There could be planets hiding in Proxima Centauri’s space dust

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Nov 7, 2017

On Earth, dust means you need to get out the Swiffer again. In space, dust could mean a whole new planetary system.

These hypothetical planets, if they exist, are not orbiting that far from us—just four light-years away in the constellation Centaurus. Red dwarf star Proxima Centauri is already orbited by Proxima b, the closest known planet to the solar system. Except there could be more hiding in that shroud of space dust. Scientists have shed light on the glowing circle of dust surrounding Proxima Centauri as being the potential indication of a totally new system of planets that emerged from it billions of years ago.

“The dust around Proxima is important because, following the discovery of the terrestrial planet Proxima b, it’s the first indication of the presence of an elaborate planetary system, and not just a single planet, around the star closest to our Sun,” said Guillem Anglada, lead author of a study recently published in the Astrophysical Journal.

Dust belts are the birthplaces of planets. What remains are the fragments that, for some reason, didn’t conglomerate into larger celestial bodies. They can be swirling with anything from microscopic dust particles to planetesimals that could eventually be captured as moons or hurtle through the darkness as asteroids. This dust belt is about a hundredth of the Earth’s mass and is at least a hundred million miles from its star. At a temperature of about -382 degrees Fahrenheit, the same as the Kuiper belt on the fringe of our solar system, you’d need more than a space suit to keep from getting hypothermia if you were floating out there.

Proxmia Centauri from Hubble's POV.

Observations through the Atacama Large Millimeter Array (ALMA) revealed something that could be another belt of dust much further out and much more freezing (that is what happens when you get that far from a star that is already fainter and not nearly as fiery as the sun). If planets formed in this dust, they may still be hiding in it. Future exploratory ventures like Stephen Hawking’s Breakthrough Starshot Project could illuminate them further. Count on a visionary like Hawking to dream up a mission that blasts laser-driven sails with attached microprobes into the vicinity of Proxima Centuari, but first astronomers need to further study the spectral dust around the star.

“In combination with the study of protoplanetary discs around young stars, many of the details of the processes that led to the formation of the Earth and the Solar System about 4,600 million years ago will be unveiled,” said Anglada.

Looks like space dust has just been elevated to potential planetary discovery status.

(via ESO)