Analysis of four ice bodies found in the outer solar system revealed no signs of being influenced by a large, invisible planet lurking behind Neptune's orbit. This fact speaks against the series of evidence proposed in 2014 based on the clustering of objects in the Kuiper belt region. The work of astronomers appeared late last week in arXiv.
These objects were discovered by scientists conducting the OSSOS (Outer Solar System Origin Survey) survey, which explored regions of space beyond Neptune.
Using the 3.6-meter Canada-France-Hawaii telescope on Mauna Kea, scientists have discovered four bodies that revolve around the Sun in huge ellipses of 250 astronomical units (AU). An astronomical unit is equivalent to the distance between the Earth and the Sun; Neptune's orbit is about 30 AU. e. At the moment, about 12 bodies with a large orbit have been detected, including 4 found by OSSOS.
The case for a ninth planet builds on the aggregation of six previously known large-orbiting objects. Research from two other groups has shown that these six bodies are organized into two groups. Both teams suggested that the gravity of an invisible planet, which is ten times the size of Earth, arranges these objects into interesting shapes.
Disappearing clusters
Scientists agree that the astronomical surveys that revealed these six bodies were not perfect, says Corey Shankman, an astronomer at Victoria University in Canada and lead author of the newest study. They all dealt with limited visibility due to poor weather and the fact that Kuiper belt objects are easier to see outside the plane of the Milky Way. These factors can cause astronomers to find more bodies in certain regions of the sky than others, even when objects are evenly distributed, Shankman says. It is possible to account for these discrepancies using statistical methods, but no one has done so for the most part.
The OSSOS team argues that the bias could lead to false readings of clustering. "They have built this argument around six objects with an incomprehensible bias in the detection process," says astronomer Samantha Lawler of the National Research Council of Canada, "and this is a very dangerous game."
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Three objects discovered by OSSOS were previously represented in these two clusters. But when the authors of the study began to consider the fact that the survey previously found dotted bodies in a certain part of the sky at a certain time of the year, the data on clustering disappeared, says Shankman.
Planet Nine Affair
Unknown biases in previous surveys have indeed weakened planet nine's position in terms of proposed sizes and distances, says Renu Malhotra, an astronomer at the University of Arizona in Tucson. But the OSSOS team has not proven that these biases actually remove the clustering of distant Kuiper belt objects, so the work does not stop the discussion process.
Scott Sheppard, an astronomer at the Carnegie Institute of Science in Washington and member of the team that first found signs of an invisible planet, agrees. Even this new data doesn't explain the strange clustering of Kuiper Belt objects - as long as the planet remains the best option.
And even if previous surveys had problems, they did find signs of the possible existence of a massive planet, says Konstantin Batygin, an astronomer at the California Institute of Technology in Pasadena and a member of another team that suggested the existence of a ninth planet.
Moreover, clustering is just one chain of evidence for planet nine. The discovery of Kuiper belt objects that are not tied to Neptune and others with orbits almost perpendicular to the orbits of most objects in the solar system are most easily explained by the presence of a large planet in the outer solar system.
More data from current and future telescopes is needed to ultimately resolve the issue of planet nine, Malhotra says. “We are working on the brink of technical capabilities with the outer solar system. So far we are only pushing the boundaries of what can be found."
ILYA KHEL