Theoretical models of planetary system formation: mass vs. semi-major axis

Alibert, Y.; Carron, F.; Fortier, A.; Pfyffer, Samuel; Benz, W.; Swoboda, D.; Mordasini, C. (2013). Theoretical models of planetary system formation: mass vs. semi-major axis Astronomy & Astrophysics, 558(A109), A109. EDP Sciences 10.1051/0004-6361/201321690

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Context. Planet formation models have been developed during the past years to try to reproduce what has been observed of both the solar system and the extrasolar planets. Some of these models have partially succeeded, but they focus on massive planets and, for the sake of simplicity, exclude planets belonging to planetary systems. However, more and more planets are now found in planetary systems. This tendency, which is a result of radial velocity, transit, and direct imaging surveys, seems to be even more pronounced for low-mass planets. These new observations require improving planet formation models, including new physics, and considering the formation of systems. Aims: In a recent series of papers, we have presented some improvements in the physics of our models, focussing in particular on the internal structure of forming planets, and on the computation of the excitation state of planetesimals and their resulting accretion rate. In this paper, we focus on the concurrent effect of the formation of more than one planet in the same protoplanetary disc and show the effect, in terms of architecture and composition of this multiplicity. Methods: We used an N-body calculation including collision detection to compute the orbital evolution of a planetary system. Moreover, we describe the effect of competition for accretion of gas and solids, as well as the effect of gravitational interactions between planets. Results: We show that the masses and semi-major axes of planets are modified by both the effect of competition and gravitational interactions. We also present the effect of the assumed number of forming planets in the same system (a free parameter of the model), as well as the effect of the inclination and eccentricity damping. We find that the fraction of ejected planets increases from nearly 0 to 8% as we change the number of embryos we seed the system with from 2 to 20 planetary embryos. Moreover, our calculations show that, when considering planets more massive than ~5 M⊕, simulations with 10 or 20 planetary embryos statistically give the same results in terms of mass function and period distribution.

Item Type:

Journal Article (Original Article)


Rectorate and Services > Rektorat


Alibert, Y.;
Carron, F.;
Fortier, A.;
Pfyffer, Samuel0000-0002-0225-4974;
Benz, W.;
Swoboda, D. and
Mordasini, C.


Q Science > QB Astronomy
Q Science > QC Physics




EDP Sciences


[UNSPECIFIED] European Research Council ; [UNSPECIFIED] Swiss National Science Foundation ; [UNSPECIFIED] Alexander von Humboldt Foundation


[UNSPECIFIED] ERC Starting Grant No. 239605 "Planetogenesis"




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Date Deposited:

29 Jan 2019 09:15

Last Modified:

12 Aug 2020 11:30

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Additional Information:

Reproduced with permission from Astronomy & Astrophysics, © ESO

Uncontrolled Keywords:

planets and satellites: formation / planets and satellites: composition / planetary systems




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