Mars (NIRCam Images)

Editor’s Note: The findings reported here are based on preliminary results that have not been shared formally with the scientific community via peer-reviewed publication.

The first images of Mars, captured by the Webb’s Near-Infrared Camera (NIRCam) on September 5, 2022, reveal reflective and thermal properties of the planet with sufficient sensitivity and resolution to explore localized phenomena. 

Left: A reference map of Mars from NASA and the Mars Orbiter Laser Altimeter (MOLA) shows the view from Webb, with the orientation and lighting of the planet at the day and time of the observation. The observation was made on September 5, 2022, during summer in Mars’ southern hemisphere. The central longitude is approximately 80 degrees east. The axis is tilted 25 degrees from perpendicular to the orbital plane. The eastern portion of the disc is in evening shadow. The map shows topographic features and surface coloring that are typically visible in reflected sunlight. Three features are labeled: Syrtis Major, a dark-colored volcanic region; the Huygens Crater, a complex impact crater; and the Hellas Basin, the largest preserved impact structure on Mars. 

Top right: A NIRCam image shows 2.1-micron (F212 filter) reflected sunlight, revealing surface features similar to those seen in the base map, including the dark volcanic rocks of Syrtis Major, light rings of the Huygens Crater, and a section of the Hellas Basin, which may be coated in a layer of light-colored dust. The field of view is outlined in blue on the base map. 

Bottom right: Another NIRCam image, captured simultaneously, shows ~4.3-micron (F430M filter) emitted light that reveals temperature differences with latitude and time of day, as well as darkening caused by atmospheric effects. The measured brightness is highest near the subsolar region (yellow) and decreases noticeably toward the northern hemisphere (which is experiencing winter) and toward the western hemisphere (which is in night-time darkness). However, the measured brightness of the Hellas Basin is less than its surroundings not because it has a lower temperature, but rather because it is deeper (more than 4 miles, or 7 kilometers, below the surrounding terrain) and experiences higher air pressure. This dampens the thermal emission at this wavelength: Some of the 4.3-micron light emitted from the basin is absorbed by molecules like carbon dioxide in Mars’ atmosphere.

NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center.

See the Fast Facts below for additional technical details. 

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