The rate of stellar encounters along a migrating orbit of the Sun
| Autor: | Lucie Jílková, S.F. Portegies Zwart, Anthony G. A. Brown, C. A. Martínez-Barbosa |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Physics
Earth and Planetary Astrophysics (astro-ph.EP) Planetesimal Solar System 010504 meteorology & atmospheric sciences Milky Way Astronomy Velocity dispersion FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Galaxy Space and Planetary Science Planet 0103 physical sciences Orbit (dynamics) Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Heliocentric orbit Astrophysics::Galaxy Astrophysics Astrophysics - Earth and Planetary Astrophysics 0105 earth and related environmental sciences |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY (ISSN 0035-8711), 464(2), 2290-2300 MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY (ISSN 0035-8711) |
| Popis: | The frequency of Galactic stellar encounters the Solar system experienced depends on the local density and velocity dispersion along the orbit of the Sun in the Milky Way galaxy. We aim at determining the effect of the radial migration of the solar orbit on the rate of stellar encounters. As a first step we integrate the orbit of the Sun backwards in time in an analytical potential of the Milky Way. We use the present-day phase-space coordinates of the Sun, according to the measured uncertainties. The resulting orbits are inserted in an N-body simulation of the Galaxy, where the stellar velocity dispersion is calculated at each position along the orbit of the Sun. We compute the rate of Galactic stellar encounters by employing three different solar orbits ---migrating from the inner disk, without any substantial migration, and migrating from the outer disk. We find that the rate for encounters within $4\times10^5$ AU from the Sun is approximately 21, 39 and 63 Myr$^{-1}$, respectively. The stronger encounters establish the outer limit of the so-called parking zone, which is the region in the plane of the orbital eccentricities and semi-major axes where the planetesimals of the Solar system have been perturbed only by interactions with stars belonging to the Sun's birth cluster. We estimate the outer edge of the parking zone at semi-major axes of 250--1300 AU (the outward and inward migrating orbits reaching the smallest and largest values, respectively), which is one order of magnitude smaller than the determination made by Portegies Zwart & J��lkov�� (2015). We further discuss the effect of stellar encounters on the stability of the hypothetical Planet 9. 11 pages, 7 figures. Accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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