FORMATION OF SUPER-EARTH MASS PLANETS AT 125–250 AU FROM A SOLAR-TYPE STAR
- Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
We investigate pathways for the formation of icy super-Earth mass planets orbiting at 125–250 AU around a 1 M{sub ⊙} star. An extensive suite of coagulation calculations demonstrates that swarms of 1 cm–10 m planetesimals can form super-Earth mass planets on timescales of 1–3 Gyr. Collisional damping of 10{sup −2}−10{sup 2} cm particles during oligarchic growth is a highlight of these simulations. In some situations, damping initiates a second runaway growth phase where 1000–3000 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.
- OSTI ID:
- 22862889
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 806; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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