Faraway 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.

“It is entirely incomprehensible that a star that bright, and with such high proper motion, would have remained unnoticed,” the research team writes. Instead, they say the best explanation is that the object is in our own solar system, but orbiting at a distance that’s too far for detection in other wavelengths.

Distances to objects on the edge of our solar system are typically expressed in astronomical units, or AU, with 1 AU equal to the 93 million-mile distance between Earth and the sun. Among the possibilities cited in the paper are a dark, icy world that’s more than 100 AU away, or a super-Earth that’s about 300 AU away, or a super-cool brown dwarf that’s out in the Oort Cloud, 20,000 AU away.

Several strange objects already have been detected on the solar system’s edge – including Sedna and two more recently found worlds known as 2012 VP113 (a.k.a. Biden) and V774104. But this one would be super-strange, due to its larger size.

Even stranger, a study published in Nature last year suggested that just such an object just might exist. That would explain how objects like Sedna were thrown into their unusually distant and eccentric orbits.

The second study, also submitted to Astronomy & Astrophysics, reports the submillimeter-wave detection of an object in the same area of the sky as the star W Aquilae. This object has been given the provisional name Gna, after the mythological Norse goddess of the breeze. Woulter Vlemmings of Sweden’s Chalmers University of Technology, is a co-author for both studies.

Vlemmings and his colleagues say Gna could be an object with a size between 140 and 550 miles wide (220 to 880 kilometers wide), orbiting at a distance of 12 to 25 AU. That would make it what astronomers call a centaur object, somewhere between the orbits of Saturn and Neptune. Or, they say, it could be a planet-sized object or a brown dwarf far beyond Sedna, at a distance of about 4,000 AU.

The newly posted reports feed into long-running claims that an unseen Planet X could be lurking somewhere on the edge of the solar system. And as you’d expect, the ALMA studies have generated a flurry of buzz and a hail of skepticism.

Even the researchers behind the Gna paper acknowledge, in a backhanded way, that there may be “yet unknown, but significant, issues with ALMA observations.” Caltech astronomer Mike Brown, one of the discoverers of Sedna, voiced even stronger doubt in a series of tweets late Wednesday:

Phil Plait, the astronomer behind Slate’s Bad Astronomy blog and author of “Death From the Skies: The Science Behind the End of the World,” joined in the happy thoughts:

“Well, it would sell a lot of books, for a little while at least,” Plait cracked.

Check out Plait’s take on the studies, as well as Eric Berger’s report for Ars Technica and Brian Koberlein’s report for Forbes. Lee Billings’ report for Scientific American includes follow-up comments from critics as well as from Vlemmings.

Like previous claims about faster-than-light neutrinos, the ALMA readings could turn out to be nothing more than observational glitches. But until then … watch the skies!

In addition to Vlemmings, the authors of “A New Submm Source Within a Few Arcseconds of Alpha Centauri: ALMA Discovers the Most Distant Object of the Solar System” include R. Liseau, E. O’Gorman, E. Bertone, M. Chavez and V. De la Luz. Vlemming’s co-authors for the other study, “The Serendipitous Discovery of a Possible New Solar System Object With ALMA,” are S. Ramstedt, M. Maercker and B. Davidsson.

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