A Jupiter-sized planet has been discovered orbiting a dead star and this may provide scientists with valuable information regarding what will happen when our own sun will eventually die in approximately 5 billion years.
The giant exoplanet is orbiting a white dwarf about 6,500 light-years away from us close to the center of our Milky Way Galaxy. The planet is approximately 40% larger than Jupiter and the white dwarf has about 60% of the mass of our sun.
When a sun-like star expands into a red giant, it burns through all of its hydrogen fuel and swells up. During this phase, it destroys any planets that are close to it. When the star no longer has an atmosphere, there is nothing left but a collapsed core which is called a white dwarf.
The fact that a planet was found still orbiting a white dwarf at a decently close range is baffling as it should have been destroyed. However, upon further analysis, researchers realized that the star and the planet formed at the same time. The planet is located approximately 2.8 astronomical units (AU) away from the white dwarf (one AU is the distance of Earth to our sun).
While it was thought that giant planets had to be situated a lot further away from the white dwarf in order to survive, this new discovery contradicts that theory. And it may not just be giant planets that can survive and still orbit white dwarfs and there may possibly be even smaller worlds doing the same thing.
So, what does that mean for our Solar System in 5 billion years? Joshua Blackman, who is an astronomy postdoctoral researcher at the University of Tasmania in Australia, explained, “This evidence confirms that planets orbiting at a large enough distance can continue to exist after their star's death,” adding, “Given that this system is an analog to our own solar system, it suggests that Jupiter and Saturn might survive the Sun's red giant phase, when it runs out of nuclear fuel and self-destructs.”
While Jupiter and Saturn may be safe, the inner planets – Mercury, Venus, and possibly Earth – will probably be engulfed by the sun when it becomes a red giant. “Earth's future may not be so rosy because it is much closer to the Sun,” noted David Bennett who is a senior research scientist at the University of Maryland and NASA's Goddard Space Flight Center, adding, “If humankind wanted to move to a moon of Jupiter or Saturn before the Sun fried the Earth during its red supergiant phase, we'd still remain in orbit around the Sun, although we would not be able to rely on heat from the Sun as a white dwarf for very long.”
Well, at least it won’t happen for about another 5 billion years so we’re safe for now. Their research was published in Nature.