Long-Lived Planetesimal Discs
نویسندگان
چکیده
We investigate the survival of planetesimal discs over Gyr timescales, using a unified approach that is applicable to all Keplerian discs of solid bodies – dust grains, asteroids, planets, etc. Planetesimal discs can be characterized locally by four parameters: surface density, semimajor axis, planetesimal size and planetesimal radial velocity dispersion. Any planetesimal disc must have survived all dynamical processes, including gravitational instability, dynamical chaos, gravitational scattering, physical collisions, and radiation forces, that would lead to significant evolution over its lifetime. These processes lead to a rich set of constraints that strongly restrict the possible properties of long-lived discs. Within this framework, we also discuss the detection of planetesimal discs using radial velocity measurements, transits, microlensing, and the infrared emission from the planetesimals themselves or from dust generated by planetesimal collisions.
منابع مشابه
Migration of giant planets in planetesimal discs
Planets orbiting a planetesimal circumstellar disc can migrate inward from their initial positions because of dynamical friction between planets and planetesimals. The migration rate depends on the disc mass and on its time evolution. Planets that are embedded in long-lived planetesimal discs, having total mass of 10 − 0.01M⊙, can migrate inward a large distance and can survive only if the inne...
متن کاملLimits on the location of planetesimal formation in self-gravitating protostellar discs
In this Letter we show that if planetesimals form in spiral features in self-gravitating discs, as previously suggested by the idealised simulations of Rice et al, then in realistic protostellar discs, this process will be restricted to the outer regions of the disc (i.e. at radii in excess of several tens of A.U.). This restriction relates to the requirement that dust has to be concentrated in...
متن کاملPlanetesimal formation via fragmentation in self-gravitating protoplanetary discs
An unsolved issue in the standard core accretion model for gaseous planet formation is how kilometre-sized planetesimals form from, initially, micron-sized dust grains. Solid growth beyond metre sizes can be difficult both because the sticking efficiency becomes very small, and because these particles should rapidly migrate into the central star. We consider here how metre sized particles evolv...
متن کاملVortices in self-gravitating gaseous discs
Vortices have recently received much attention in the research of planet formation, as they are believed to play a role in the formation of km-sized planetesimals by collecting dust particles in their centres. However, vortex dynamics is commonly studied in nonself-gravitating discs. The main goal here is to examine the effects of disc self-gravity on vortex dynamics. For this purpose, we emplo...
متن کاملDUst around NEarby Stars. The survey observational results
Context. Debris discs are a consequence of the planet formation process and constitute the fingerprints of planetesimal systems. Their solar system counterparts are the asteroid and Edgeworth-Kuiper belts. Aims. The DUNES survey aims at detecting extra-solar analogues to the Edgeworth-Kuiper belt around solar-type stars, putting in this way the solar system into context. The survey allows us to...
متن کامل