Main Question or Discussion Point
Below is the arXiv free reprint being referenced by the above magazine article. Ironically, they were using ALMA in order to attempt to confirm the exoplanet previously found orbiting Alpha Centauri B when this object was discovered.A super-Earth in our solar system? Not so fast.
Astronomers quietly submitted a research paper claiming they may have found a large planet on the far fringes of our solar system.
Astronomers working with the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered what they claim could be another large planet on the fringes of our solar system.
Source: Astronomy Magazine
The brighter the object the more likely it would have been discovered previously. In order to be roughly the same distance as the Alpha Centauri system, 1.34 parsecs away, the object would have to be an M2 star. Which seems very unlikely that it would remain undiscovered until now.Curiously, when we examined a total of 766,925 known solar-system objects for being within 15' around α Cen at the time of observation, we found no source down to the limiting V-magnitude of 26.0.
What confuses me is why this object would need to be as large as a "super-Earth" or Brown Dwarf? Could it not also be considerably smaller, say on the order of a Pluto-sized object for example, and be much closer? In order to be the size of a Brown Dwarf it would have to have an orbit of ≈20,000 AU according to the temperature-distance diagram they provided in their paper (referenced below), which seems to be a bit extreme. To be a "super-Earth" the object would need to have an orbit of ≈300 AU. My question is, could not the object be considerably smaller, and therefore much closer - similar to Sedna or Pluto in size and at distance of ≈100 AU?
This is certainly going to feed the Nemesis believers if it is confirmed that this object is as large as they suspect.
A new submm source within a few arcseconds of α Centauri: ALMA discovers the most distant object of the solar system - arXiv 1512.02652v1