Neptune was discovered after the orbit of Uranus was found to depart from expectations in a manner that indicated that it was impacted by a large object. Neptune has been found almost exactly to orbit such a large object. There is a similar issue today with some objects in the Kuiper belt, which lead scientists to argue that a "Planet Nine" has an effect on their orbits.
Yet this Planet Nine - also called Planet X, Giant Planet Five, or Planet Next - remains elusive, although some studies are also unable to rule out its existence. And finding it may need looking at observatory images from a different perspective.
Astronomers are placing their bets on a technique they call "shifting and stacking," which may help track down the mysterious world some scientists say lurks in the far outer system, beyond Pluto's orbit.
The approach involves moving images of the space-telescope around collections of potential orbital paths, then piling the pictures together to blend their illumination. To find any moons in our solar system, the method works great, and it might theoretically detect Planet Nine and other very far-flung objects, researchers said.
"You really can't see them without using this kind of method," Malena Rice, an astronomy Ph.D. student at Yale University in Connecticut, said in a statement. "If Planet Nine is out there, it's going to be incredibly dim."
Rice is the lead author of the latest study that brings the technique into practice. She and co-author Greg Laughlin, a professor of astronomy at Yale, shifted and stacked images taken from Earth orbit by NASA's Transiting Exoplanet Survey Satellite (TESS), searching for alien planets.
In a survey, the researchers found in shifted and stacked TESS images the faint signals of three known trans-Neptunian objects (TNOs) - small bodies that surround the sun outside Neptune's orbit. A blind search of two remote sky patches was then undertaken by the researchers, turning up 17 new TNO candidates.
The researchers are currently working to validate the 17 candidate TNOs using ground-based telescope collected imagery.
TNOs are bread crumbs that could contribute to the discovery of Planet Nine. Scientists have concluded from the unusual orbits of certain TNOs the hypothetical world's life, which they claim are clustered in a way that clearly indicates sculpting by a huge, far-flung "perturber." The data shows a planet five to 10 times more massive than Earth, orbiting the sun hundreds of times farther away than our planet does.
The Planetary Science Journal has approved the new research. On Oct. 27, Rice presented the findings at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society, which is being held virtually this year.
