Astronomers using the James Webb Space Telescope have peered into the atmosphere of a Jupiter-sized planet orbiting a dead white dwarf star, providing what researchers call a preview of our own solar system's distant future. The findings were published Monday by a team led by Dr. Ryan MacDonald of the University of Michigan.
A planet that survived its star's death
The exoplanet, designated WD 1856b, was discovered in 2020 using NASA's TESS and Spitzer telescopes. Located 80 light-years away in the constellation Draco, the planet orbits WD 1856+534, a white dwarf about 10 billion years old. Remarkably, the gas giant circles its star at a distance 50 times closer than Earth is from the Sun, having somehow survived the violent red giant phase that would have engulfed inner planets.
What the atmosphere reveals
Webb's spectroscopic analysis detected aerosols and hydrocarbons in the planet's atmosphere, along with chemical signatures that shed light on how a giant planet could endure its host star's death throes and migrate inward. The planet is about the size of Jupiter, while the white dwarf is Earth-sized, making the planet seven times larger than its star.
Solar system forecast
The findings serve as a natural laboratory for understanding what will happen to Jupiter and Saturn when the Sun exhausts its nuclear fuel in roughly 5 billion years. The survival and close orbit of WD 1856b suggest that gas giants can outlive their stars and end up in tight orbits around the stellar remnants, offering clues about planetary system evolution over astronomical timescales.