Origin and Evolution of Long-Period Comets
Abstract
Nesvorny et al. (2017) performed the first end-to-end, 4.5 billion year simulations of the formation and evolution of the cometary reservoirs, focusing primarily on short-period (Jupiter-family and Halley-type) comets. Here we report the results of our simulations of long-period comets (Vokrouhlicky et al. 2019). The calculations begin with 1 million test particles in a massive disk beyond Neptune, with Uranus and Neptune migrating in a "jumping Jupiter" model of the early dynamical instability (Brasser et al. 2009, Nesvorny and Morbidelli 2012, Nesvorny and Vokrouhlicky 2016). The simulations include the effects of the four giant planets, galactic tides, and passing stars. Some 5% of the particles survive for 4.5 Gyr, with 90% of those in the Oort Cloud. The populations of the inner and outer Oort Cloud are roughly equal. Francis (2005) inferred from LINEAR data that there were 11 long-period comets/year with perihelia < 4 AU and absolute magnitude 10.9. Our simulations, which are calibrated to the Jupiter Trojan implantation efficiency from the original planetesimal disk, predicts about 4 such comets/year. If we assume the magnitude-size relationship from Sosa and Fernandez (2011), these are cometary nuclei with diameters > 0.6 km. Beyond perihelion distances of 15 au, the number of comets increases rapidly, and the inner Oort Cloud is the dominant source beyond 20 au. Surveys such as LSST should soon reveal the true structure of the Oort Cloud (Silsbee and Tremaine 2016).
This research was supported by the Czech Science Foundation (DV) and by NASA Emerging Worlds program (DN). References: Brasser R, Morbidelli A, Gomes R, Tsiganis K, Levison HF (2009). A&A 507, 1053; Francis PJ (2005). ApJ 635, 1348; Nesvorny D, Morbidelli A (2012). AJ 144, 117; Nesvorny D, Vokrouhlicky D (2016). ApJ 825, 94; Nesvorny D, Vokrouhlicky D, Dones L, Levison HF, Kaib N, Morbidelli A (2017). ApJ 845, 27; Silsbee K, Tremaine S (2016). AJ 152, 103; Sosa A, Fernandez JA (2011). MNRAS 416, 767; Vokrouhlicky D, Nesvorny D, Dones L (2019). arXiv:1904.00728- Publication:
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AAS/Division of Dynamical Astronomy Meeting
- Pub Date:
- June 2019
- Bibcode:
- 2019DDA....5020104D