With recent advances in imaging technology pushing the boundaries of astronomy and space exploration more rapidly than ever before, new discoveries within the solar system and beyond are now being made at a breakneck pace. Part of that exploration has been for the elusive Planet X, a theorized large trans-Neptunian world that has otherwise eluded attempts at detection. Until now, only smaller planetoids have been discovered in the deep dark of space, but two new findings hold promise as new candidates for the title of Planet X.
The announcement of these two candidates, one found in the direction of Alpha Centauri, the other in the direction of W Aquila, was made in two separate papers submitted to the Astronomy & Astrophysics journal. The papers have not yet been formally peer-reviewed, but were released by the researchers to initiate a discussion on the topic. According to co-author and Chalmers University of Technology astronomer Wouter Vlemmings, "We specifically wanted to reach the community that could tell us if we overlooked something, in which case we fully intend to withdraw the papers."
The W Aquila object has been tentatively named "Gna" by Vlemmings’ team, after the Nordic messenger goddess. They estimate that Gna is at a distance of 12 to 25 AU, and is 220 to 880 km in size. Alternatively, they also theorize that the object could be as far out as 4,000 AU, of which would make it a large, planet-sized object.
The team has fewer estimates about the Alpha Centauri object, as they still need to gather more data: the object could be a small object at 100 AU, a "Super-Earth" at 300 AU, or a cool brown dwarf that is much farther out.