Small red star perturbed solar system's comets about 70,000 years ago

When it entered the Oort Cloud, the star altered the trajectories of some objects that have hyperbolic orbits.
By Laurel Kornfeld | May 22, 2018
A small red star passed within one light year of the Sun 70,000 years ago, when prehistoric humans were already on Earth, and perturbed the orbits of some comets and asteroids in the solar system.

Scholz's star, which is now nearly 20 light years away, entered the Oort Cloud, a spherical region of long period comets, at that time, altering their trajectories.

Named for the German astronomer who discovered it, the star is part of a binary system along with a brown dwarf. It has just nine percent the mass of our Sun.

The star's passage and its effects were first noted publicly by a research team led by Eric Mamajek of the University of Rochester in 2015 and documented in a paper published in Astrophysical Journal Letters.

Following up on that paper, researchers Carlos de la Fuente Marcos, Raul de la Fuente Marcos, and Sverre J. Aarseth, all of the University of Cambridge in the UK, analyzed 340 solar system objects that have open, V-shaped orbits known as hyperbolic orbits, and found evidence their paths were altered by the close passage of Scholz's star.

"Using numerical simulations, we have calculated the radiants or positions in the sky from which all these hyperbolic orbits seem to come," Carlos de la Fuente Marcos said.

Without the star's influence, these solar system objects would be evenly distributed in the sky. Instead, many appear to be clustered in the direction of the constellation Gemini, which matches the star's trajectory.

"It could be a coincidence, but it is unlikely that both location and time are compatible," he emphasized.

Computer simulations indicate Scholz's star came within less than 0.6 light years of the solar system, he added.

Passage of the star did not affect all solar system objects with hyperbolic orbits, just those close to the area the star traversed.

Ancient humans may have seen a reddish glow from the star in their night sky.

Findings of the study have been published in Monthly Notices of the Royal Astronomical Society.


We are dedicated to maintaining a respectful community that actively engages in lively discussions about news stories and blog posts. Please keep the following in mind when writing your comments.