NYC Gazette

Objects from interstellar space, such as rogue planets and asteroids, can become permanently trapped in the Sun’s orbit due to the combined gravitational effects of the Sun and the Milky Way galaxy, according to a study by researchers at Katz School’s Mathematical Sciences program and NASA.

In March, Edward Belbruno, professor of mathematics at the Katz School, discussed the results of this study at Heidelberg University and with the trajectory dynamics group at the European Space Agency's Operations Centre (ESOC) in Germany. In his paper titled "Permanent Capture into the Solar System," he explained that when an object from interstellar space is caught by the Sun’s gravitational pull, it can enter a state known as permanent capture. In this state, the object remains in orbit around the Sun indefinitely without escaping back into space or colliding with it.

Belbruno described another state called weak capture where an object is slowly drawn into a stable orbit around the Sun but never fully reaches it. This ensures its perpetual presence in the solar system. The region where this capture occurs exhibits a complex repeating pattern similar to a fractal, contributing to the stability of the captured object's orbit.

“The combined gravitational forces of the Sun and the Milky Way play a crucial role in this process,” said Belbruno. “The galaxy’s gravitational field, including dark matter effects, significantly influences how objects are captured. Previous studies mainly focused on comet captures which weren’t always permanent. This new research describes a mechanism that ensures permanent capture.”

Belbruno and James Green of NASA used a simplified model involving three masses: an interstellar object, the Sun, and a representation of the Milky Way’s mass. This model simulated both motion and stability of captured objects exhibiting chaotic behavior akin to patterns seen in mathematical constructs like Mandelbrot sets.

The study suggests that rogue planets could be captured by our Sun over millions of years potentially influencing existing planetary orbits within our solar system. These changes could make such rogue planets detectable by scientists through observable orbital perturbations.

“The discovery not only enhances our understanding of gravitational dynamics but also opens up new possibilities for detecting and studying these fascinating celestial bodies,” said Belbruno. “As we continue to explore cosmos who knows what other secrets universe holds about objects joining our solar family?”