Dust suggests Proxima Centauri b isn’t alone

Dust belt at Proxima
An artist’s impression shows the newly discovered belts of dust around Proxima Centauri, the closest star to our solar system. This sketch is not to scale — to make Proxima b clearly visible, it has been shown farther from the star and larger than it is in reality. (ESO Illustration / M. Kornmesser)

Astronomers created a stir last year when they reported that the closest star beyond our own solar system harbors a potentially habitable planet, but now fresh evidence hints that there could be even more worlds around Proxima Centauri.

The ALMA Observatory’s array of antennas in Chile has picked up the thermal glow from cold clouds of dust surrounding the red dwarf star, which lies just 4.2 light-years away in the constellation Centaurus. The clouds show up in a region that’s about one to four times as far away from the star as Earth is from our own sun.

There’s also evidence of a second dust belt farther out from the star. Such belts are thought to contain the remains of material left behind by the planet formation process, consisting of particles ranging in size from flecks of earthly dust to miles-wide asteroids.

Both belts are farther out than Proxima Centauri b, the planet whose detection was announced last year.

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Planet X? Probably not, despite the buzz

Image: Distant world
An artist’s conception shows the dwarf planet Eris. Astronomers say an even larger world may exist on the solar system’s edge. (Credit: NASA / JPL / Caltech)

An array of radio telescopes in Chile has picked up weird readings that appear to be coming from far-out objects – and that’s sparked a debate over whether they’re previously undetected worlds on the edge of our solar system, brown dwarfs, or just random glitches.

Readings from the Atacama Large Millimeter/Submillimeter Array, or ALMA, have led to the posting of at least two research papers on the arXiv pre-print server. Historically, some of the studies that scientists post to arXiv go on to make a splash, while others fizzle out.

One study, submitted to the journal Astronomy & Astrophysics, reports detecting an object in submillimeter wavelengths that’s close to the same position in the sky as the Alpha Centauri binary-star system, and moving along with it.

Could it be yet another star associated with Alpha Centauri? The researchers rule out that scenario on the grounds that it hasn’t been seen before in other wavelengths.

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