Did Jupiter's core form in the innermost parts of the Sun's protoplanetary disc?
Abstract
Jupiter's core is generally assumed to have formed beyond the snow line. Here we consider an alternative scenario that Jupiter's core may have accumulated in the innermost part of the protoplanetary disc. A growing body of research suggests that small particles (`pebbles') continually drift inward through the disc. If a fraction of drifting pebbles is trapped at the inner edge of the disc, several Earth-mass cores can quickly grow. Subsequently, the core may migrate outward beyond the snow line via planet-disc interactions. Of course, to reach the outer Solar system Jupiter's core must traverse the terrestrial planet-forming region. We use N-body simulations including synthetic forces from an underlying gaseous disc to study how the outward migration of Jupiter's core sculpts the terrestrial zone. If the outward migration is fast (τmig ∼ 104 yr), the core simply migrates past resident planetesimals and planetary embryos. However, if its migration is slower (τmig ∼ 105 yr) the core clears out solids in the inner disc by shepherding objects in mean motion resonances. In many cases, the disc interior to 0.5-1 AU is cleared of embryos and most planetesimals. By generating a mass deficit close to the Sun, the outward migration of Jupiter's core may thus explain the absence of terrestrial planets closer than Mercury. Jupiter's migrating core often stimulates the growth of another large (∼Earth-mass) core - that may provide a seed for Saturn's core - trapped in an exterior resonance. The migrating core also may transport a fraction of terrestrial planetesimals, such as the putative parent bodies of iron meteorites, to the asteroid belt.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2016
- DOI:
- 10.1093/mnras/stw431
- arXiv:
- arXiv:1602.06573
- Bibcode:
- 2016MNRAS.458.2962R
- Keywords:
-
- planets and satellites: formation;
- planets and satellites: gaseous planets;
- planets and satellites: terrestrial planets;
- planet-disc interactions;
- protoplanetary discs;
- planetary systems;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 12 pages, 6 figures. Accepted to MNRAS. Blog post about the paper at http://planetplanet.net/2016/02/21/did-the-solar-system-form-inside-0ut/