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Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits.
Scott J Kenyon1, Benjamin C Bromley
1Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, Massachusetts 02138, USA. skenyon@cfa.harvard.edu
Nature
|December 4, 2004
Summary
A passing star likely scattered the dwarf planet Sedna into its distant orbit, challenging current models of the Kuiper belt. This event also presents a small chance of capturing extrasolar planets, offering new avenues for research.
Area of Science:
- Astronomy
- Planetary Science
- Astrophysics
Background:
- The Kuiper belt, a region of icy bodies, extends to about 50 astronomical units (AU) from the Sun.
- Most Kuiper belt objects are influenced by Neptune's gravity.
- The dwarf planet Sedna (2003 VB12) has an unusual orbit with a perihelion of 70 AU, beyond Neptune's influence.
Purpose of the Study:
- To explain the origin of Sedna's extreme orbit.
- To investigate the role of external gravitational influences on Kuiper belt objects.
- To explore the possibility of extrasolar object capture.
Main Methods:
- Simulating gravitational interactions between the Solar System and passing stars.
- Analyzing the orbital dynamics of objects like Sedna.
- Calculating probabilities of scattering and capture events.
Main Results:
- A passing star encounter could scatter objects from the Kuiper belt into orbits like Sedna's with approximately 50% probability.
- There is about a 10% chance Sedna was captured from the outer disk of a passing star.
- High-inclination orbits of captured objects could indicate the presence of extrasolar planets.
Conclusions:
- External stellar encounters provide a plausible explanation for Sedna's unique orbit.
- The detection of high-inclination objects could confirm the presence of extrasolar planets within our Solar System.
- Further research into these capture events may reveal more about planetary system formation and evolution.
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