This Large Planet Might Have Survived the Demise of Its Star. The James Webb Space Telescope Simply Discovered Its Ambiance

New observations of WD 1856 b, a gasoline big intently orbiting a white dwarf, provide a preview of what may occur to Jupiter and Saturn after the solar dies in about 5 billion years.

Eli Stark-Elster

| AAAS Mass Media Fellow

July 7, 2026 3:09 p.m.

When astronomers found the planet WD 1856 b in 2020, the gasoline big appeared to defy their expectations of what occurs to things orbiting a useless star. The Jupiter-sized planet circles a white dwarf—the burned-out core of a useless star—in an orbit 50 instances nearer than the orbit of the Earth across the solar. Billions of years in the past, the long-dead star swelled right into a purple big and engulfed close by objects. By all rights, WD 1856 b ought to have been destroyed.

Using the James Webb Space Telescope, researchers measured the mass and temperature of WD 1856 b because it handed in entrance of its star. Shockingly, they detected an environment on the planet. This is the primary time scientists have noticed one on a planet transiting a useless star. The findings, revealed July 1 within the journal Nature, counsel the planet is oddly heat and should have moved to its present place properly after the demise of its star.

“This is one of the most bizarre planetary systems we know of,” examine co-author Christopher O’Connor, an astrophysicist at Northwestern University, tells CNN’s Ashley Strickland.

What Is the James Webb Space Telescope?

Around 80 light-years from Earth, WD 1856 b circles its gloomy host star as soon as each 34 hours at a distance of lower than two million miles. And in a putting flip of the usual celestial hierarchy, the planet is seven instances bigger than the roughly Earth-sized white dwarf it circles. 

Even for the JWST, observing WD 1856 b was a troublesome process. White dwarfs are a lot dimmer than the celebs astronomers usually examine, and the planet is simply detectable when it crosses in entrance of the dim star for a mere eight minutes. As examine co-author Victoria Boehm, an astronomer at Cornell University, places it in a statement, “If you blink you miss it.”

Fortunately, the telescope didn’t blink. By inspecting the planet throughout its stellar transits, the staff decided that WD 1856 b is between 4 and 11 instances the mass of Jupiter, and that its ambiance accommodates aerosols and natural compounds, probably together with methane. Especially stunning was the planet’s temperature: roughly 260 levels Fahrenheit, about 240 levels hotter than the faint gentle of the white dwarf may account for. 

That extra warmth grew to become the most effective clue for understanding the planet’s curious historical past. Researchers had two theories as to how WD 1856 b reached its remarkably tight orbit: the planet was engulfed by the star, or gravitational bumps from different close by objects dragged it inward properly after the hazard had already handed. To O’Connor, a wierd object sitting the place it “shouldn’t be” felt like “an invitation from the universe to get creative,” as he tells CNN.

By combining the brand new measurements with present fashions of how giant planets cool over time, the staff tracked the planet’s thermal clock. Their information counsel WD 1856 b heated up round one billion years in the past, lengthy after its host star had died. This favors the gravitational migration state of affairs—it’s also supported by the plentiful methane on the planet, which might have been diluted if the planet had been engulfed by its star. 

Still, some astronomers are skeptical of this neat account. Caroline Morley, an astronomer on the University of Texas at Austin who was not concerned within the examine, co-authored earlier analysis that instructed the planet was a lot cooler. “There are reasons to be skeptical about the result that the planet was “reheated,’” she tells CNN, although she notes that the information on its atmospheric contents are believable. Ian Crossfield, an astronomer on the University of Kansas who helped uncover WD 1856 b however didn’t take part within the new analysis, calls the conclusions about migration “provocative” and says extra examine is probably going wanted, per CNN.

The staff is already probing the ambiance of WD 1856 b in additional element by observing 4 extra transits with the JWST. This planetary system might provide a glimpse of Earth’s far-off future. In about 5 billion years, the solar will balloon right into a purple big, destroying Mercury, Venus, and probably Earth earlier than collapsing right into a white dwarf. But it now appears that the outer gasoline giants might keep on.

“Jupiter has a long life ahead of it,” lead creator Ryan MacDonald, an astrophysicist on the University of St. Andrews in Scotland, tells Scientific American‘s Sam Macdonald. As he says in an announcement: “Our results show that stellar death is not the end.”