Accretion Disks and Eruptive Phenomena

Abstract

In the 1700’s, Immanuel Kant and the Marquis de Laplace proposed that the solar system collapsed from a gaseous medium of roughly uniform density ([79], [105]). A flattened gaseous disk — the protosolar nebula — formed out of this cloud. The Sun contracted out of material at the center of the disk, while the planets condensed in the outer portions. Despite its simplicity, this model suffered from the angular momentum problem inherent to star formation: a cloud of gas and dust with the diameter of the solar system and the mass of the Sun has too much angular momentum to collapse to the Sun’s present size. It took 150 years to solve this problem. C. von Weiszäcker worked out the basic physics of a viscous accretion disk, building on previous realizations that a turbulent viscosity could move material inwards and angular momentum outwards through the protosolar nebula ([178], [179]). With Lüst’s steady-state solution ([119]), Kant’s nebular hypothesis no longer suffered from the angular momentum problem and became the leading model for solar system formation.KeywordsAccretion DiskAccretion RateCentral StarMain Sequence StarTauri StarThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.