The Maximum Mass Solar Nebula and the early formation of planets
journal contributionposted on 25.07.2018, 13:47 by C. J. Nixon, A. R. King, J. E. Pringle
Current planet formation theories provide successful frameworks with which to interpret the array of new observational data in this field. However, each of the two main theories (core accretion, gravitational instability) is unable to explain some key aspects. In many planet formation calculations, it is usual to treat the initial properties of the planet-forming disc (mass, radius, etc.) as free parameters. In this paper, we stress the importance of setting the formation of planet-forming discs within the context of the formation of the central stars. By exploring the early stages of disc formation, we introduce the concept of the Maximum Mass Solar Nebula, as opposed to the oft-used minimum mass solar nebula. It is evident that almost all protoplanetary discs start their evolution in a strongly self-gravitating state. In agreement with almost all previous work in this area, we conclude that on the scales relevant to planet formation these discs are not gravitationally unstable to gas fragmentation, but instead form strong, transient spiral arms. These spiral arms can act as efficient dust traps allowing the accumulation and subsequent fragmentation of the dust (but not the gas). This phase is likely to populate the disc with relatively large planetesimals on short time-scales while the disc is still veiled by a dusty-gas envelope. Crucially, the early formation of large planetesimals overcomes the main barriers remaining within the core accretion model. A prediction of this picture is that essentially all observable protoplanetary discs are already planet hosting.
CJN is supported by the Science and Technology Facilities Council (grant number ST/M005917/1). The Theoretical Astrophysics Group at the University of Leicester is supported by an STFC Consolidated Grant.
CitationMonthly Notices of the Royal Astronomical Society, 2018, 477 (3), pp. 3273-3278 (6)
Author affiliation/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy
VersionVoR (Version of Record)
Published inMonthly Notices of the Royal Astronomical Society
PublisherOxford University Press (OUP), Royal Astronomical Society
Science & TechnologyPhysical SciencesAstronomy & Astrophysicsaccretion, accretion discsgravitationhydrodynamicsplanets and satellites: formationplanets and satellites: generalSELF-GRAVITATING DISCSMULTIPLE STAR PROPERTIESYOUNG STELLAR OBJECTSPLANETESIMAL FORMATIONPROTOPLANETARY DISCSPROTOSTELLAR DISCSMOLECULAR CLOUDSGIANT PLANETSSPIRAL MORPHOLOGYCLUSTER FORMATION