Porto Oscillation Code (POSC)

TL;DR

The Porto Oscillation Code (POSC) is a numerical tool developed since 1995 to compute linear adiabatic oscillations in solar-type star models, applicable from pre-main sequence to sub-giant phases, with various boundary conditions.

Contribution

This paper reviews the key features, numerical methods, and options of the POSC, highlighting its capabilities for stellar oscillation calculations across different evolutionary stages.

Findings

Accurately computes oscillation frequencies and eigenfunctions.

Supports various boundary conditions and numerical techniques.

Applicable to stars with 0.8 to 4 solar masses.

Abstract

The Porto Oscillation Code (POSC) has been developed in 1995 and improved over the years, with the main goal of calculating linear adiabatic oscillations for models of solar-type stars. It has also been used to estimate the frequencies and eigenfunctions of stars from the pre-main sequence up to the sub-giant phase, having a mass between 0.8 and 4 solar masses. The code solves the linearised perturbation equations of adiabatic pulsations for an equilibrium model using a second order numerical integration method. The possibility of using Richardson extrapolation is implemented. Several options for the surface boundary condition can be used. In this work we briefly review the key ingredients of the calculations, namely the equations, the numerical scheme and the output.