NASA’s James Webb Space Telescope has captured its first image of Neptune. It’s the sharpest image of this planet’s rings in more than 30 years, and it depicts this icy gas planet in a whole new light.
What is most striking about the new Webb image is how sharply it shows the planet’s rings, some of which had not been seen since NASA’s Voyager 2 became the first spacecraft to observe Earth. Neptune during its 1989 flyby. In addition to several bright, narrow rings, the Webb image clearly shows Neptune’s fainter dust lanes.
“It’s been three decades since we last saw these faint, dusty rings, and this is the first time we’ve seen them in the infrared,” says Heidi Hammel, Neptune system expert and Webb interdisciplinary scientist. The extremely stable and precise image quality of the Webb makes it possible to detect these very faint rings around Neptune.
Neptune has fascinated researchers since its discovery in 1846. Located 30 times farther from the Sun than Earth, Neptune orbits in the remote and dark region of the outer solar system. At such a distance, the Sun appears so small and dim that noon on Neptune is similar to a gloomy twilight on Earth.
This planet is characterized as an ice giant due to the chemical composition of its interior. Compared to the gas giants, Jupiter and Saturn, Neptune is much richer in elements heavier than hydrogen and helium. This is evidenced by the characteristic blue appearance of Neptune seen in Hubble Space Telescope images at visible wavelengths and is caused by small amounts of gaseous methane.
A thin line of brightness encircling the planet’s equator could be visual evidence of the global atmospheric circulation that drives Neptune’s winds and storms. The atmosphere sinks and heats up at the equator and therefore shines brighter in infrared wavelengths than the cooler gases around it.
Neptune’s 164-year orbit means its north pole (at the top of this image) is out of sight for astronomers, but the Webb images hint at an intriguing glow in that area. A previously known vortex at the south pole is evident in Webb’s view that has revealed a continuous band of high-latitude clouds surrounding it.
Covered in an icy sheen of condensed nitrogen, Triton reflects an average of 70 percent of the sunlight that hits it. It far outshines Neptune in this image because the planet’s atmosphere is obscured by methane absorption in near-infrared wavelengths. Triton orbits Neptune in a retrograde orbit, leading astronomers to suspect that this moon was originally a Kuiper belt object gravitationally captured by Neptune. More studies of Triton and Neptune with the James Webb Space Telescope are planned for next year.
The James Webb Space Telescope is the world’s premier space science observatory. The Webb will solve mysteries in our solar system, study exoplanets, and explore the mysterious structures and origins of our universe and our place in it. The Webb is an international program led by NASA with its partners, the ESA (European Space Agency) and the Canadian Space Agency.
Original news (in English)
Edition: R. Castro.