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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Tiny probes get tested for interstellar mission

Yuri Milner and Sprite
Russian billionaire Yuri Milner holds a “Sprite” mini-probe like the ones that are being tested in low Earth orbit. (Breakthrough Starshot via YouTube / SciNews)

Breakthrough Starshot says it’s been testing prototype interstellar spacecraft no bigger than postage stamps in orbit for the past month, and they seem to be working just fine.

Six of the 1.4-inch-square circuit boards, dubbed “Sprites,” were launched into low Earth orbit on June 23 as tiny piggyback payloads on two nanosatellites. Those educational satellites, Max Valier Sat and Venta 1, were developed with the aid of German-based OHB System and launched by an Indian PSLV rocket. (Seattle-based Spaceflight played a role in launch logistics.)

In a statement issued today, Breakthrough Starshot said the Sprites are still attached to the nanosatellites and are “performing as designed.” The Sprite radio communication system is in contact with ground stations in California and New York, as well as with amateur radio enthusiasts around the world.

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Why it’ll take years to see what Proxima b is like

Image: Proxima Centauri b
An artist’s conception shows a view of the surface of the planet Proxima b, with the red dwarf Proxima Centauri near the horizon. (Credi:t: M. Kornmesser / ESO)

University of Washington astronomer Rory Barnes says Proxima Centauri b is the biggest discovery in 20 years for planet hunters like himself, but it could take another 20 years to find out just how livable it is.

The alien planet orbits a red-dwarf star at a distance that puts it in a zone where liquid water could conceivably exist. The fact that such a world circles the sun’s nearest stellar neighbor, 4.2 light-years away, puts it on top of the list of potentially habitable planets beyond our solar system.

Barnes, however, emphasizes the word “potentially.” During a lecture at Seattle’s Pacific Science Center, set for 7:30 p.m. tonight, the UW astronomer will delve into the opportunities and obstacles for life on Proxima Centauri b.

“We’re looking at a 15- to 20-year time frame before we can answer this question of whether it’s habitable,” Barnes told GeekWire in advance of the talk.

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Potentially habitable planet at the star next door

Proxima Centauri b
An artist’s conception shows Proxima Centauri b orbiting its parent star, a red dwarf, with the two other stars of the Alpha Centauri system in the far background. (Credit: M. Kornmesser / ESO)

The rumors you’ve heard are mostly true: Scientists say the star that’s closest to our solar system has a planet that could be at the right temperature for liquid water and life.

The star is called Proxima Centauri, a red dwarf that’s part of the Alpha Centauri system, 4.2 light-years away. The planet is called Proxima Centauri b, and it’s a terrestrial world whose existence has now been confirmed after 16 years of study.

It’s not yet known whether Proxima b has an atmosphere, or liquid water. But the computer models don’t rule out the possibility. That would make it the closest known exoplanet – and the closest known exoplanet with the potential for life.

As such, it could be the nearest haven for humanity in case things go horribly wrong in our own solar system. And it just so happens that scientists are working on a robotic mission to the Alpha Centauri system: The Breakthrough Starshot initiative received a $100 million kick-start from Russian billionaire Yuri Milner in April.

“We expect either to characterize it, if we get lucky, or maybe visit it in a couple of centuries,” Guillem Anglada-Escude, an astronomer at Queen Mary University of London, told reporters.

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