Artist's impression of a young binary system. Scientists believe that our Sun might have a twin star. Credit: NASA

Our Sun Likely Had a Twin, And Was Responsible For The Extinction of Dinosaurs

The hypothesis suggests that Nemesis could travel through the Solar System's outer limits, thus affecting the objects within with its gravity.


Astronomers have suggested that most stars form with at least one twin and our Sun is unlikely to be an exception. Scientists predicted the existence of a theoretical twin dubbed Nemesis, which is incredibly dim and located at a great distance from our planet.

This is the reason that the star has not been detected until today, but at the same time, it might have a strong enough effect on our Solar System.

Scientists suggest that all Sun-like stars form with twins and our Sun is not an exception

Do all stars form as binaries?

The conclusion that stars resembling the Sun are born with twins was made after a careful study of a dust cloud located in the constellation Perseus. It is located at a fairly large distance from Earth at about 600 light-years and astronomers found a huge number of young stars.

Scientists divided stars into two separate groups based on age. The first group includes objects of Class 0, the age of which does not exceed 500 thousand years. The age of the second Class 1 is in the range from 500 thousand to 1 million years.

Further analysis showed that young stars in binary systems are located at a distance of about 500 astronomical units. In turn, older objects are located at a distance of no more than 200 astronomical units. Researchers noted that at the moment it remains unclear how the evolution of distant double-type stellar systems occurs but it is not at random.

The main fact here is that the data obtained was reproduced by just a single model – the one that states that all stars form as wide binaries. So, if this is true, then where is the twin of our own star – the Sun?

The theoretical twin star of our Sun

The hypothesis about the theoretical star dubbed Nemesis has been around for a while and it is often pointed to as the likely reason for the periodical extinction on our planet. In fact, scientists have suggested that it might be what caused the end of the dinosaurs. But how exactly?

The hypothesis suggests that Nemesis might pass through the Solar System’s outer limits, thus affecting the objects within with its gravity. This influence could attract huge asteroids and send them inwards in the system and certain scientists have hypothesized that this could have been the reason for the Chicxulub asteroid.

Where is Nemesis?

Interestingly, a scientist proposed that a red dwarf star could travel through our system more than 20 years ago. Only now did scientists find convincing evidence about the formation of stars that could provide some insight into such a theory.

For now, there is no sign of the twin star but theoretically, its existence fits the models and could explain some of the oddest anomalies in the Solar System like the weird orbits of distant dwarf planets and more.

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Dimopoulos, K. (2021, October 6). Did ‘dark matter’ or a star called Nemesis kill the dinosaurs? The Conversation.
Letzter, R. (2020, August 31). The Sun may have a long-lost twin. LiveScience.
McRae, M. (n.d.). Our sun may have been born with a trouble-making twin called ‘nemesis’. ScienceAlert.
Sadavoy, S. I. (n.d.). Embedded binaries and their dense cores .
Sanders, R. (2017, June 15). New evidence that all stars are born in pairs. Berkeley News.


Written by Vladislav Tchakarov

Hello, my name is Vladislav and I am glad to have you here on Curiosmos. As a history student, I have a strong passion for history and science, and the opportunity to research and write in this field on a daily basis is a dream come true.

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