JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Image

First Resolved Image of a Long-Period Comet's Nucleus

Oct 20, 2014
These images were taken of comet C/2013 A1 Siding Spring by NASA's Mars Reconnaissance Orbiter on Oct. 19, 2014, during the comet's close flyby of Mars and the spacecraft.

These images were taken of comet C/2013 A1 Siding Spring by NASA's Mars Reconnaissance Orbiter on Oct. 19, 2014, during the comet's close flyby of Mars and the spacecraft. Comet Siding Spring is on its first trip this close to the sun from the Oort Cloud at the outer fringe of the solar system. This is the first resolved imaging of the nucleus of a long-period comet.

The High Resolution Imaging Science Experiment (HiRISE) camera on Mars Reconnaissance Orbiter acquired images of this comet from a minimum distance of about 86,000 miles (138,000 kilometers), yielding a scale of about 150 yards (138 meters) per pixel. Telescopic observers had modeled the size of the nucleus as about half a mile, or one kilometer, wide. However, the best HiRISE images show only two to three pixels across the brightest feature, probably the nucleus, suggesting a size less than half that estimate.

This composite image shows two versions of each of two of the best HiRISE images of the comet. Shown at top are images with the full dynamic range, showing the nucleus and bright coma near the nucleus. Shown at bottom are versions where the fainter outer coma is brightened, saturating the inner region. The images at left and right were taken about nine minutes apart.

These closest-approach images were made possible due to very precise pointing and slewing of the Mars Reconnaissance Orbiter by engineers at Lockheed Martin in Denver, based on comet position calculations by engineers at NASA's Jet Propulsion Laboratory, Pasadena, California. HiRISE acquired three images 12 days before closest approach, when the comet was barely detectable above the "noise level" of the images. These early images indicated the comet was not quite at its predicted location. This new viewing angle on the comet was used to update its predicted location and timing at closest approach. Without this update, the comet may have been outside the HiRISE image area in the best images.

For more information on these images and future updates, see http://hirise.lpl.arizona.edu.

HiRISE is one of six instruments on NASA's Mars Reconnaissance Orbiter. The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Download JPG
Download TIFF
Mission
  • Mars Reconnaissance Orbiter
Target
  • Mars
Spacecraft
  • Mars Reconnaissance Orbiter (MRO)
Instrument
  • High Resolution Imaging Science Experiment (HiRISE)
Credit
NASA/JPL-Caltech/University of Arizona

Keep Exploring

Close-Up of Perseverance Parachute on the Martian Surface

Close-Up of Perseverance Descent Stage on the Martian Surface

Perseverance and Mars 2020 Spacecraft Components on the Surface

Perseverance's Landing Spot in Jezero Crater

Close-Up of Perseverance on the Martian Surface

Close-Up of Perseverance Heat Shield on the Martian Surface

HiRISE Captured Perseverance During Descent to Mars

Spring Sprouts on Mars

Changes of a Happy Crater

Fractured Blocks on a Crater Floor

Related Topic

News .

Testing Proves Its Worth With Successful Mars Parachute Deployment

Topic .

Mars

News .

NASA’s Perseverance Rover Gives High-Definition Panoramic View of Landing Site

News .

NASA to Reveal New Video, Images From Mars Perseverance Rover

News .

NASA's Mars Perseverance Rover Provides Front-Row Seat to Landing, First Audio Recording of Red Planet

News .

NASA’s Perseverance Rover Sends Sneak Peek of Mars Landing

News .

NASA’s Mars Helicopter Reports In

Mission .

Perseverance Rover

News .

Touchdown! NASA’s Mars Perseverance Rover Safely Lands on Red Planet

Video .

NASA's Perseverance Rover Lands Successfully on Mars (Highlight Reel)

About JPL
Who We Are
Executive Council
Directors of JPL
JPL History
Documentary Series
Virtual Tour
Annual Reports
Missions
All
Current
Past
Future
News
All
Earth
Mars
Solar System
Universe
Technology
Galleries
Images
Videos
Audio
Podcasts
Infographics
Engage
JPL and the Community
Lecture Series
Public Tours
Events
Team Competitions
JPL Speakers Bureau
Topics
Solar System
Mars
Earth
Climate Change
Stars and Galaxies
Exoplanets
Technology
JPL Life
For Media
Contacts and Information
Press Kits
More
Asteroid Watch
Robotics at JPL
Subscribe to Newsletter
Universe 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 Manager: Veronica McGregor
Site Editors: Tony Greicius, Randal Jackson, Naomi Hartono