A rare alien world that looks billions of years younger than its actual age may have been discovered around a stellar corpse known as a white dwarf by NASA’s Spitzer Space Telescope.
Astronomers suspect a rejuvenated planet, worlds that have been hypothetical until the discovery of this potential candidate – a massive Jupiter-like gas giant in orbit around the white dwarf called PG 0010+280 and of which has got old before brightening up with a radiant, youthful glow.
“When planets are young, they still glow with infrared light from their formation,” explains Michael Jura of the University of California, Los Angeles (UCLA). “But as they get older and cooler, you can’t see them anymore. Rejuvenated planets would be visible again.”
Rejuvenated planets are thought to reclaim their youth by sucking mass from their dying star. When stars like our Sun age, they burn up their fuel and swell into a red giant before puffing off their outer layers to reveal a core – the stellar skeleton dubbed a white dwarf. These dying stars blow winds of material outwards, which could be snatched by giant planets circling them.
Jura and his team of astronomers at UCLA were alerted to the possible existence of a rejuvenated world when they noticed an excess of infrared light they initially thought to be coming from a disc of material, likely to have been made by asteroids getting chewed up by the white dwarf’s gravitational forces.
However, data from Spitzer suggests that the infrared light isn’t coming from a disc made of crushed asteroids – it’s most likely coming from a small ‘failed star’ companion known as a brown dwarf or, more interestingly, from a rejuvenated planet.
“I find the most exciting part is that this infrared excess could potentially come from a giant world, though we need more work to prove it,” said Siyi Xu of UCLA and the European Southern Observatory (ESO) in Germany, who hopes that NASA’s upcoming James Webb Space Telescope (JWST) will provide a clearer picture. “If confirmed, it would directly tell us that some planets can survive the red giant stage of stars and be present around white dwarfs.”