Astronomers Find First-Ever Planet Orbiting Dead Star
Humanity has existed for 300,000 years, give or take a millennium. That might sound like a long time when the average human lives at most a few decades, but it’s really just a cosmic blink of the eye. Even if Homo sapiens exceeds all expectations and survives both political strife and climate change, the sun will eventually turn Earth into a cinder. However, a new discovery from the W. M. Keck Observatory in Hawaii suggests there might be some hope for at least one planet to survive the future cataclysm. Around a distant stellar corpse, astronomers have spotted a surviving gas giant planet for the first time. Could that mean Jupiter is destined to survive the sun’s death throes?
We think of Earth as a constant, but no matter what we do or don’t do, we’ve got about a billion years left here. The sun gets warmer as it ages and uses up its nuclear fuel, and eventually, it will evaporate the earth’s oceans and burn away the atmosphere. Even if life somehow survives that, in a few billion more years, the sun will expand into a red giant that consumes Earth completely. We’ve always thought that the ferocious effects of the red giant transformation would tear apart all the planets, but maybe not.
The solar system in question is near the center of our Milky Way galaxy, and we know it has at least one exoplanet. The team discovered the giant planet thanks to gravitational microlensing, which occurs when the gravity from a foreground object (like a star) magnifies a more distant one. If there’s a planet orbiting the star, as it is here, it causes detectable warping of the light as it passes by.
When the team looked at the star itself, they were surprised to find that it wasn’t bright enough to be a main-sequence star. They also found it couldn’t be a brown dwarf or “failed star.” And that means the object harboring this ancient gas giant is a white dwarf, an ultra-dense remnant of a sun-like star.
This planet is large, about 40 percent larger than Jupiter. Still, the team believes this might give us a glimpse of what our solar system will look like five billion years from now. Perhaps Jupiter will survive the cataclysm — maybe some of its moons will even make it. As the sun heats up, anyone alive on Earth might end up making a break for the moons of Jupiter, which could become quite temperate for a few hundred thousand years. There has also been speculation that Saturn’s moon, Titan might be warm enough to support life. The astronomers are looking forward to NASA’s Nancy Grace Roman Telescope, which should be able to image massive exoplanets like this one directly sometime in the mid-2020s. Then we might find it’s more or less like our little corner of the universe.
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