The Generation of the Distant Kuiper Belt by Planet Nine from an Initially Broad Perihelion Distribution
Abstract
The observation that the orbits of long-period Kuiper Belt objects (KBOs) are anomalously clustered in physical space has recently prompted the Planet Nine hypothesis—the proposed existence of a distant and eccentric planetary member of our solar system. Within the framework of this model, a Neptune-like perturber sculpts the orbital distribution of distant KBOs through a complex interplay of resonant and secular effects, such that in addition to perihelion-circulating objects, the surviving orbits get organized into apsidally aligned and anti-aligned configurations with respect to Planet Nine's orbit. In this work, we investigate the role of Kuiper Belt initial conditions on the evolution of the outer solar system using numerical simulations. Intriguingly, we find that the final perihelion distance distribution depends strongly on the primordial state of the system, and we demonstrate that a bimodal structure corresponding to the existence of both aligned and anti-aligned clusters is only reproduced if the initial perihelion distribution is assumed to extend well beyond ~36 au. The bimodality in the final perihelion distance distribution is due to the existence of permanently stable objects, with the lower perihelion peak corresponding to the anti-aligned orbits and the higher perihelion peak corresponding to the aligned orbits. We identify the mechanisms that enable the persistent stability of these objects and locate the regions of phase space in which they reside. The obtained results contextualize the Planet Nine hypothesis within the broader narrative of solar system formation and offer further insight into the observational search for Planet Nine.
Additional Information
© 2018 The American Astronomical Society. Received 2018 January 17; revised 2018 April 29; accepted 2018 April 30; published 2018 May 25. We thank Elizabeth Bailey, Christopher Spalding, and Juliette Becker for useful conversations, and Fred Adams for a careful review of the draft. We thank the anonymous referee for valuable comments that led to the improvement of the manuscript. T.K. is grateful to the Johnson and Johnson WAVE Fellowship for funding as well as to the Caltech Student-Faculty Program for their support of this work. K.B. acknowledges the generous support of the David and Lucile Packard Foundation.Attached Files
Published - Khain_2018_AJ_155_250.pdf
Accepted Version - 1804.11281.pdf
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Additional details
- Eprint ID
- 86622
- Resolver ID
- CaltechAUTHORS:20180525-102419749
- Johnson and Johnson
- Caltech Summer Undergraduate Research Fellowship (SURF)
- David and Lucile Packard Foundation
- Created
-
2018-05-25Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department, Division of Geological and Planetary Sciences