Astronomy and Astrophysics – Astrophysics – Earth and Planetary Astrophysics
Scientific paper
2010-09-23
Astronomy and Astrophysics
Astrophysics
Earth and Planetary Astrophysics
Accepted for publication in the Astrophysical Journal. 15 pages, 4 figures, 1 table
Scientific paper
The standard model of planet formation considers an initial phase in which planetesimals form from a dust disk, followed by a phase of mutual planetesimal-planetesimal collisions, leading eventually to the formation of planetary embryos. However, there is a potential transition phase (which we call the "snowball phase"), between the formation of the first planetesimals and the onset of mutual collisions amongst them, which has often been either ignored or underestimated in previous studies. In this snowball phase, isolated planetesimals move on Keplerian orbits and grow solely via the direct accretion of sub-cm sized dust entrained with the gas in the protoplanetary disk. Using a simplified model in which planetesimals are progressively produced from the dust, we consider the expected sizes to which the planetesimals can grow before mutual collisions commence and derive the dependence of this size on a number of critical parameters, including the degree of disk turbulence, the planetesimal size at birth and the rate of planetesimal creation. For systems in which turbulence is weak and the planetesimals are created at a low rate and with relatively small birth size, we show that the snowball growth phase can be very important, allowing planetesimals to grow by a factor of 10^6 in mass before mutual collisions take over. In such cases, the snowball growth phase can be the dominant mode to transfer mass from the dust to planetesimals. Moreover, such growth can take place within the typical lifetime of a protoplanetary gas disk. A noteworthy result is that ... ...(see the paper). For the specific case of close binaries such as Alpha Centauri ... ... (see the paper). From a more general perspective, these preliminary results suggest that an efficient snowball growth phase provides a large amount of "room at the bottom" for theories of planet formation.
Ge Jian
Payne Matthew J.
Thébault Philippe
Xie Ji-Wei
Zhou Ji-Lin
No associations
LandOfFree
From Dust To Planetesimal: The Snowball Phase ? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with From Dust To Planetesimal: The Snowball Phase ?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and From Dust To Planetesimal: The Snowball Phase ? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-339120