The James Webb Space Telescope has returned to Earth the first high-sensitivity infrared images of Mars. They were taken on September 5, when the space observatory was at a distance of about 1.6 million km from the Red Planet.
Images of the visible part of Mars, which at the time of shooting was facing the telescope, were obtained using the NIRCam near-infrared camera. These images should provide planetary scientists with important data about Earth’s close neighbor that can be used in conjunction with information from rovers and orbiters studying Mars from space.
Since Mars is a relatively close and very bright object for the telescope, it is not easy to observe it with the James Webb instruments. To prevent the bright infrared light of the planet from blinding the instruments of the space observatory, the observation was carried out by creating very short exposures using specific equipment settings. This meant measuring part of the radiation that hit the telescope’s detectors and then applying special algorithms to analyze the collected data.
During the observation, “James Webb” received images and spectra with spatial resolution, which scientists need to study the phenomena occurring in the planet’s atmosphere, including dust storms and changes caused by the changing seasons. In addition, the telescope in one observation was able to capture what is happening on Mars during the day – during the day, at sunset and at night.
First images of Mars taken by the James Webb Telescope / Image Source: NASA, ESA, CSA, STScI, Mars JWST / GTO team
The first images of “James Webb” show the eastern hemisphere of the planet in two different ranges. The shorter wavelength image is dominated by reflected sunlight. It also shows details of the planet’s surface. These include, for example, the Huygens crater, a 450-kilometer impact crater, and dark volcanic rocks in the region of the Great Sirte plateau.
At longer infrared wavelengths, the telescope captures the light emitted by Mars, the brightness of which is related to the temperature of the planet itself and its atmosphere. The brightness decreases towards the polar regions, where there is less sunlight, as well as towards the northern hemisphere, where winter is now in full swing. The data collected by the telescope can provide clues not only about the temperature of the planet, but also the chemical composition of the atmosphere and the surface of Mars.
NIRSpec spectrograph results / Image source: NASA, ESA, CSA, STScI, Mars JWST / GTO team
The new images also demonstrate James Webb’s ability to study Mars using spectroscopy, using the observatory’s NIRSpec near-infrared spectrograph. Because chemical elements absorb and emit light at very specific wavelengths, scientists can use spectroscopy to study the so-called “fingerprints” left by chemicals in light passing through a planet’s atmosphere to determine its composition. With the help of spectroscopy, data have already been obtained on Martian dust, ice clouds, the composition of the atmosphere and the type of rocks on the surface of the planet.
It is expected that further observation of Mars using the James Webb telescope will determine the presence of water, carbon dioxide and other chemical compounds on the surface and in the atmosphere of the Red Planet. Currently, the team of scientists working within the framework of this project is preparing a report on the results of the observations made for further expert evaluation of the collected data.
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