09/19/2022
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The James Webb Space Telescope captured its first images and spectra of Mars on September 5, 2022. The telescope, an international collaboration between NASA, ESA and the Canadian Space Agency, provides a unique perspective with its infrared sensitivity on our neighboring planet, complementing the data collected by orbiters, rovers and other telescopes.
Webb’s unique observation post, almost 1.5 million kilometers away at the Sun-Earth Lagrange Point 2 (L2), offers a view of the observable disk of Mars (the part of the sunlit side facing towards the telescope). As a result, Webb is able to capture images and spectra with the spectral resolution needed to study short-term phenomena such as dust storms, weather patterns, seasonal changes, and, in a single observation, processes that occur at different times (during the day, sunset, of sun and night). night) of a Martian day.
Because it is so close, the Red Planet is one of the brightest objects in the night sky in terms of visible light (that human eyes can see) and the infrared light that Webb is designed to detect. This poses special challenges for the observatory, which was built to detect the extremely faint light from the most distant galaxies in the universe. Webb’s instruments are so sensitive that, without special observing techniques, the bright infrared light from Mars is blinding, causing a phenomenon known as “detector saturation.” Astronomers adjusted for the extreme brightness of Mars using very short exposures, measuring only part of the light reaching the detectors, and applying special data analysis techniques.
Webb’s first images of Mars, captured by the near-infrared camera (NIRCam), show a region of the planet’s eastern hemisphere in two different wavelengths, or colors, of infrared light. This image shows a NASA surface reference map and the Mars Orbiter Laser Altimeter (MOLA) on the left, with the two fields of view from the Webb NIRCam instrument superimposed. Near-infrared images of Webb are shown to the right.
Webb’s first near-infrared spectrum of Mars, captured by the near infrared spectrograph (NIRSpec), demonstrates Webb’s power to study the Red Planet with spectroscopy.
While images of Mars show built-in differences in brightness over a large number of wavelengths from place to place across the planet on a particular day and time, the spectrum shows the subtle variations in brightness between hundreds of different wavelengths. wavelengths representative of the planet as a whole. Astronomers will analyze the features of the spectrum to gather additional information about the planet’s surface and atmosphere.
In the future, Webb will use these spectroscopic and imaging data to explore regional differences across the planet and look for trace species in the atmosphere, including methane and hydrogen chloride.
These observations of Mars were made as part of Webb Cycle 1 Guaranteed Time Observation (GTO) Solar System Program led by Heidi Hammel of the Association of Universities for Research in Astronomy (AURA).
ESA operates two Mars orbiters, Mars Express and the exorcise you Trace Gas Orbiter, which has brought back a treasure trove of information about the Red Planet’s atmosphere and surface. In addition, ESA is collaborating with the Japan Aerospace Exploration Agency (JAXA) on the soon-to-be-launched Martian Moons eXploration (MMX) mission to Mars’ moon Phobos.
NIRSpec it was built for the European Space Agency (ESA) by a consortium of European companies led by Airbus Defense and Space (ADS) with NASA’s Goddard Space Flight Center providing its detector and micro-shutter subsystems.
Note: This post highlights images of Webb science in progress, which has not yet gone through the peer review process.
