Astronomers reported observing a fascinating peek of the afterlife of our solar system: a Jupiter-sized planet orbiting a white dwarf 6,500 light years away, in the journal Nature on Wednesday.
When our sun dies in around 5 billion years, it will incinerate our planet before collapsing into a lifeless ember known as a white dwarf. However, the fate of more distant planets such as Jupiter and Saturn is less certain.
The newly discovered planet, known as MOA-2010-BLG-477Lb, has a similar orbit as Jupiter. The revelation not only provides a view into our cosmic future, but it also raises the prospect that any life on ‘survivor’ worlds may be forced to suffer the deaths of their stars.
Joshua Blackman, a postdoctoral researcher at the University of Tasmania and the study’s primary author, said that while there are lots of evidences of rocky planetary debris that orbit white dwarfs, there are very few data points of entire planets.
Our solar system is likely to be similar to the planetary system in which MOA-2010-BLG-477Lb belongs. The sun will become a white dwarf, the inner planets will be consumed, and the planets with a larger orbit, such as Jupiter and Saturn, will survive, Joshua Blackman wrote in an email.
The planet was discovered due to the gravitational field’s light-warping effects, a phenomenon known as microlensing. After years of hunting for its host star with the Keck II telescope in Hawaii, Blackman and his colleagues decided that it was orbiting a white dwarf that was too dim to view directly.
Last year, astronomers discovered another entire Jupiter-like planet, known as WD 1856 b, orbiting a white dwarf, using a different method. MOA-2010-BLG-477Lb orbits its concealed stellar shell at roughly three times the distance between Earth and the sun, making it the first known planet to orbit a white dwarf in a Jupiter-like orbit. WD 1856 b, on the other hand, orbits its white dwarf every 1.4 days, implying that it migrated into its current position after its star died, but the exact physics of that journey are still being worked out.
Andrew Vanderburg, an assistant professor of physics at the Massachusetts Institute of Technology who led the team that found WD 1856 b, said that the conclusions of the current study were robust. He also mentioned that planets with wide orbits around white dwarfs were likely to be more abundant than those with tight orbits, but the latter were easier to discover.
Vandenburg added that if he had to guess, I would say that they were a much more frequent population because they just had to stay there and had nothing happen to them, and at that stage in the universe’s history, that seemed to me to be the most plausible scenario.
The new findings may provide light on the search for extra-terrestrial life as well as the possible habitability of white dwarf systems. Lisa Kaltenegger, head of Cornell University’s Carl Sagan Institute, has proposed that some life-bearing star systems may even undergo a ‘second genesis,’ in which new species emerge from the altered debris of a white dwarf system.