New research suggests that a dust belt may be circling the closest star to the Sun, a red dwarf named Proxima Centauri.
Guillem Anglada at the Institute of Astrophysics of Andalucía in Granada, Spain, led the work (PDF), which was accepted for publication last week in Astrophysical Journal Letters. He told The Register a belt could help scientists better understand the system and the planets inside it.
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In 2016, boffins found strong evidence for a terrestrial planet orbiting Proxima Centauri: Proxima Centauri b. Although scientists in August determined that it was unlikely to be habitable, there's still plenty of star-gazing going on.
And this time it has unearthed some, er, dust. Dust belts are what's left over after planets grow up - they're a collection of dust and bodies, bumping around in space, which are not big enough to form planets.
Mark Wyatt of Cambridge University, who was not involved in the study, told The Register: "Studying the dust in this system provides extra information about the planetary system, both about where there may be planets that have yet to be found, and about how the planetary system formed and evolved."
He added: "It’s like going from only knowing that the Solar System has one planet orbiting it (the Earth) to saying that it also has an asteroid belt and an outer belt of comets (the Kuiper belt)."
In the new research, "ALMA Discovery of dust belts around Proxima Centauri", the researchers used the ALMA detector to observe radio waves that indicated dust. Normally, when mass is heated by a star it emits radiation. When it's cool enough, though, it emits radio waves.
First, the researchers captured low-resolution images that revealed radio wave emissions at a distance of less than four times the distance from the Earth to the Sun, indicating cold mass.
"It is clear that material is there," Anglada said.
Then, the researchers captured high-resolution imagery for about 2.5 hours. Because the instrument was not sensitive enough, they were unable to see the emissions at this resolution without degrading the image quality, he said.
But by using these images and making some calculations using the sensitivity of the device, they estimated that the dust would have been present at distances of greater than a single Earth-Sun distance away from Proxima Centauri. So the dust would probably be somewhere between one and four Earth-Sun distances from the star.
Anglada cautioned that the team is working on getting high-resolution observations for about five to seven hours to be sure.
But if true, he said the belt could help scientists create clearer pictures of the system or more precisely understand the masses of planets inside, by acting as a means of orientation. ®
*Forgive us, Latin scholars.