The Case for an Early Solar Binary Companion

Abstract

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 LSST, with similar orbits to Planet Nine, which would result from capture by the stellar binary.

5 pages, 2 figures; accepted to ApJL

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Cited by in corpus (6)

• Oort cloud Ecology II: The chronology of the formation of the Oort cloud
• Encounters involving planetary systems in birth environments: the significant role of binaries
• Interstellar Objects Outnumber Solar System Objects in the Oort Cloud
• Inclination Excitation of Solar System Debris Disk due to Stellar Flybys
• Outer Solar System Perihelion Gap Formation Through Interactions with a Hypothetical Distant Giant Planet
• Dynamical Fates of S-Type Planetary Systems in Embedded Cluster Environments