James Webb reveals Neptune’s rings in a dazzling new light

22 Sep 2022

An image of Neptune taken by the James Webb Space Telescope's Near-Infrared Camera. Image: NASA/ESA/CSA/STScI

The latest image of our solar system’s most distant planet shows Neptune’s rings and seven of its moons, including the unusual Triton.

New images of Mars were released this week from the James Webb Space Telescope. But the powerful space observatory isn’t taking time off, as it shifts its gaze to another planet in our solar system.

James Webb has captured a striking new image of Neptune, the distant ice giant in our solar system. The image shows the planet in a unique light, with some of its moons making an appearance.

NASA said the image gives us the clearest view of Neptune’s rings in more than 30 years, since the Voyager 2’s observation back in 1989. The new image also shows the planet’s fainter dust bands.

“It has been three decades since we last saw these faint, dusty rings, and this is the first time we’ve seen them in the infrared,” said Heidi Hammel, a Neptune system expert and interdisciplinary scientist for Webb.

Neptune is characterised as an ice giant due to its interior chemical make-up. The planet is richer in heavy elements than our gas giants Jupiter and Saturn.

This also explains Neptune’s signature blue appearance in Hubble Space Telescope images, which is caused by small amounts of gaseous methane.

However, Webb’s Near-Infrared Camera (NIRCam) captures objects in a different wavelength to Hubble, so Neptune appears in a brighter colour.

The new image reveals some intriguing brightness at the planet’s northern pole. Due to Neptune’s 164-year orbit, this pole is just out of view for astronomers.

Webb also managed to capture seven of Neptune’s 14 known moons. The most striking of these is a large and unusual point of light some distance from the ice giant. What appears at first as a star is actually Neptune’s unusual moon, Triton.

An image of Neptune and some of its moons, captured by the James Webb Space Telescope. The unusual moon Triton reflects an average of 70pc of the sunlight that hits it. Image: NASA/ESA/CSA/STScI

As Triton is covered in condensed nitrogen, NASA said the moon reflects roughly 70pc of the sunlight that hits it.

The unusual moon orbits Neptune in a bizarre backward orbit, which leads astronomers to speculate that Triton was actually a Kuiper Belt object that was gravitationally captured by Neptune.

NASA and the European Space Agency said additional Webb studies of both Triton and Neptune are planned for next year.

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Leigh Mc Gowran is a journalist with Silicon Republic