Approximately 70,000 years ago, when humanity was already on Earth, a small reddish star approached our solar system: we know it as Scholz’s star and its passage gravitationally disturbed comets and asteroids of the prehistoric solar system.
Now, a team of astronomers from the Complutense University of Madrid (Spain) has verified that the movement of some of these cosmic objects is still influenced by that stellar encounter.
Scholz, at just 9% the mass of our own Sun, was not very large. Hence when astronomers discovered in 2015 that this star had skimmed our neighborhood, they assumed that it would not have had much of an effect on our Solar System. However, reviewing the positions of the Oort Cloud objects, a team of Spanish researchers together with experts from the University of Cambridge (United Kingdom) have shown that this is not the case and that we can still see the impact of their visit to today.
And it is that this prehistoric encounter left weak gravitational traces in the extreme outer limits of our solar system.
To reach this conclusion, the astronomers analyzed the positions of about 340 objects in the solar system with hyperbolic orbits (very open V-shapes, not the typical elliptical ones), and in doing so they detected that the trajectory of some of them (several dozen) it was influenced by the passage of Scholz’s star.
The star altered some trans-Neptunian objects
“ In principle, one would expect those positions to be evenly distributed in the sky, particularly if these objects come from the Oort cloud. However, what we find is very different: a statistically significant accumulation of radiants. The overdensity plus The accused appears projected in the direction of the Gemini constellation, which is consistent with the close encounter with Scholz’s star, “explains Carlos de la Fuente Marcos, co-author of the work.
It could be a coincidence, but it is unlikely. The moment in which this star passed near us and its position during prehistory coincide in the data of the new research and with those of the discovery of the star in 2015 by the University of Rochester (United Kingdom).
It is possible that our ancient stargazers notice in the star’s dull red glow . But what they would not have seen is a small companion in its orbit: a dwarf star. And the fact is that Scholz’s star is actually a double system formed by a small red dwarf, around which a smaller and much less bright brown dwarf orbits.
Although this is pure speculation, some astronomers have suggested that a dark twin of our own Sun could have caused some alterations when it happened 65 million years ago, just when a piece of rock made life much more difficult for the dinosaurs. In comparison, the passage of the Scholz binary system was incredibly subtle.
Still, work on how our stellar neighbors affect our solar system could have significant implications for potential future encounters.
Reference: C. de la Fuente Marcos, R. de la Fuente Marcos, SJ Aarseth. “Where the Solar system meets the solar neighborhood: patterns in the distribution of radiants of observed hyperbolic minor bodies”. MNRAS Letters , 2018. DOI: https://doi.org/10.1093/mnrasl/sly019
http://adsabs.harvard.edu/abs/2018MNRAS.476L…1D
Image credit: José A. Peñas / SINC
