How Does A Planet Survive The Death Of Its Star?
On 1st July 2026, new findings from the James Webb Space Telescope (Webb) were published. They shed light on the far future of planetary systems like our own. A Sun-like star that lived out its life became a red giant and then shed its outer layers, leaving a hot, dense core called a white dwarf. In theory, a red giant should engulf nearby planets, but researchers have detected a Jupiter-sized planet orbiting WD 1856+534 every 34 hours, at a distance of less than 3 million kilometers from the white dwarf. This surprising configuration raises questions about how such a planet could survive the star’s dramatic late stages.
The planet, named WD 1856 b, was first spotted in 2020 by NASA’s Transiting Exoplanet Survey Satellite (TESS) and the Spitzer Space Telescope. It orbits the white dwarf about 80 light-years away from Earth. Lead author Ryan MacDonald, of the University of St Andrews, describes the planet as roughly the size of Jupiter while its host star is about the size of Earth, making the planet far larger than its star.
WD 1856 b travels very close to its star—about 50 times nearer than Earth is to the Sun. If the planet had started there, it would likely have been destroyed when the star expanded into a red giant. So, scientists ask: how did WD 1856 b endure the star’s death and end up in its current orbit?
Webb’s observations help map a possible path for the planet’s journey. The telescope watched a transit, when the planet passes in front of the star, to gather data on the planet’s mass and temperature. The mass is estimated to fall between four and eleven times that of Jupiter. The infrared light during transit indicates a surface temperature near 126 degrees Celsius, which is higher than expected if the planet only received heat from the white dwarf. This temperature clue supports one of two scenarios for the planet’s inward movement.
Two researchers, including Christopher O’Connor of Northwestern University, explored how WD 1856 b could have moved inward. One idea is that the planet started inside the red giant’s influence and survived the engulfment. A second idea points to gravitational interactions with other objects in the system, which includes a distant companion star in a triple-star arrangement. By combining cooling models with Webb’s mass and temperature data, the team estimated when the heating occurred. They conclude the heating likely happened between 3 and 5.5 billion years after the star became a white dwarf, suggesting the planet was on a wider orbit during the red giant phase and only moved inward later.
Spectral analysis of the planet’s atmosphere through starlight revealed signatures of small cloud particles and hydrocarbons, probably methane, marking the first detected atmosphere on a planet transiting a dead star. The team plans to observe more transits to refine atmospheric chemistry.
In the wider context, this research informs possible futures for our Solar System. In about five billion years, the Sun will become a red giant and then a white dwarf, possibly threatening inner worlds. The fate of distant gas giants remains uncertain. Understanding WD 1856 b helps scientists imagine what may happen to planets around aging stars.
On 1st July 2026, new findings from the James Webb Space Telescope (Webb) were published. They shed light on the far future of planetary systems like our own. A Sun-like star that lived out its life became a red giant and then shed its outer layers, leaving a hot, dense core called a white dwarf. In theory, a red giant should engulf nearby planets, but researchers have detected a Jupiter-sized planet orbiting WD 1856+534 every 34 hours, at a distance of less than 3 million kilometers from the white dwarf. This surprising configuration raises questions about how such a planet could survive the star’s dramatic late stages.
The planet, named WD 1856 b, was first spotted in 2020 by NASA’s Transiting Exoplanet Survey Satellite (TESS) and the Spitzer Space Telescope. It orbits the white dwarf about 80 light-years away from Earth. Lead author Ryan MacDonald, of the University of St Andrews, describes the planet as roughly the size of Jupiter while its host star is about the size of Earth, making the planet far larger than its star.
WD 1856 b travels very close to its star—about 50 times nearer than Earth is to the Sun. If the planet had started there, it would likely have been destroyed when the star expanded into a red giant. So, scientists ask: how did WD 1856 b endure the star’s death and end up in its current orbit?
Webb’s observations help map a possible path for the planet’s journey. The telescope watched a transit, when the planet passes in front of the star, to gather data on the planet’s mass and temperature. The mass is estimated to fall between four and eleven times that of Jupiter. The infrared light during transit indicates a surface temperature near 126 degrees Celsius, which is higher than expected if the planet only received heat from the white dwarf. This temperature clue supports one of two scenarios for the planet’s inward movement.
Two researchers, including Christopher O’Connor of Northwestern University, explored how WD 1856 b could have moved inward. One idea is that the planet started inside the red giant’s influence and survived the engulfment. A second idea points to gravitational interactions with other objects in the system, which includes a distant companion star in a triple-star arrangement. By combining cooling models with Webb’s mass and temperature data, the team estimated when the heating occurred. They conclude the heating likely happened between 3 and 5.5 billion years after the star became a white dwarf, suggesting the planet was on a wider orbit during the red giant phase and only moved inward later.
Spectral analysis of the planet’s atmosphere through starlight revealed signatures of small cloud particles and hydrocarbons, probably methane, marking the first detected atmosphere on a planet transiting a dead star. The team plans to observe more transits to refine atmospheric chemistry.
In the wider context, this research informs possible futures for our Solar System. In about five billion years, the Sun will become a red giant and then a white dwarf, possibly threatening inner worlds. The fate of distant gas giants remains uncertain. Understanding WD 1856 b helps scientists imagine what may happen to planets around aging stars.
