A team of scientists at Complutense University of Madrid reports new evidence of a giant planet ten times the mass of the Earth lurking deep in the outer solar system, at a distance of 700 AU (astronomical units, with one AU equal to 93 million miles, or the average Earth-Sun distance) from the Sun.
The prospect of a super-Earth orbiting at such a great distance was initially proposed in January 2016 by a group of astronomers at the California Institute of Technology (Caltech) based on the unusual orbits of distant Kuiper Belt Objects.
However, that object was never found, and researchers with the Outer Solar System Survey Origins Study (OSSOS) said they detected biases in the Caltech team’s observations and also determined that the unusual orbits of the KBOs in question could be explained without the influence of a giant planet.
Using a new technique less vulnerable to researcher bias, the Madrid scientists focused on a group of KBOs 150 AU or further from the Sun, none of which cross the orbit of Neptune.
Specifically, they studied the distances from these objects’ nodes, the two points at which they cross the plane of the solar system, to the Sun.
If a KBO interacts with any other object, that interaction is most likely to occur at one of these two points.
Mathematical calculations show the nodes of many of these KBOs, also known as Extreme Trans-Neptunian Objects (ETNOs) because of their extremely elliptical orbits, are clustered at various ranges of distances from the Sun.
For many of these KBOs, the researchers also found a correlation between the positions of their nodes and their orbital inclinations, which should not exist.
“Assuming that the ETNOs are dynamically similar to the comets that interact with Jupiter, we interpret these results as signs of the presence of a planet that is actively interacting with them in a range of distances from 300 to 400 AU,” said Carlos de la Fuente Marcos, co-author of a study on the findings published in the Monthly Notices of the Royal Astronomical Society Letters (MNRAS).
“We believe that what we are seeing here cannot be attributed to the presence of observational bias.”
The hypothetical planet proposed by the researchers is not the supposed Mars-sized planet that scientists Kathryn Volk and Renu Malhotra suspect to be located around 60 AU from the Sun.