James Webb Telescope captures its first images of an exoplanet

Exoplanets are rarely seen in images.
Stephen Vicinanza
Webb takes its first exoplanet image.
Webb takes its first exoplanet image.

ESA 

In a first for the James Webb Telescope, astronomers from the joint NASA/ESA/CSA cooperative used the space-based telescope to bring back images of an exoplanet. Exoplanets are planets orbiting other suns than our own, helping us to understand if we are unique in the universe or if other Earth-like planets exist.

The images of the exoplanet are seen through four different light filters. They show a gas giant, a planet with no rocky surface that could not be habitable. The light filters show how the infrared telescope's gaze is easily capturing images of planets out beyond our solar system. These images lead the way toward future observations that can reveal a broad range of information never before seen on exoplanets.

Named HIP 65426 b is a gas giant about six to eight times the size of Jupiter, which is an enormous planet indeed. It is only about 15 to 20 million years old, which in planet years is very young. Our own Earth is about four to five billion years old.

In 2017 astronomers from Chile, using the SPHERE instrument on the European Southern Observatory's Very Large Telescope (VLT), took images of the HIP 65426 b using short infrared wavelengths of light. The image today is taken in mid-infrared light. It reveals much more detail than the ground-based telescopes at the VLT campus. This is due to the intrinsic infrared glow of the Earth's atmosphere.

Researchers from the NASA/ESA/CSA cooperative are preparing a paper of their observations, which will be submitted to journals for peer review. The fact that these detailed images captured an exoplanet so well is already leading to future possibilities for studying distant worlds.

One of the concerns researchers had was making certain there was a star associated with the large gas giant, proving it was indeed an exoplanet and not a dwarf star. The images from the Webb telescope show HIP 65426 b is sufficiently close to a star to be in its orbit and is about 100 times further from that star than Earth is from our own star. The distance from HIP 65426 b to its sun is also sufficient to distinctly separate the two in the image.

The difficulty in getting images of exoplanets is stars are so much brighter than planets. The HIP 65426 b planet is more than 10,000 times fainter than its host star in the near-infrared, possibly 3,000 times fainter in the mid-infrared. The images of exoplanets taken from space are not unique to the Webb telescope. The Hubble Space Telescope has captured exoplanet images. The images of HIP 65426 b are leading the way to Webb's exploration of exoplanets.

In each of the filtered infrared images, the exoplanet appears as a blob of light. This is a particular way the James Webb Telescope optical systems translate light through the different optical formats. The purple shows the NIRCam instruments view at 3.00 micrometers, and the blue shows the NIRCam instruments view at 4.44 micrometers. The yellow images show the mid-infrared instrument's view at 11.4 micrometers, and the red shows the mid-infrared instrument's view at 15.5 micrometers. The Webb instrument captures light differently, and so the images have different presentations. The star in each image denotes to host star's position in relation to the exoplanet. In the NIRCam images, the bar shapes are artifacts (optic interference) and not objects surrounding the exoplanet.

The image set observations were led with an enormous collaboration by Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter in the United Kingdom.

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