A huge planet about the size of Jupiter has been spotted orbiting a tiny white dwarf star 80 light-years away. The discovery by an international team of astronomers is puzzling because the planet should have been swallowed-up long ago, when the star expanded to become a red giant before contracting to a white dwarf.
This is the first planet known to orbit a white dwarf and its existence suggests that at least some of the Sun’s planets could survive when our star becomes a red giant in five billion years.
The white dwarf (called WD 1856+534) and the giant planet (WD 1856b) were studied using NASA’s Transiting Exoplanet Survey Satellite – which looks for fluctuations in starlight that occur when a planet passes in front of its star. TESS spotted the planet whizzing around the star once every 34 h in an extremely tight orbit that is about twenty times closer to its star than Mercury is to the Sun. Another extraordinary thing about this system is that the white dwarf is about the size of Earth, so the planet is much larger in size than the star it orbits.
No signs of destruction
“We were using the ...