Tunisie Soir (Tunísia)

A population of asteroids of interstellar origin inhabits the Solar System

Publicado em 20 julho 2020

Por EurekAlert!

A study conducted by scientists at São Paulo State University's Institute of Geosciences and Exact Sciences (IGCE-UNESP) in Rio Claro, Brazil, has identified 19 asteroids of interstellar origin classified as Centaurs, outer Solar System objects that revolve around the Sun in the region between the orbits of Jupiter and Neptune.

An article on the study is published in the Royal Astronomical Society's Monthly Notices ("An interstellar origin for high-inclination Centaurs"). The study was supported by São Paulo Research Foundation (FAPESP).

Composition made by the researcher of an artistic image from NASA used to show what the primordial solar system would be like, with the addition of a Centaur in polar orbit in the outer region. (Image: Maria Helena Moreira Morais)

"The Solar System formed 4.5 billion years ago in a stellar nursery, with its systems of planets and asteroids. The stars were close enough to each other to foster strong gravitational interactions that led to an exchange of material among the systems. Some objects now in the Solar System must therefore have formed around other stars. Until recently, however, we couldn't distinguish between captured interstellar objects and objects that formed around the Sun. The first identification was made by us in 2018," Maria Helena Moreira Morais , one of the two coauthors, told.

Morais graduated in physics and applied mathematics from the University of Porto (Portugal) and earned a PhD in Solar System dynamics from the University of London (UK). She is currently a professor at IGCE-UNESP. The other coauthor is Fathi Namouni, a researcher at Côte d'Azur Observatory in Nice, France.

The first identification to which Morais referred was the asteroid 514107 Ka'epaoka'awela.

The name Ka'epaoka'awela is Hawaiian and can be roughly translated to "mischievous opposite-moving companion of Jupiter". It has occupied the path corresponding to Jupiter's orbit for at least 4.5 billion years but revolves around the Sun in the direction opposite to that of the…