Jupiter, center, and its moon Europa, left, are seen through the 2.12-micron filter of the NIRCam instrument on the James Webb Space Telescope. Credits: NASA, ESA, CSA and B. Holler and J. Stansberry (STScI)
Following the recent release of the first images from NASA’s James Webb Space Telescope, data from the telescope’s commissioning period is now being published in the Telescope Science Institute’s Mikulski Archive for Space Telescopes Spatial The data includes images of Jupiter and images and spectra of several asteroids. They were captured to test the telescope’s instruments before science operations officially began on July 12. Webb’s ability to track Solar System targets and produce images and spectra with unprecedented detail is demonstrated in the data.
Jupiter fans will recognize some familiar features of our solar system’s giant planet in these images seen through Webb’s infrared gaze. A view from the NIRCam instrument’s short-wavelength filter shows distinct bands surrounding the planet as well as the Great Red Spot, a storm large enough to swallow Earth. Because of the way Webb’s infrared image was processed, the iconic spot appears white in this image.
Left: Jupiter, center, and its moons Europa, Thebes, and Metis seen through the 2.12-micron filter of the NIRCam instrument on the James Webb Space Telescope. Right: Jupiter and Europa, Thebes and Metis seen through NIRCam’s 3.23 micron filter. Credits: NASA, ESA, CSA and B. Holler and J. Stansberry (STScI)
“Combined with the deep-field images released the other day, these images of Jupiter demonstrate the full understanding of what Webb can observe, from the faintest and most distant observable galaxies to the planets in our own cosmic backyard that you can see with the naked eye naked from your real backyard,” said Bryan Holler. He is a scientist at the Space Telescope Science Institute in Baltimore, who helped plan these observations.
Europa is clearly visible to the left, a moon with a probable ocean beneath its thick icy crust. It’s the goal of NASA’s upcoming Europa Clipper mission. Also, Europa’s shadow can be seen to the left of the Great Red Spot. Other Jovian moons visible in these images include Thebes and Metis.
“I couldn’t believe we could see everything so clearly and how bright they were,” said Stefanie Milam, Webb’s associate project scientist for planetary science based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s really exciting to think about the ability and the opportunity we have to observe these types of objects in our solar system.”
Jupiter and some of its moons are seen through NIRCam’s 3.23 micron filter. Credits: NASA, ESA, CSA and B. Holler and J. Stansberry (STScI)
Scientists were especially excited to see these images because they are proof that Webb can observe satellites and rings near bright objects in the solar system such as Jupiter, Saturn and Mars. Researchers will use Webb to explore the tantalizing question of whether we can see plumes of material escaping from moons like Europa and Saturn’s moon Enceladus. Webb can even see the signatures of plumes depositing material on Europa’s surface. “I think this is just one of the most exciting things we’ll be able to do with this telescope in the solar system,” Milam said.
In addition, Webb easily captured some of Jupiter’s rings, which are particularly prominent in the NIRcam long-wavelength filter image. That the rings appeared in one of Webb’s first images of the solar system is “absolutely mind-blowing and amazing,” Milam said.
“The images of Jupiter in the narrowband filters were designed to provide nice images of the entire disk of the planet, but the wealth of additional information about very faint objects (Metis, Thebes, the main ring, nebulae) in these images with approximately The one-minute exposures were absolutely a very pleasant surprise,” said John Stansberry, observatory scientist and NIRCam mission lead at the Space Telescope Science Institute.
Jupiter and its moon Europa are seen in this animation made from three images taken through the 2.12 micron filter of the NIRCam instrument. Click on the image to play the gif again. Credits: NASA, ESA, CSA and B. Holler and J. Stansberry (STScI)
Webb also obtained these images of Jupiter and Europa moving across the telescope’s field of view in three separate observations. This test demonstrated the observatory’s ability to find and track guide stars in the vicinity of bright Jupiter.
Asteroid 6481 Tenzing, center, is seen moving against a background of stars in this series of images taken by NIRCam. Click on the image to play the gif again. Credits: NASA, ESA, CSA and B. Holler and J. Stansberry (STScI)
But how fast can an object move and still be tracked by Webb? This was an important question for scientists studying asteroids and comets. During the launch, Webb used an asteroid named 6481 Tenzing, located in the asteroid belt between Mars and Jupiter, to begin the moving target tracking “speed limit” tests.
Webb was designed with the requirement to track objects moving as fast as Mars, which has a top speed of 30 milliarcseconds per second. During the launch, Webb’s team made observations of several asteroids, all of which appeared as dots because they were small. The team showed that Webb will still get valuable data with all the science instruments for objects moving up to 67 milliseconds of arc per second, which is more than twice the expected baseline, similar to photographing a turtle crawling when you’re a mile away. “Everything worked out brilliantly,” Milam said.