Very Large Array Observations of Winds from Massive Stars

TL;DR

This paper presents VLA observations of three massive stars, revealing that their stellar winds deviate from classical models by exhibiting asymmetries, inhomogeneities, and variability, thus challenging standard assumptions.

Contribution

It provides detailed measurements of flux densities, sizes, spectral indices, and mass loss rates for three stars, demonstrating nonclassical wind behaviors.

Findings

Winds show asymmetries and inhomogeneities.

Flux densities and mass loss rates vary over time.

Winds deviate from classical isotropic, homogeneous models.

Abstract

The classical model for free-free emission from ionized stellar winds is based on the assumption of a stationary, isotropic and homogeneous wind. However, since there exist objects whose wind behaviour deviates from the standard model, during the last decade these assumptions have been questioned. In this work, we present results for 3 bright sources: P Cyg, Cyg OB2 No.12 and WR 147. These objects have been reported to possess winds that deviate from the basic assumptions. We have obtained flux densities, sizes, spectral indices and mass loss rates for each of the targets. These parameters allow us to analyze possible asymmetries, inhomogeneities and time variations in the flux densities. These features confirm the nonclassical behaviour of these winds.