Formation of Super-Earth Mass Planets at 125-250 AU from a Solar-type Star

S. J. Kenyon, B. C. Bromley

(Submitted on 22 Jan 2015)

We investigate pathways for the formation of icy super-Earth mass planets orbiting at 125-250 AU around a 1 solar mass star. An extensive suite of coagulation calculations demonstrates that swarms of 1 cm to 10 m planetesimals can form super-Earth mass planets on time scales of 1-3 Gyr. Collisional damping of 0.01-100 cm particles during oligarchic growth is a highlight of these simulations. In some situations, damping initiates a second runaway growth phase where 100-3000 km protoplanets grow to super-Earth sizes.

Our results establish the initial conditions and physical processes required for in situ formation of super-Earth planets at large distances from the host star. For nearby dusty disks in HD 107146, HD 202628, and HD 207129, ongoing super-Earth formation at 80-150 AU could produce gaps and other structures in the debris. In the solar system, forming a putative planet X at a < 300 AU (a > 1000 AU) requires a modest (very massive) protosolar nebula.

Comments:43 pages of text, 24 figures, submitted to ApJ

Subjects:Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)

Cite as:arXiv:1501.05659 [astro-ph.EP] (or arXiv:1501.05659v1 [astro-ph.EP] for this version)

Submission history From: Scott J. Kenyon   [v1] Thu, 22 Jan 2015 21:00:14 GMT (369kb)

http://arxiv.org/abs/1501.05659