# The Case for an Early Solar Binary Companion

@article{Siraj2020TheCF,
title={The Case for an Early Solar Binary Companion},
author={Amir Siraj and A. Loeb},
journal={arXiv: Earth and Planetary Astrophysics},
year={2020}
}
• Published 2020
• Physics
• arXiv: Earth and Planetary Astrophysics
We show that an equal-mass, temporary binary companion to the Sun in the solar birth cluster at a separation of $\sim 10^3 \; \mathrm{\; AU}$ would have increased the likelihood of forming the observed population of outer Oort cloud objects and of capturing Planet Nine. In particular, the discovery of a captured origin for Planet Nine would favor our binary model by an order of magnitude relative to a lone stellar history. Our model predicts an overabundance of dwarf planets, discoverable by… Expand
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