For the first time, astronomers have used NASA’s James Webb Space Telescope to capture a direct image of a planet outside our solar system, in what has been described as a “historic moment for astronomy”. The exoplanet chosen was HIP 65426 b, which is about six to 12 times the mass of Jupiter and between 15 and 20 million years old—a young age compared to the 4.5 billion-year-old Planet Earth. Since the planet is a gas giant, similar to Jupiter, it would never be habitable by living organisms. The image, seen through four different light filters, shows how Webb’s powerful infrared gaze can easily capture worlds beyond our solar system. “This is a transformative moment, not just for Webb but for astronomy in general,” said Sasha Hinkley, associate professor of physics and astronomy at the University of Exeter. “James Webb is going to open the door to a whole new class of planets that have been completely inaccessible to us, and by observing them at a wide range of wavelengths we can study their compositions in a much more in-depth way. An image shows the exoplanet HIP 65426 b in different bands of infrared light, as seen by the James Webb Space Telescope. / Nasa Image credit: Nasa Taking direct images of exoplanets is challenging because stars are much brighter than planets. The planet HIP 65426 b is over 10,000 times fainter than its host star in the near-infrared and a few thousand times fainter in the mid-infrared. HIP 65426 b was first discovered in 2017 by astronomers using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope. Because of Webb’s longer infrared wavelengths, its images revealed new details that ground-based telescopes would not have been able to detect due to the inherent infrared glow of Earth’s atmosphere. “Getting this image was like hunting for space treasure,” said Aarynn Carter, a postdoctoral researcher at the University of California, Santa Cruz, who led the analysis of the images. “At first, all I could see was light from the star, but with careful image processing I was able to remove that light and reveal the planet.” Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) are equipped with coronagraphs, which are sets of tiny masks that block out starlight, allowing Webb to take direct images of some exoplanets like it. While this is not the first direct image of an exoplanet taken from space – the Hubble Space Telescope has previously captured direct images of an exoplanet – it is the first images of an exoplanet using infrared light, which gives a much more accurate indication of a star’s mass. planet and temperature and will allow astronomers to detect the planet’s weather. “I think the most exciting thing is that we’re just getting started,” Carter said. “There are many more images of exoplanets to come that will shape our overall understanding of their physics, chemistry and formation. We may even discover previously unknown planets.” JWST is the largest and most powerful space science telescope ever launched, designed to give scientists a more detailed look at the beginning of the universe, the birth of stars and possibly the origin of life. After 14 years of delays, the telescope launched on an Ariane 5 rocket on Christmas Day 2021 from Europe’s spaceport in French Guiana. After launch, JWST underwent a painstaking months-long process to slowly unfold the tennis court-sized sunburst as Nasa engineers anxiously watched for damage during the launch process. JWST’s light-gathering capacity is twice that of Hubble, and its size is larger than two double-decker buses. In its eight months in space, the device has already allowed scientists to capture unprecedented images, such as those of Jupiter’s storms and what is believed to be the “deepest view of the universe” to date.
In the future, the James Webb Space Telescope is expected to make detailed observations of more distant Earth-like planets, including those with potentially habitable conditions. Subscribe to the E&T News email to get great stories like this delivered to your inbox every day.