Updated

Updated · Nature.com · Jul 1

JWST Detects Hydrocarbons on WD 1856 b, Pins White Dwarf Planet at 4.3–10.9 Jupiter Masses

Updated

Updated · Nature.com · Jul 1

JWST Detects Hydrocarbons on WD 1856 b, Pins White Dwarf Planet at 4.3–10.9 Jupiter Masses

Q: If Jupiter realigns after our Sun dies, could it become a new heat source for the frozen inner planets like Earth?

No. Even if Jupiter were to migrate inward after the Sun becomes a white dwarf, it would not become a meaningful new heat source for Earth or the other inner planets. The new JWST study of WD 1856 b shows what can happen to a Jupiter-like world after its star dies. That planet moved inward long after the red giant phase and was reheated by tidal forces, leaving it much warmer than the white dwarf’s light alone can explain. But that heat is internal to the planet and gradually fading. It does not turn the planet into a star, and it would not radiate enough energy to warm distant rocky planets in any significant way. There is also a more basic problem: the inner Solar System is unlikely to be intact by then. Mercury and Venus are expected to be engulfed when the Sun swells into a red giant. Earth may also be destroyed, though some models suggest it could survive in a wider orbit around the future white dwarf Sun. In either case, any surviving Earth would be cold and far away, and Jupiter’s residual heat would be negligible at that distance. Jupiter cannot ignite fusion, so it cannot become a replacement Sun. At most, the WD 1856 b result suggests that gas giants can survive stellar death, migrate later, and stay unusually warm for billions of years. That is important for understanding the Solar System’s far future, but not as a realistic way to reheat frozen inner planets.

3 articles · Updated · Nature.com · Jul 1

JWST transmission spectra of WD 1856 b revealed hydrocarbons, aerosols and nightside thermal emission, marking an atmospheric detection for a planet orbiting a white dwarf.
The 0.5–5.0 micron data point to a carbon-rich atmosphere with about 7% methane and an effective temperature of 390–412 K, far above the planet’s roughly 160 K equilibrium temperature.
That spectrum also let researchers constrain WD 1856 b’s mass to 4.3–10.9 Jupiter masses, resolving a key uncertainty about the Jupiter-sized planet on a 1.4-day, 0.02-au orbit.
Cooling models indicate the planet was reheated 3.0–5.5 billion years into the white dwarf phase, making common-envelope survival unlikely and favoring later high-eccentricity migration followed by tidal circularization.
The result gives astronomers their clearest look yet at how giant planets can survive a star’s death and evolve around white dwarfs—offering a possible preview of the Solar System’s distant future.

Sources

Nature.com23h ago

JWST Detects Hydrocarbons, Aerosols in White Dwarf Planet WD 1856 b's Atmosphere, Constrains Mass

European Space Agency23h ago

Webb Telescope Reveals How Exoplanet WD 1856 b Survived Star's Death, Reached Tight Orbit

ScienceAlert8h ago

JWST Reveals Hotter-Than-Expected Atmosphere of Exoplanet WD 1856b Orbiting White Dwarf

6 Sources

How did a gas giant seven times larger than its star survive stellar death to orbit it in just 34 hours?

Methane was detected on a planet orbiting a dead star. What does this mean for the chemistry of post-apocalyptic planetary systems?

If Jupiter realigns after our Sun dies, could it become a new heat source for the frozen inner planets like Earth?

WD 1856 b and the Fate of Planets: Unveiling the First Close-Orbit Gas Giant Around a White Dwarf

Overview

The discovery of WD 1856 b, a Jupiter-sized planet orbiting an Earth-sized white dwarf, has amazed astronomers and changed our view of planetary survival after stellar death. Using NASA’s James Webb Space Telescope, scientists confirmed this planet’s existence and began to solve the mystery of how it survived its star’s red giant phase. WD 1856 b orbits extremely close to its white dwarf host, which is the leftover core of a Sun-like star that expanded billions of years ago. This finding gives new insight into the future of solar systems and shows that planets can endure even after dramatic changes in their stars.

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