communities. Radar observations, which require high power and diesel fuel for generators at the site, resumed operations in early December after commercial power returned to the observatory and the generators could then be used exclusively for the radar.

Asteroid 3200 Phaethon was discovered on Oct. 11, 1983, by NASA's Infrared Astronomical Satellite (IRAS), and the planetary dust that produces the annual Geminid meteor shower originates from this asteroid. Observations of Phaethon were conducted at Arecibo from Dec. 15 through 19, 2017, using the NASA-funded planetary radar system. At time of closest approach on Dec. 16 at 3 p.m. PST (6 p.m. EST, 11 p.m. UTC) the asteroid was about 6.4 million miles (10.3 million kilometers) away, or about 27 times the distance from Earth to the moon. The encounter is the closest the asteroid will come to Earth until 2093, but it came a little closer in 1974 and about half this distance back in 1931 before its existence was known.

The Arecibo Planetary Radar Program is funded by NASA's Near-Earth Object Observations Program through a grant to Universities Space Research Association (USRA), from the Near-Earth Object Observations program. The Arecibo Observatory is a facility of the National Science Foundation operated under cooperative agreement by SRI International, USRA, and Universidad Metropolitana.

NASA's Planetary Defense Coordination Office is responsible for finding, tracking and characterizing potentially hazardous asteroids and comets coming near Earth, issuing warnings about possible impacts, and assisting coordination of U.S. government response planning, should there be an actual impact threat.

More information about the National Science Foundation's Arecibo Observatory can be found at:

http://www.naic.edu

More information about asteroids and near-Earth objects can be found at:

https://cneos.jpl.nasa.gov

https://www.jpl.nasa.gov/asteroidwatch

For more information about NASA's Planetary Defense Coordination Office, visit:

https://www.nasa.gov/planetarydefense

For asteroid and comet news and updates, follow AsteroidWatch on Twitter:

twitter.com/AsteroidWatch

https://www.jpl.nasa.gov/images/asteroid/20171222/PIA22185.gif
› Asteroid watch site
› Full image and caption

News Media Contact

Suraiya Farukhi

410-740-6224

sfarukhi@usra.edu

DC Agle

Jet Propulsion Laboratory, Pasadena, Calif.

818-393-9011

agle@jpl.nasa.gov

Dwayne Brown

202-358-1726

dwayne.c.brown@nasa.gov

2017-325

Related News

Climate Change .

NASA Uses 30-Year Satellite Record to Track and Project Rising Seas

Weather .

Ranking Atmospheric Rivers: New Study Finds World of Potential

Solar System .

NASA’s Magellan Data Reveals Volcanic Activity on Venus

Mars .

Engineers Keep an Eye on Fuel Supply of NASA’s Oldest Mars Orbiter

Solar System .

Study Finds Ocean Currents May Affect Rotation of Europa’s Icy Crust

Earth .

NASA and Italian Space Agency Join Forces on Air Pollution Mission

Earth .

NASA-ISRO Science Instruments Arrive in India Ahead of 2024 Launch

Climate Change .

NASA Space Mission Takes Stock of Carbon Dioxide Emissions by Countries

Earth .

Removing Traces of Life in Lab Helps NASA Scientists Study Its Origins

Solar System .

Study Finds Venus’ ‘Squishy’ Outer Shell May Be Resurfacing the Planet

Explore More

Image .

30 Years of Sea Level Rise

Image .

Chausey, French Channel Islands

Event April 20, 2023 .

Earth Surface Mineral Dust Source Investigation (EMIT) Mission

Mission .

Lunar Trailblazer

Image .

Poniente Almeriense, Spain

Image .

COWVR, TEMPEST Track Tropical Cyclone Mandous

Image .

Radar Observations of Elongated Near-Earth Asteroid 2011 AG5

Image .

Chaine des Puys, France

Image .

Three-Telescope View of the Sun

Image .

Satellites Assess Earthquake Damage in Turkey

About JPL
Who We Are
Executive Council
Directors
Careers
Internships
The JPL Story
JPL Achievements
Documentary Series
Annual Reports
Missions
Current
Past
Future
All
News
All
Earth
Solar System
Stars and Galaxies
Subscribe to JPL News
Galleries
Images
Videos
Audio
Podcasts
Apps
Visions of the Future
Slice of History
Robotics at JPL
Events
Lecture Series
Team Competitions
Speakers Bureau
Calendar
Visit
Public Tours
Virtual Tour
Directions and Maps
Topics
JPL Life
Solar System
Mars
Earth
Climate Change
Exoplanets
Stars and Galaxies
Robotics
More
Asteroid Watch
NASA's Eyes Visualizations
Universe - Internal Newsletter
Social Media
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Managers: Veronica McGregor, Randal Jackson
Site Editors: Tony Greicius, Naomi Hartono
CL#: 21-0018