The Red Planet Is Mighty: First Webb Space Telescope Images

The Red Planet Is Mighty: First Webb Space Telescope Images ...

Webb's first Mars photographs, captured by its NIRCam instrument on September 5, 2022 [Guaranteed Time Observation Program 1415]. Left: NASA, ESA, CSA, STScI, and Mars JWST/GTO team demonstrating temperature differences and atmospheric disturbances.

At the Sun-Earth Lagrange point 2 (L2), Webb's unique observation point is about a million miles away from Earth. This gives a better understanding of short-term phenomena like dust storms, weather patterns, seasonal variations, and, in a single observation, processes that occur at different times of a Martian day.

The Red Planet is one of the most visible objects in the night sky because it was created to detect the very faint light from the most distant galaxies in the universe. This condition poses special challenges to Webb's observatories, because it was designed to detect such low light using extremely short exposures. Data analysis techniques

Webb is located near the second Sun-Earth Lagrange point (L2), which is approximately 1.5 million kilometers (1 million miles) from Earth on the far side of Earth from the Sun. In this orbit, Webb can maintain a safe distance from the Sun, Earth, and Moon while maintaining its position relative to Earth.

The first close-up photographs of Mars taken by Webb's Near-Infrared Camera (NIRCam) show a region of the planet's eastern hemisphere at two different wavelengths, or colors of infrared light, on the left. The two Webb NIRCam instrument field of views are shown on the right.

The NIRCam shorter-wavelength (2.1 microns) image [top right] is dominated by reflected sunlight, and thus displays surface details similar to those seen in visible-light images [left]. The Huygens Crater, the dark volcanic rock of Syrtis Major, and the Hellas Basin's brightening are all visible in this image.

The longer-wavelength (4.3 microns) image [lower right] shows thermal emission – light given off by the planet as it loses heat. The brightness of 4.3-micron light is related to the surface temperature and the atmosphere. The brightest area on the planet is where the Sun is nearly overhead, because it is generally warmer.

The James Webb Space Telescope. NASA's Goddard Space Flight Center

Because of this effect, the Hellas Basin, Mars' largest well-preserved impact structure, appears darker than its surroundings.

“This isn't a thermal effect at Hellas,” explained the principal investigator at NASA's Goddard Space Flight Center, who conducted the Webb observations. “This higher pressure results in a reduction in thermal emission at this particular wavelength range [4.1-4.4 microns] due to a pressure broadening.”

Villanueva and his colleagues also published Webb's first near-infrared spectrum of Mars, demonstrating Webb's ability to study the Red Planet using spectroscopy.

The first near-infrared spectrum of Mars captured by the Near-Infrared Spectrograph (NIRSpec) on September 5, 2022, is comprised of three slit gratings (G140H, G235H, G395H) and thermal emission at longer wavelengths. Other findings include information about dust, clouds, and surface features.

The images show subtle variations in brightness between hundreds of different wavelengths representative of the planet as a whole. Astronomers will examine the features of the spectrum to learn more about the planet's surface and atmosphere.

The researchers have been able to obtain the infrared spectrum by combining measurements from all six high-resolution spectroscopy modes of Webb's Near-Infrared Spectrograph (NIRSpec). They have written a paper to submit to a scientific journal for peer review and publication.

The Mars team will be using this imaging and spectroscopic data to investigate regional differences across the planet and to search for trace gases in the atmosphere, including methane and hydrogen chloride in the future.

Heidi Hammel of AURA conducted these NIRCam and NIRSpec observations of Mars as part of Webb's Cycle 1 Guaranteed Time Observation (GTO) solar system research.

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