Hiding in JWST’s image of Jupiter is the volcanic moon Io interacting with Jupiter’s aurora — creating a small bump in the aurora low in the planet’s sky. The image reveals “material coming from Io streaming down the magnetic field lines,” said Melin. The effect has been seen before, but it was easily picked out by JWST with barely a glance at the planet.
JWST is probing planets in other star systems too. Already, the telescope has taken a peek at the famous TRAPPIST-1 system, a red dwarf star with seven Earth-size worlds (some potentially habitable), though the data is still being analyzed. Early observations have been released of a less hospitable planet, a “hot Jupiter” called WASP-96 b, in a tight 3.4-day orbit around its star.
JWST found water vapor in the planet’s atmosphere, confirming evidence of water reported days earlier by Chima McGruder of the Harvard-Smithsonian Center and colleagues, who used a ground-based telescope. But JWST can go further; by observing WASP-96 b’s ratio of carbon to oxygen, it may be able to solve a confounding mystery about hot Jupiters: how they attain such close orbits around their stars. More oxygen would suggest that the gas giant initially formed far from the star where water could condense, while a higher carbon ratio would suggest that it’s always been close in.
Meanwhile, JWST may have spotted a temporary light in the sky — a short-lived event known as a transient — which it was not initially designed to do. The astronomer Mike Engesser and colleagues at the Space Telescope Science Institute in Baltimore, Maryland (the operations center for JWST), noticed a bright object not apparent in Hubble images of the same region. They think it’s a supernova, or exploding star, some 3 billion light-years away — proof that the telescope can find these events.
JWST should be capable of finding far more distant supernovas too, which will give it another way to serve as a probe of the early universe. It may also find stars being torn apart by the supermassive black holes that reside at galaxies’ centers, something no previous telescope has seen. “For the first time we’re going to be able to peer into these very deep, dark regions,” said Ori Fox, an astronomer at the Space Telescope Science Institute who leads the team studying transients.
Transients, like other astronomical phenomena, are set to be redefined. After decades of planning and construction, JWST has hit the sky running. The issue now is keeping pace with the constant barrage of science coming down from a machine so complex yet faultless it almost defies belief that it was built by human brains. “It’s working, and it’s insane,” said Larson.