NASA’s James Webb Space Telescope (JWST) has captured the first clear evidence of auroras on Neptune, marking a significant milestone in understanding the outer reaches of our solar system. The telescope revealed an aurora shimmering across Neptune’s atmosphere, providing new insights into the planet’s magnetic field and upper atmosphere.
Auroras form when high-energy particles from the Sun are trapped by Neptune’s magnetic field and collide with its upper atmosphere, producing a glowing light display. The JWST used its near-infrared sensitivity to take spectroscopic images of Neptune and analyze different light wavelengths emitted by the planet.
The research team detected a clear emission line suggesting the presence of the trihydrogen cation (H₃⁺), which can form in auroras. This detection confirms long-held expectations and provides new insights into how Neptune’s magnetic field interacts with solar particles.
The data collected by JWST has revealed that Neptune’s upper atmosphere has cooled significantly, with temperatures several hundred degrees lower than they were in 1989. The findings suggest why Neptune’s auroras had not been detected for so long: the planet’s magnetic field is tilted at an unusual 47-degree angle relative to its rotation axis.
The success of JWST in capturing this evidence opens up new possibilities for studying Neptune over a full solar cycle, which could shed light on Neptune’s erratic magnetic field and provide insights into its origin.
Source: https://www.jpost.com/science/science-around-the-world/article-849655