Heating mechanisms of protostellar accretion disks

• Grant number: 16/22092-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2017
• End date: December 31, 2017
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Vera Jatenco Silva Pereira
• Grantee: Natália Fernanda de Souza Andrade
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/10559-5 - Investigation of high energy and plasma astrophysics phenomena: theory, numerical simulations, observations, and instrument development for the Cherenkov Telescope Array (CTA), AP.ESP

Abstract

Accretion disks are observed around young stars, as T Tauri stars. In order to have transport of disk material for the star it is necessary that the disk particles lose some of its rotational energy and "fall" toward the central object. The most promising angular momentum transport mechanism is the magneto-rotational instability (MRI). However, this instability requires that thegas particles are attached to magnetic field lines. For this to occur, a fraction of the particles must be charged. As the temperature of the disk is too low, the particles have low degrees of ionization. Thus, for the MRI to act on the entire disk higher temperatures are required. There are several studies in the literature using the Alfvén waves damping as extra energy source for the disk. In these works the waves suffer the following damping mechanisms: nonlinear, turbulent and dust cyclotron damping. The objective of this project is to analyze which of these damping mechanisms is more efficient for the disk heating as a function of radial distance and high. Although in the literature these damping mechanisms have been used independently, they can act in conjunction. In this way, we will search the way in which this coupling can be obtained in order to maximize the disk heating. Meanwhile, a numerical code is being built to solve the disk equations, including the combination of the three mechanisms mentioned as an additional source of energy. (AU)