Asteroseismology and Rotation in the Main Sequence

Author(s)

Andressa Maria Jendreieck

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD)
• Defense date: 2011-03-21

Examining board members

Eduardo Janot Pacheco; Vera Jatenco Silva Pereira; Simone Daflon dos Santos

• Advisor: Eduardo Janot Pacheco

Abstract

Asteroseismology provides a unique opportunity to probe the inner properties of stars through the study of stellar oscillations. These oscillations depend on the physics of the cavity where they are formed. However, the stellar rotation introduces an axis of symmetry and lifts the degeneracy of the frequencies, thus hindering the identification. The goal of this work was to study the dependence of the oscillation frequency on the stellar rotation velocities for models of intermediate mass along the main sequence. This study was performed through the modeling of stars with a wide range of masses and rotational velocities (2-8 Msun, 20-100km/s) with the codes CESAM/FILOU. The behavior of the rotational \\textit and its asymmetry for the modes g2, g1, p1 and p2 showed a dependence on other physical parameters, as well as rotation. The asymmetry presents interesting variations leading to a diagnostic method of evolution: when multiple modes are observed, the asymmetries lead to a precise determination of the evolution phase of the star. Representative models for the star HD50844 were compared with the observational data. The lack of identification of the modes (l,m) and the large number of frequencies does not allow to obtain accurate results. (AU)

• FAPESP's process: 09/06647-0 - Asteroseismology in the Main Sequence
• Grantee: Andressa Maria Jendreieck
• Support Opportunities: Scholarships in Brazil - Master