For quite a while we’ve known that another star is heading our way, and now astronomers have not only confirmed that prediction, but said it’ll be closer and sooner (a bit) than we thought.
The star is called Gliese 710, which is about 60 percent the mass of our Sun. It’s a dwarf star that, in a bit over a million years, will come within a fifth of a light-year of our Solar System.
At that distance, it is some cause for concern, as it will be well within the Oort cloud – a vast cloud of comets that surrounds our Sun up to a light-year away. It’s possible it could send some of these comets flying inwards towards the planets, or even disturb the planets with its gravitational pull.
Thanks to the first batch of data from the European Space Agency’s Gaia space observatory, astronomers Filip Berski and Piotr Dybczyński were able to refine this prediction in 2016. They said it would make its closest approach in 1.35 million years, at a distance of 0.25 light-years, or 16,000 times the Earth-Sun distance.
But now that the second batch of data is out, two astronomers have refined this even further. In a short paper published on arXiv, astronomers Raul de la Fuente Marcos and Carlos de la Fuente Marcos from the University of Madrid say the star is going to come closer and sooner.
Their calculations suggest it will brush the Solar System in about 1.29 million years, at a distance of just 0.07 light-years. That’s just over 4,000 times further than Earth is from the Sun, and just 100 times further than the orbit of Pluto.
“Our results… suggest a closer, both in terms of distance and time, flyby of Gliese 710 to the solar system,” the researchers wrote in their paper. While they say that the star is unlikely to have a gravitational effect on the planets, the close approach “may trigger a major comet shower that will affect the inner solar system.”
Interestingly, the team came up with a model for calculating the close approach by looking at another that happened not too long ago. About 70,000 years ago, it’s thought that a red dwarf star came within a light-year of our Solar System, possibly visible to ancients. Called Scholz’s Star, it helped them refine their calculations for Gliese 710.
At the moment, the star is 62 light-years from us, so it’s certainly not having any effect at the moment. But it looks like in the distant future our descendants may well have to contend with this close passage. Let's hope they’ve got the means to survive anything it throws at them.